Arquivo da tag: Evolução

Talking Neanderthals challenge the origins of speech (Science Daily)

Date:

March 2, 2014

Source: University of New England

Summary: We humans like to think of ourselves as unique for many reasons, not least of which being our ability to communicate with words. But ground-breaking research shows that our ‘misunderstood cousins,’ the Neanderthals, may well have spoken in languages not dissimilar to the ones we use today.

A model of an adult Neanderthal male head and shoulders on display in the Hall of Human Origins in the Smithsonian Museum of Natural History in Washington, D.C. Reconstruction based on the Shanidar 1 fossil (c. 80-60 kya). Credit: By reconstruction: John Gurche; photograph: Tim Evanson [CC-BY-SA-2.0], via Wikimedia Commons

We humans like to think of ourselves as unique for many reasons, not least of which being our ability to communicate with words. But ground-breaking research by an expert from the University of New England shows that our ‘misunderstood cousins,’ the Neanderthals, may well have spoken in languages not dissimilar to the ones we use today.

Pinpointing the origin and evolution of speech and human language is one of the longest running and most hotly debated topics in the scientific world. It has long been believed that other beings, including the Neanderthals with whom our ancestors shared Earth for thousands of years, simply lacked the necessary cognitive capacity and vocal hardware for speech.

Associate Professor Stephen Wroe, a zoologist and palaeontologist from UNE, along with an international team of scientists and the use of 3D x-ray imaging technology, made the revolutionary discovery challenging this notion based on a 60,000 year-old Neanderthal hyoid bone discovered in Israel in 1989.

“To many, the Neanderthal hyoid discovered was surprising because its shape was very different to that of our closest living relatives, the chimpanzee and the bonobo. However, it was virtually indistinguishable from that of our own species. This led to some people arguing that this Neanderthal could speak,” A/Professor Wroe said.

“The obvious counterargument to this assertion was that the fact that hyoids of Neanderthals were the same shape as modern humans doesn’t necessarily mean that they were used in the same way. With the technology of the time, it was hard to verify the argument one way or the other.”

However advances in 3D imaging and computer modelling allowed A/Professor Wroe’s team to revisit the question.

“By analysing the mechanical behaviour of the fossilised bone with micro x-ray imaging, we were able to build models of the hyoid that included the intricate internal structure of the bone. We then compared them to models of modern humans. Our comparisons showed that in terms of mechanical behaviour, the Neanderthal hyoid was basically indistinguishable from our own, strongly suggesting that this key part of the vocal tract was used in the same way.

“From this research, we can conclude that it’s likely that the origins of speech and language are far, far older than once thought.”

Journal Reference:

  1. Ruggero D’Anastasio, Stephen Wroe, Claudio Tuniz, Lucia Mancini, Deneb T. Cesana, Diego Dreossi, Mayoorendra Ravichandiran, Marie Attard, William C. H. Parr, Anne Agur, Luigi Capasso. Micro-Biomechanics of the Kebara 2 Hyoid and Its Implications for Speech in NeanderthalsPLoS ONE, 2013; 8 (12): e82261 DOI: 10.1371/journal.pone.0082261

Theory on origin of animals challenged: Some animals need extremely little oxygen (Science Daily)

Date: February 17, 2014

Source: University of Southern Denmark

Summary: One of science’s strongest dogmas is that complex life on Earth could only evolve when oxygen levels in the atmosphere rose to close to modern levels. But now studies of a small sea sponge fished out of a Danish fjord shows that complex life does not need high levels of oxygen in order to live and grow.

Sea sponge Halichondria panicea was used in the experiment at the University of Southern Denmark. Credit: Daniel Mills/SDU

One of science’s strongest dogmas is that complex life on Earth could only evolve when oxygen levels in the atmosphere rose to close to modern levels. But now studies of a small sea sponge fished out of a Danish fjord shows that complex life does not need high levels of oxygen in order to live and grow.

The origin of complex life is one of science’s greatest mysteries. How could the first small primitive cells evolve into the diversity of advanced life forms that exists on Earth today? The explanation in all textbooks is: Oxygen. Complex life evolved because the atmospheric levels of oxygen began to rise app. 630 — 635 million years ago.

However new studies of a common sea sponge from Kerteminde Fjord in Denmark shows that this explanation needs to be reconsidered. The sponge studies show that animals can live and grow even with very limited oxygen supplies.

In fact animals can live and grow when the atmosphere contains only 0.5 per cent of the oxygen levels in today’s atmosphere.

“Our studies suggest that the origin of animals was not prevented by low oxygen levels,” says Daniel Mills, PhD at the Nordic Center for Earth Evolution at the University of Southern Denmark.

Together with Lewis M. Ward from the California Institute of Technology he is the lead author of a research paper about the work in the journal PNAS.

A little over half a billion years ago, the first forms of complex life — animals — evolved on Earth. Billions of years before that life had only consisted of simple single-celled life forms. The emergence of animals coincided with a significant rise in atmospheric oxygen, and therefore it seemed obvious to link the two events and conclude that the increased oxygen levels had led to the evolution of animals.

“But nobody has ever tested how much oxygen animals need — at least not to my knowledge. Therefore we decided to find out,” says Daniel Mills.

The living animals that most closely resemble the first animals on Earth are sea sponges. The species Halichondria panicea lives only a few meters from the University of Southern Denmark’s Marine Biological Research Centre in Kerteminde, and it was here that Daniel Mills fished out individuals for his research.

“When we placed the sponges in our lab, they continued to breathe and grow even when the oxygen levels reached 0.5 per cent of present day atmospheric levels,” says Daniel Mills.

This is lower than the oxygen levels we thought were necessary for animal life.

The big question now is: If low oxygen levels did not prevent animals from evolving — then what did? Why did life consist of only primitive single-celled bacteria and amoebae for billions of years before everything suddenly exploded and complex life arose?

“There must have been other ecological and evolutionary mechanisms at play. Maybe life remained microbial for so long because it took a while to develop the biological machinery required to construct an animal. Perhaps the ancient Earth lacked animals because complex, many-celled bodies are simply hard to evolve,” says Daniel Mills.

His colleagues from the Nordic Center for Earth Evolution have previously shown that oxygen levels have actually risen dramatically at least one time before complex life evolved. Although plenty of oxygen thus became available it did not lead to the development of complex life.

Journal Reference:

  1. Daniel B. Mills, Lewis M. Ward, CarriAyne Jones, Brittany Sweeten, Michael Forth, Alexander H. Treusch and Donald E. Canfield. The oxygen requirements of the earliest animalsPNAS, February 17, 2014

Humanity’s forgotten return to Africa revealed in DNA (New Scientist)

20:00 03 February 2014 by Catherine Brahic

Call it humanity’s unexpected U-turn. One of the biggest events in the history of our species is the exodus out of Africa some 65,000 years ago, the start ofHomo sapiens‘ long march across the world. Now a study of southern African genes shows that, unexpectedly, another migration took western Eurasian DNA back to the very southern tip of the continent 3000 years ago.

According to conventional thinking, the Khoisan tribes of southern Africa, have lived in near-isolation from the rest of humanity for thousands of years. In fact, the study shows that some of their DNA matches most closely people from modern-day southern Europe, including Spain and Italy.

Because Eurasian people also carry traces of Neanderthal DNA, the finding also shows – for the first time – that genetic material from our extinct cousin may be widespread in African populations.

The Khoisan tribes of southern Africa are hunter-gatherers and pastoralists who speak unique click languages. Their extraordinarily diverse gene pool split from everyone else’s before the African exodus.

Ancient lineages

“These are very special, isolated populations, carrying what are probably the most ancient lineages in human populations today,” says David Reich of Harvard University. “For a lot of our genetic studies we had treated them as groups that had split from all other present-day humans before they had split from each other.”

So he and his colleagues were not expecting to find signs of western Eurasian genes in 32 individuals belonging to a variety of Khoisan tribes. “I think we were shocked,” says Reich.

The unexpected snippets of DNA most resembled sequences from southern Europeans, including Sardinians, Italians and people from the Basque region (see “Back to Africa – but from where?“). Dating methods suggested they made their way into the Khoisan DNA sometime between 900 and 1800 years ago – well before known European contact with southern Africa (see map).

Archaeological and linguistic studies of the region can make sense of the discovery. They suggest that a subset of the Khoisan, known as the Khoe-Kwadi speakers, arrived in southern Africa from east Africa around 2200 years ago. Khoe-Kwadi speakers were – and remain – pastoralists who make their living from herding cows and sheep. The suggestion is that they introduced herding to a region that was otherwise dominated by hunter-gatherers.

Khoe-Kwadi tribes

Reich and his team found that the proportion of Eurasian DNA was highest in Khoe-Kwadi tribes, who have up to 14 per cent of western Eurasian ancestry. What is more, when they looked at the east African tribes from which the Khoe-Kwadi descended, they found a much stronger proportion of Eurasian DNA – up to 50 per cent.

That result confirms a 2012 study by Luca Pagani of the Wellcome Trust Sanger Institute in Hinxton, UK, which found non-African genes in people living in Ethiopia. Both the 2012 study and this week’s new results show that the Eurasian genes made their way into east African genomes around 3000 years ago. About a millennium later, the ancestors of the Khoe-Kwadi headed south, carrying a weaker signal of the Eurasian DNA into southern Africa.

The cultural implications are complex and potentially uncomfortably close to European colonial themes. “I actually am not sure there’s any population that doesn’t have west Eurasian [DNA],” says Reich.

“These populations were always thought to be pristine hunter-gatherers who had not interacted with anyone for millennia,” says Reich’s collaborator, linguist Brigitte Pakendorf of the University of Lyon in France. “Well, no. Just like the rest of the world, Africa had population movements too. There was simply no writing, no Romans or Greeks to document it.”

Twist in tale

There’s one more twist to the tale. In 2010 a research team – including Reich – published the first draft genome of a Neanderthal. Comparisons with living humans revealed traces of Neanderthal DNA in all humans with one notable exception: sub-Saharan peoples like the Yoruba and Khoisan.

That made sense. After early humans migrated out of Africa around 60,000 years ago, they bumped into Neanderthals somewhere in what is now the Middle East. Some got rather cosy with each other. As their descendants spread across the world to Europe, Asia and eventually the Americas, they spread bits of Neanderthal DNA along with their own genes. But because those descendants did not move back into Africa until historical times, most of this continent remained a Neanderthal DNA-free zone.

Or so it seemed at the time. Now it appears that the Back to Africa migration 3000 years ago carried a weak Neanderthal genetic signal deep into the homeland. Indeed one of Reich’s analyses, published last month, found Neanderthal traces in Yoruba DNA (Nature, DOI: 10.1038/nature12886).

In other words, not only is western Eurasian DNA ancestry a global phenomenon, so is having a bit of Neanderthal living on inside you.

Journal reference: PNAS, DOI: 10.1073/pnas.1313787111

Back to Africa – but from where?

Reich and his colleagues found that DNA sequences in the Khoisan people most closely resemble some found in people who today live in southern Europe. That, however, does not mean the migration back to Africa started in Italy or Spain. More likely, the migration began in what is now the Middle East.

We know that southern Europeans can trace their ancestry to the Middle East. However, in the thousands of years since they – and the ancestors of the Khoisan – left the region, it has experienced several waves of immigration. These waves have had a significant effect on the genes of people living in the Middle East today, and and means southern Europeans are much closer to the original inhabitants of the Levant than modern-day Middle Easterners.

Neanderthals Leave Their Mark on Us (New York Times)

JAN. 29, 2014

A reconstruction of a Neanderthal skeleton, right, with a modern human skeleton in the background. Frank Franklin II/Associated Press

By Carl Zimmer

Ever since the discovery in 2010 that Neanderthals interbred with the ancestors of living humans, scientists have been trying to determine how their DNA affects people today. Now two new studies have traced the history of Neanderthal DNA, and have pinpointed a number of genes that may have medical importance today.

Among the findings, the studies have found clues to the evolution of skin and fertility, as well as susceptibility to diseases like diabetes. More broadly, they show how the legacy of Neanderthals has endured 30,000 years after their extinction.

“It’s something that everyone wanted to know,” said Laurent Excoffier, a geneticist at the University of Bern in Switzerland who was not involved in the research.

Neanderthals, who became extinct about 30,000 years ago, were among the closest relatives of modern humans. They shared a common ancestor with us that lived about 600,000 years ago.

In the 1990s, researchers began finding fragments of Neanderthal DNA in fossils. By 2010 they had reconstructed most of the Neanderthal genome. When they compared it with the genomes of five living humans, they found similarities to small portions of the DNA in the Europeans and Asians.

The researchers concluded that Neanderthals and modern humans must have interbred. Modern humans evolved in Africa and then expanded out into Asia and Europe, where Neanderthals lived. In a 2012 study, the researchers estimated that this interbreeding took place between 37,000 and 85,000 years ago.

Sir Paul A. Mellars, an archaeologist at the University of Cambridge and the University of Edinburgh, who was not involved in the research, said the archaeological evidence suggested the opportunity for modern humans to mate with Neanderthals would have been common once they expanded out of Africa. “They’d be bumping into Neanderthals at every street corner,” he joked.

The first draft of the Neanderthal genome was too rough to allow scientists to draw further conclusions. But recently, researchers sequenced a far more accurate genome from a Neanderthal toe bone.

Scientists at Harvard Medical School and the Max Planck Institute for Evolutionary Anthropology in Germany compared this high-quality Neanderthal genome to the genomes of 1,004 living people. They were able to identify specific segments of Neanderthal DNA from each person’s genome.

“It’s a personal map of Neanderthal ancestry,” said David Reich of Harvard Medical School, who led the research team. He and his colleagues published their results in the journal Nature.

Living humans do not have a lot of Neanderthal DNA, Dr. Reich and his colleagues found, but some Neanderthal genes have become very common. That’s because, with natural selection, useful genes survive as species evolve. “What this proves is that these genes were helpful for non-Africans in adapting to the environment,” Dr. Reich said.

In a separate study published in Science, Benjamin Vernot and Joshua M. Akey of the University of Washington came to a similar conclusion, using a different method.

Mr. Vernot and Dr. Akey looked for unusual mutations in the genomes of 379 Europeans and 286 Asians. The segments of DNA that contained these mutations turned out to be from Neanderthals.

Both studies suggest that Neanderthal genes involved in skin and hair were favored by natural selection in humans. Today, they are very common in living non-Africans.

The fact that two independent studies pinpointed these genes lends support to their importance, said Sriram Sankararaman of Harvard Medical School, a co-author on the Nature paper. “The two methods seem to be converging on the same results.”

It is possible, Dr. Akey speculated, that the genes developed to help Neanderthal skin adapt to the cold climate of Europe and Asia.

But Dr. Akey pointed out that skin performs other important jobs, like shielding us from pathogens. “We don’t understand enough about the biology of those particular genes yet,” he said. “It makes it hard to pinpoint a reason why they’re beneficial.”

Both teams of scientists also found long stretches of the living human genomes where Neanderthal DNA was glaringly absent. This pattern could be produced if modern humans with certain Neanderthal genes could not have as many children on average as people without them. For example, living humans have very few genes from Neanderthals involved in making sperm. That suggests that male human-Neanderthal hybrids might have had lower fertility or were even sterile.

Overall, said Dr. Reich, “most of the Neanderthal genetic material was more bad than good.”

Some of the Neanderthal genes that have endured until today may be influencing people’s health. Dr. Reich and his colleagues identified nine Neanderthal genes in living humans that are known to raise or reduce the risk of various diseases, including diabetes and lupus.

To better understand the legacy of Neanderthals, Dr. Reich and his colleagues are collaborating with the UK Biobank, which collects genetic information from hundreds of thousands of volunteers. The scientists will search for Neanderthal genetic markers, and investigate whether Neanderthal genes cause any noticeable differences in anything from weight to blood pressure to scores on memory tests.

“This experiment of nature has been done,” said Dr. Reich, “and we can study it.”

Correction: January 29, 2014
An earlier version of this article misstated the living groups in which Neanderthal genes involved in skin and hair are very common. They are very common in non-Africans, not non-Asians.

Genomes of Modern Dogs and Wolves Provide New Insights On Domestication (Science Daily)

Jan. 16, 2014 — Dogs and wolves evolved from a common ancestor between 9,000 and 34,000 years ago, before humans transitioned to agricultural societies, according to an analysis of modern dog and wolf genomes from areas of the world thought to be centers of dog domestication.

This chart depicts wolf and dog lineages as they diverge over time. (Credit: Freedma, et al / PLoS Genetics)

The study, published in PLoS Geneticson January 16, 2014, also shows that dogs are more closely related to each other than wolves, regardless of geographic origin. This suggests that part of the genetic overlap observed between some modern dogs and wolves is the result of interbreeding after dog domestication, not a direct line of descent from one group of wolves.

This reflects a more complicated history than the popular story that early farmers adopted a few docile, friendly wolves that later became our beloved, modern-day companions. Instead, the earliest dogs may have first lived among hunter-gatherer societies and adapted to agricultural life later.

“Dog domestication is more complex than we originally thought,” said John Novembre, associate professor in the Department of Human Genetics at the University of Chicago and a senior author on the study. “In this analysis we didn’t see clear evidence in favor of a multi-regional model, or a single origin from one of the living wolves that we sampled. It makes the field of dog domestication very intriguing going forward.”

The team generated the highest quality genome sequences to date from three gray wolves: one each from China, Croatia and Israel, representing three regions where dogs are believed to have originated. They also produced genomes for two dog breeds: a basenji, a breed which originates in central Africa, and a dingo from Australia, both areas that have been historically isolated from modern wolf populations. In addition to the wolves and dogs, they sequenced the genome of a golden jackal to serve as an “outgroup” representing earlier divergence.

Their analysis of the basenji and dingo genomes, plus a previously published boxer genome from Europe, showed that the dog breeds were most closely related to each other. Likewise, the three wolves from each geographic area were more closely related to each other than any of the dogs.

Novembre said this tells a different story than he and his colleagues anticipated. Instead of all three dogs being closely related to one of the wolf lineages, or each dog being related to its closest geographic counterpart (i.e. the basenji and Israeli wolf, or the dingo and Chinese wolf), they seem to have descended from an older, wolf-like ancestor common to both species.

“One possibility is there may have been other wolf lineages that these dogs diverged from that then went extinct,” he said. “So now when you ask which wolves are dogs most closely related to, it’s none of these three because these are wolves that diverged in the recent past. It’s something more ancient that isn’t well represented by today’s wolves.”

Accounting for gene flow between dogs and wolves after domestication was a crucial step in the analyses. According to Adam Freedman, a postdoctoral fellow at the University of California, Los Angeles (UCLA) and the lead author on the study, gene flow across canid species appears more pervasive than previously thought.

“If you don’t explicitly consider such exchanges, these admixture events get confounded with shared ancestry,” he said. “We also found evidence for genetic exchange between wolves and jackals. The picture emerging from our analyses is that these exchanges may play an important role in shaping the diversification of canid species.”

Domestication apparently occurred with significant bottlenecks in the historical population sizes of both early dogs and wolves. Freedman and his colleagues were able to infer historical sizes of dog and wolf populations by analyzing genome-wide patterns of variation, and show that dogs suffered a 16-fold reduction in population size as they diverged from wolves. Wolves also experienced a sharp drop in population size soon after their divergence from dogs, implying that diversity among both animals’ common ancestors was larger than represented by modern wolves.

The researchers also found differences across dog breeds and wolves in the number of amylase (AMY2B) genes that help digest starch. Recent studies have suggested that this gene was critical to domestication, allowing early dogs living near humans to adapt to an agricultural diet. But the research team surveyed genetic data from 12 additional dog breeds and saw that while most dog breeds had high numbers of amylase genes, those not associated with agrarian societies, like the Siberian husky and dingo, did not. They also saw evidence of this gene family in wolves, meaning that it didn’t develop exclusively in dogs after the two species diverged, and may have expanded more recently after domestication.

Novembre said that overall, the study paints a complex picture of early domestication.

“We’re trying to get every thread of evidence we can to reconstruct the past,” he said. “We use genetics to reconstruct the history of population sizes, relationships among populations and the gene flow that occurred. So now we have a much more detailed picture than existed before, and it’s a somewhat surprising picture.”

Journal Reference:

  1. Adam H. Freedman, Ilan Gronau, Rena M. Schweizer, Diego Ortega-Del Vecchyo, Eunjung Han, Pedro M. Silva, Marco Galaverni, Zhenxin Fan, Peter Marx, Belen Lorente-Galdos, Holly Beale, Oscar Ramirez, Farhad Hormozdiari, Can Alkan, Carles Vilà, Kevin Squire, Eli Geffen, Josip Kusak, Adam R. Boyko, Heidi G. Parker, Clarence Lee, Vasisht Tadigotla, Adam Siepel, Carlos D. Bustamante, Timothy T. Harkins, Stanley F. Nelson, Elaine A. Ostrander, Tomas Marques-Bonet, Robert K. Wayne, John Novembre. Genome Sequencing Highlights the Dynamic Early History of DogsPLoS Genetics, 2014; 10 (1): e1004016 DOI:10.1371/journal.pgen.1004016

Modern Caterpillars Feed at Higher Temperatures in Response to Climate Change (Science Daily)

Dec. 19, 2013 — Caterpillars of two species of butterflies in Colorado and California have evolved to feed rapidly at higher temperatures and at a broader range of temperatures over the past 40 years, suggesting that they are evolving quickly to cope with a hotter, more variable climate.

A Colias (sulphur) butterfly. (Credit: By Greg Hume (Own work) [CC-BY-SA-3.0], via Wikimedia Commons)

The work, led by Joel Kingsolver at UNC-Chapel Hill, represents a rare instance of how recent climate change affects physiological traits, such as how the body regulates feeding behavior.

“To our knowledge, this is the first instance where we show changes in physiological traits in response to recent climate change,” says Kingsolver, Kenan Distinguished Professor of Biology in UNC’s College of Arts and Sciences, whose work appears today in the journal Functional Ecology.

Caterpillars can eat and grow only when it’s not too cold and not too hot, explains Kingsolver. But when temperatures are ideal, caterpillars eat with reckless abandon and can gain up to 20 percent of their body weight in an hour. That growth determines their ability to survive, how quickly they become adult butterflies and their ultimate reproductive success.

Jessica Higgins, a graduate student in Kingsolver’s lab who spearheaded the study, worked with fellow graduate student Heidi MacLean, Lauren Buckley, currently at the University of Washington, and Kingsolver to compare modern caterpillars to their ancestors from 40 years ago.

Their results show that the two related species of Colias (sulphur) butterflies have adapted in two ways: they not only broadened the range of their ideal feeding temperatures but also shifted their optimal feeding temperature to a higher one.

In their work, the researchers measured changes in climate at the two study sites and then examined changes in how fast caterpillar ate using current and historical data from the 1970s, collected by Kingsolver’s graduate adviser Ward Watt.

Although they found little change in the average air temperature at both study sites, they noticed that the frequency of hot temperatures — that is, temperatures that exceeded 82 degrees Fahrenheit -increased two-fold in Colorado and four-fold in California over the past 40 years.

In response to these temperature fluctuations, modern caterpillars in Colorado ate faster at higher temperatures than their 1970s counterparts. In California, the modern caterpillars ate faster at both high and low temperatures than did their ancestors, but their optimal feeding temperatures did not change.

“These two species of caterpillars adapted to the increased frequency of higher temperatures over 40 years in two different ways, but both are better suited than their ancestors to thrive in a hotter, more variable climate,” says Higgins. “Our climate is changing. The thermal physiology of these species is changing, too.”

Rapid Evolution of Novel Forms: Environmental Change Triggers Inborn Capacity for Adaptation (Science Daily)

Dec. 12, 2013 — In the classical view of evolution, species experience spontaneous genetic mutations that produce various novel traits — some helpful, some detrimental. Nature then selects for those most beneficial, passing them along to subsequent generations. 

Surface form and cave form of Astyanax mexicanus differ in many morphological traits, the most prominent being the loss of pigmentation and the loss of eyes in the cave forms. (Credit: Courtesy of Nicolas Rohner)

It’s an elegant model. It’s also an extremely time-consuming process likely to fail organisms needing to cope with sudden, potentially life-threatening changes in their environments. Surely some other mechanism could enable more rapid adaptive response. In this week’s edition of the journal Science, a team of researchers from Harvard Medical School and Whitehead Institute report that, at least in the case of one variety of cavefish, that other agent of change is the heat shock protein known as HSP90.

“It’s a very cool story in terms of the speed of evolution,” says Nicolas Rohner, lead author of the Science paper and a postdoctoral researcher in the lab of Harvard Medical School Genetics Professor Clifford Tabin.

Rohner notes that at some point many thousands of years ago, a population of Astyanax mexicanus (a fish indigenous to northeastern Mexico) was swept from its hospitable river home into the unfriendly confines of underwater caves. Facing a dramatically different environment, the fish were forced to adapt. Living in near total darkness, the fish did away with their pigmentation, developed heightened sensory systems to detect changes in water pressure and the presence of prey and, perhaps most strikingly, they lost their eyes. Although seemingly counterintuitive, the loss of eyes is thought to be an “adaptive” or beneficial trait, as the maintenance of a complex but now useless organ would come at a high metabolic cost. Thus, the fish could reallocate their finite physiological resources to biological functions more helpful in the cave setting.

Eye loss in these fish is considered to be a demonstration of an evolutionary concept known as “standing genetic variation,” which argues that pools of genetic mutations — some potentially helpful — exist in a given population but are normally kept silent. The manifestations of these mutations, that is, their impact on observable phenotypes, don’t emerge until the population encounters stressful conditions. But what exactly keeps those mutations at bay?

Enter Whitehead Member Susan Lindquist, whose research has shown that HSP90 silences such genetic variation in a variety of organisms, from fruit flies, to yeast, to plants. Lindquist’s work found that the normally robust cellular reservoir of HSP90 becomes depleted during periods of physiological stress. The loss of HSP90 activity allowed phenotypic changes to emerge quite rapidly. Although some emergent traits found in her lab were not adaptive, some clearly were.

“The delicate balance of protein folding — especially that controlled by HSP90 — holds the key,” says Lindquist, who is also a professor of biology at MIT and an investigator of the Howard Hughes Medical Institute. “Moderate changes in the environment create stresses on protein folding, causing minor changes in the genome to have much larger effects. Because HSP90 governs the folding of the key regulators of growth and development it produces a fulcrum point for evolutionary change.”

Having seen Tabin’s work on the genetics of eye loss in cavefish, she proposed a research collaboration to determine whether HSP90 had been an evolutionary role-player in this vertebrate. The Tabin and Lindquist labs devised a complex set of experiments with cavefish and surface fish of the same species. Surface fish raised in the presence of a drug that blocks HSP90 activity (thereby mimicking a stressful environment) displayed significant variation in eye size — clearly implicating HSP90’s effects on this trait. Conversely, cavefish raised in the same conditions showed no increase in variation in the size of their eye orbits (although the cave fish have no eyes, their skulls retain the orbital cavity where their eyes once were). Intriguingly, however, these fish emerged with small orbits, showing that the genetics governing eye size remains responsive to HSP90.

Although impressive, these findings were chemically induced, leaving open the question of whether such HSP90-related effects would have been seen in nature. To answer this, researchers examined a host of conditions — ranging from pH to oxygen content to temperature — found in the surface and cave waters that are home to these fish. They discovered a considerable difference in conductivity, as measured by salinity, between cave and surface. Because low conductivity, a condition found in the caves, can trigger a heat shock response, they raised surface fish in water whose conductivity equaled that of native caves.

The results were essentially the same: fish raised in conditions of low conductivity showed significant variation in eye size. The scientists had shown that an environmental stressor could have the same effects as the chemical inhibition of HSP90.

“This is the first time that we can see in a natural setting where the stress came from and observe the variation that results,” says Tabin.

Adds Rohner: “This is the first study showing that this HSP90-mediated mechanism can be applied to vertebrates for real morphological adaptive traits.”

For Dan Jarosz, a former postdoctoral researcher in Lindquist’s lab, the study is an important validation of Lindquist’s work on evolution. Jarosz, now Assistant Professor of Chemical and Systems Biology and of Developmental Biology at Stanford University, had been involved in much of Lindquist’s work on HSP90 as a driver of evolution in yeast. He believes this latest work should help quiet those who are skeptical of the impact of this mechanism throughout the plant and animal kingdoms.

“We now have enough evidence to say that large, rapid environmental change can reveal new variation and change the outcomes of real evolution in nature,” he says.

This work is supported by the National Institutes of Health and the Damon Runyon Cancer Research Foundation.

Journal Reference:

  1. N. Rohner, D. F. Jarosz, J. E. Kowalko, M. Yoshizawa, W. R. Jeffery, R. L. Borowsky, S. Lindquist, C. J. Tabin. Cryptic Variation in Morphological Evolution: HSP90 as a Capacitor for Loss of Eyes in CavefishScience, 2013; 342 (6164): 1372 DOI: 10.1126/science.1240276

Domestication of Dogs May Have Elaborated On a Pre-Existing Capacity of Wolves to Learn from Humans (Science Daily)

Dec. 3, 2013 — Wolves can learn from observing humans and pack members where food is hidden and recognize when humans only pretend to hide food, reports a study for the first time in the open-access journal Frontiers in Psychology. These findings imply that when our ancestors started to domesticate dogs, they could have built on a pre-existing ability of wolves to learn from others, not necessarily pack members.

The researchers conclude that the ability to learn from other species, including humans, is not unique to dogs but was already present in their wolf ancestors. Prehistoric humans and the ancestors of dogs could build on this ability to better coordinate their actions. (Credit: Wolf Science Center)

A paper published recently in the journalScience suggested that humans domesticated dogs about 18 thousand years ago, possibly from a European population of grey wolves that is now extinct. But it remains unknown how much the ability of dogs to communicate with people derives from pre-existing social skills of their wolf ancestors, rather than from novel traits that arose during domestication.

In a recent study, Friederike Range and Zsófia Virányi from the Messerli Research Institute at the University of Veterinary Medicine Vienna investigated if wolves and dogs can observe a familiar “demonstrator” — a human or a specially trained dog — to learn where to look for food within a meadow. The subjects were 11 North American grey wolves and 14 mutts, all between 5 and 7 months old, born in captivity, bottle-fed, and hand-raised in packs at the Wolf Science Center of Game Park Ernstbrunn, Austria.

The wolves and dogs were two to four times more likely to find the snack after watching a human or dog demonstrator hide it, and this implies that they had learnt from the demonstration instead of only relying on their sense of smell. Moreover, they rarely looked for the food when the human demonstrator had only pretended to hide it, and this proves that they had watched very carefully.

The wolves were less likely to follow dog demonstrators to hidden food. This does not necessarily mean that they were not paying attention to dog demonstrators: on the contrary, the wolves may have been perceptive enough to notice that the demonstrator dogs did not find the food reward particularly tasty themselves, and so simply did not bother to look for it.

The researchers conclude that the ability to learn from other species, including humans, is not unique to dogs but was already present in their wolf ancestors. Prehistoric humans and the ancestors of dogs could build on this ability to better coordinate their actions.

Journal Reference:

  1. Friederike Range and Zsófia Virányi. Social learning from humans or conspecifics: differences and similarities between wolves and dogsFrontiers In Science, 2013 DOI:10.3389/fpsyg.2013.00868

Homem evolui mais devagar que macaco, diz estudo (Folha de S.Paulo)

24 de outubro de 2013

Reportagem da Folha de SP mostra que pesquisa descobriu que diferenças entre espécies está em genes ativos

A comparação da atividade genética de humanos com a de chimpanzés sugere que o Homo sapiens está evoluindo de forma mais lenta que os macacos. A descoberta foi feita por cientistas que investigam por que o homem e seu primo mais próximo são tão diferentes, apesar de terem 98% do DNA idêntico.

O segredo das diferenças físicas e comportamentais está em quais genes são de fato ativos em cada espécie. Analisando células embrionárias, a brasileira Carolina Marchetto, do Instituto Salk, de San Diego (EUA), descobriu mecanismos que freiam a taxa de transformação genética da espécie humana.

A descoberta favorece a hipótese de que o advento da cultura desacelerou a evolução biológica: uma vez que humanos se adaptam a distintos ambientes usando o conhecimento, nossa espécie não depende mais tanto de variação genética para evoluir e sobreviver a mudanças.

Já os macacos, mamíferos de cognição mais limitada, precisam que seu DNA evolua de forma rápida para sobreviver a mudanças: eles não têm como compensar a falta de características inatas necessárias usando apenas conhecimento e tecnologia.

Mas o DNA humano também não carece de evoluir? “Não sabemos o que estamos pagando por isso em termos de adaptação, mas por enquanto funciona de forma eficiente”, diz Marchetto.

O trabalho da cientista, descrito hoje na revista “Nature”, ajuda a explicar o mistério da maior diversidade do DNA símio. Um leigo pode achar que todos os chimpanzés são iguais, mas uma só colônia selvagem desses macacos na África tem mais variabilidade genética do que toda a humanidade.

O PULO DO GENE

Segundo o estudo de Marcheto, a maior variabilidade genética dos macacos tem a ver com os chamados transpósons, genes que saltam de um lugar para outro dos cromossomos. Nesse processo, os transpósons reorganizam o genoma, ativando alguns genes e desativando outros.

Esses “genes saltadores” são bastante ativos em chimpanzés e bonobos (macacos igualmente próximos da linhagem humana). Em humanos, o transpóson é suprimido por dois outros genes que são ativados em abundância e inibem o “pulo” genético.

Chimpanzés, de certa forma, precisam de transpósons. Com ferramentas rudimentares e sem linguagem para transmitir conhecimento, eles têm de oferecer maior variabilidade genética à seleção natural para que ela os torne mais bem adaptados, caso o ambiente se altere.

A pesquisa de Marchetto só foi possível porque seu o laboratório no Salk, liderado pelo biólogo Fred Gage, domina a técnica de reverter células ao estágio embrionário.

O material usado na pesquisa foi extraído da pele de macacos e pessoas, pois há uma série de limitações para o uso de embriões em experimentos científicos.

Revertido ao estágio de “células pluripotentes induzidas”, o tecido cutâneo se comporta como embrião, e é possível investigar a biologia molecular dos estágios iniciais do desenvolvimento, quando o surgimento de diversidade genética tem consequências futuras.

“Uma das coisas especiais do nosso estudo é que a reprogramação de células de chimpanzés e bonobos nos dá um modelo para começar a estudar questões evolutivas que antes não tínhamos como abordar”, diz Marchetto.

RUMO AO CÉREBRO

As diferenças de ativação de genes entre humanos e chimpanzés, explica, não se restringem a células embrionárias. A ideia de Marcheto e de seus colegas agora é transformar essas células em neurônios, por exemplo, para entender como a biologia molecular de ambos se altera durante a formação do cérebro.

(Rafael Garcia/ Folha de São Paulo)

http://www1.folha.uol.com.br/ciencia/2013/10/1361208-homem-evolui-mais-devagar-que-macaco-diz-estudo.shtml

Language and Tool-Making Skills Evolved at the Same Time (Science Daily)

Sep. 3, 2013 — Research by the University of Liverpool has found that the same brain activity is used for language production and making complex tools, supporting the theory that they evolved at the same time.

Three hand axes produced by participants in the experiment. Front, back and side views are shown. (Credit: Image courtesy of University of Liverpool)

Researchers from the University tested the brain activity of 10 expert stone tool makers (flint knappers) as they undertook a stone tool-making task and a standard language test.

Brain blood flow activity measured

They measured the brain blood flow activity of the participants as they performed both tasks using functional Transcranial Doppler Ultrasound (fTCD), commonly used in clinical settings to test patients’ language functions after brain damage or before surgery.

The researchers found that brain patterns for both tasks correlated, suggesting that they both use the same area of the brain. Language and stone tool-making are considered to be unique features of humankind that evolved over millions of years.

Darwin was the first to suggest that tool-use and language may have co-evolved, because they both depend on complex planning and the coordination of actions but until now there has been little evidence to support this.

Dr Georg Meyer, from the University Department of Experimental Psychology, said: “This is the first study of the brain to compare complex stone tool-making directly with language.

Tool use and language co-evolved

“Our study found correlated blood-flow patterns in the first 10 seconds of undertaking both tasks. This suggests that both tasks depend on common brain areas and is consistent with theories that tool-use and language co-evolved and share common processing networks in the brain.”

Dr Natalie Uomini from the University’s Department of Archaeology, Classics & Egyptology, said: “Nobody has been able to measure brain activity in real time while making a stone tool. This is a first for both archaeology and psychology.”

The research was supported by the Leverhulme Trust, the Economic and Social Research Council and the British Academy. It is published in PLOS ONE.

Journal Reference:

  1. Natalie Thaïs Uomini, Georg Friedrich Meyer. Shared Brain Lateralization Patterns in Language and Acheulean Stone Tool Production: A Functional Transcranial Doppler Ultrasound StudyPLoS ONE, 2013; 8 (8): e72693 DOI: 10.1371/journal.pone.0072693

Why Animals Compare the Present With the Past (Science Daily)

May 30, 2013 — Humans, like other animals, compare things. We care not only how well off we are, but whether we are better or worse off than others around us, or than we were last year. New research by scientists at the University of Bristol shows that such comparisons can give individuals an evolutionary advantage.

The ‘contrast effect’ has been reported in a number of living things, including bees. (Credit: © Daniel Prudek / Fotolia)

According to standard theory, the best response to current circumstances should be unaffected by what has happened in the past. But the Bristol study, published in the journalScience, shows that in a changing, unpredictable world it is important to be sensitive to past conditions.

The research team, led by Professor John McNamara in Bristol’s School of Mathematics, built a mathematical model to understand how animals should behave when they are uncertain about the pattern of environmental change. They found that when animals are used to rich conditions but then conditions suddenly worsen, they should work less hard than animals exposed to poor conditions all along.

The predictions from the model closely match findings from classic laboratory experiments in the 1940s, in which rats were trained to run along a passage to gain food rewards. The rats ran more slowly for small amounts of food if they were used to getting large amounts of food, compared to control rats that were always rewarded with the smaller amount.

This so-called ‘contrast effect’ has also been reported in bees, starlings and a variety of mammals including newborn children, but until now it lacked a convincing explanation.

Dr Tim Fawcett, a research fellow in Bristol’s School of Biological Sciences and a co-author on the study, said: “The effects in our model are driven by uncertainty. In changing environments, conditions experienced in the past can be a valuable indicator of how things will be in the future.”

This, in turn, affects how animals should respond to their current situation. “An animal that is used to rich conditions thinks that the world is generally a good place,” Dr Fawcett explained. “So when conditions suddenly turn bad, it interprets this as a temporary ‘blip’ and hunkers down, expecting that rich conditions will return soon. In contrast, an animal used to poor conditions expects those conditions to persist, and so cannot afford to rest.”

The model also predicts the reverse effect, in which animals work harder for food when conditions suddenly improve, compared to animals experiencing rich conditions all along. This too has been found in laboratory experiments on a range of animals.

The Bristol study highlights unpredictable environmental fluctuations as an important evolutionary force. “Rapid changes favour individuals that are responsive and able to adjust their behaviour in the light of past experience,” said Dr Fawcett. “The natural world is a dynamic and unpredictable place, but evolutionary models often neglect this. Our work suggests that models of more complex environments are important for understanding behaviour.”

Journal Reference:

  1. J. M. McNamara, T. W. Fawcett, A. I. Houston. An Adaptive Response to Uncertainty Generates Positive and Negative Contrast EffectsScience, 2013; 340 (6136): 1084 DOI: 10.1126/science.1230599

A mulher que encolheu o cérebro humano (O Globo)

Suzana Herculano é a primeira brasileira a falar na prestigiada conferência TED

Ela debaterá o cérebro de 86 bilhões de neurônios (e não 100 bilhões, como se acreditava) e como o homem se diferenciou dos primatas 

Publicado:24/05/13 – 7h00; Atualizado:24/05/13 – 11h41

Suzana Herculano-Houzel, professora do Instituto de Ciências Biomédicas da UFRJFoto: Guito Moreto

Suzana Herculano-Houzel, professora do Instituto de Ciências Biomédicas da UFRJ Guito Moreto

Neurocientista da UFRJ, Suzana Herculano-Houzel é a primeira brasileira a participar da TED (Tecnologia, Entretenimento e Design, em português) — prestigiada série de conferências que reúne grandes nomes das mais diversas áreas do conhecimento para debater novas ideias. Suzana falará no dia 12 de junho, sob o tema “Ouça a natureza”, e destacará suas descobertas únicas sobre o cérebro humano.

Sobre o que vai falar na TED?

Vou falar sobre o cérebro humano e mostrar como ele não é um cérebro especial, uma exceção à regra. Nossas pesquisas nos revelaram que se trata apenas de um cérebro de primata grande. O notável é que passamos a ter um cérebro enorme, do tamanho que nenhum outro primata tem, nem os maiores, porque inventamos o cozimento dos alimentos e, com isso, passamos a ter um número enorme de neurônios.

O cozimento foi fundamental para nos tornarmos humanos?

Sim, burlamos a limitação energética imposta pela dieta crua. E a implicação bacana e irônica é que, com isso, conseguimos liberar tempo no cérebro para nos dedicarmos a outras coisas (que não buscar alimentos), como criar a agricultura, as civilizações, a geladeira e a eletricidade. Até o ponto em que conseguir comida cozida e calorias em excesso ficou tão fácil que, agora, temos o problema inverso: estamos comendo demais. Por isso, voltamos à saladinha.

Se alimentarmos orangotangos e gorilas com comida cozida eles serão tão inteligentes quanto nós?

Sim, porque não seriam limitados pelo número reduzido de calorias que conseguem com a comida crua. Claro que nós fizemos uma inovação cultural ao inventar a cozinha. Tem uma diferença entre dar comida cozida para o animal e ele ter o desenvolvimento cultural do cozimento. Mas, ainda assim, se em todas as refeições eles tiverem acesso à comida cozida, daqui a 200 mil ou 300 mil anos eles terão o cérebro maior. Com a alimentação que têm hoje, não é possível terem um cérebro maior dado o corpo grande que têm. É uma coisa ou outra.

Somos especiais?

A gente não é especial coisa alguma. Somos apenas um primata que burlou as regras energéticas e conseguiu botar mais neurônios no cérebro de um jeito que nenhum outro animal conseguiu. Por isso estudamos os outros animais e não o contrário.

Persistem ainda mitos sobre o cérebro? Como o dos 100 bilhões de neurônios, que seus estudos demonstraram que são, na verdade, 86 bilhões?

Sim, eles continuam existindo, mesmo na neurociência. O nosso trabalho já é muito citado como referência. As coisas estão mudando. E o mais legal é que é por conta da ciência tupiniquim, o que eu acho maravilhoso. Mas vemos que é um processo, que ainda tem muita gente que insiste no número antigo.

O novo manual de diagnóstico de doenças mentais dos EUA (que serve de referência para todo o mundo, inclusive para a OMS) foi lançado na semana passada em meio à controvérsia. Especialistas acham que são tantos transtornos que praticamente não resta mais nenhum espaço para a normalidade. Qual a sua opinião?

Acho que essa discussão é muito necessária, justamente para reconhecermos o que são as variações ao redor do normal e quais são os extremos problemáticos e doentios de fato. Então, a discussão é importante, ótima a qualquer momento. Mas acho também que há muita informação errada e sensacionalista circulando, sobretudo sobre o déficit de atenção. As estatísticas variam muito de país para país, às vezes porque varia o número de médicos que reconhece a criança como portadora do distúrbio. E acho que ainda há um problema enorme, um medo enorme do estereótipo da doença mental. Até hoje ainda existe uma resistência louca em ir a um psiquiatra. E acho que, pelo contrário, ganhamos muito reconhecendo que existem transtornos e que eles podem ser tratados.

Ainda há muito estigma?

O maior problema hoje em dia é que é feio ter um distúrbio no cérebro. Perceba que nem estou falando em transtorno mental. Precisar de remédio para o cérebro é terrível. E temos tanto a ganhar reconhecendo os problemas, fazendo os diagnósticos. O cérebro é tão complexo, tem tanta coisa para dar errado, que o espantoso é que não dê problema em todo mundo sempre. Então, acho normal que boa parte da população tenha algum problema, não me espanta nem um pouco. E, uma vez que se reconhece o problema, que se faz o diagnóstico, há a opção de poder tratar. Se dispomos de um tratamento, por que não usar?

O presidente dos EUA, Barack Obama, recentemente anunciou uma inédita iniciativa de reunir pesquisadores dos mais diversos centros para estudar exclusivamente o cérebro. O que podemos esperar de tamanho esforço científico?

Não só o cérebro, mas o cérebro em atividade. Obama quer ir além do que já tinham feito — estudar a função de diferentes áreas — e entender como se conectam, como falam umas com as outras, ter ideia desse funcionamento integrado, dessa interação. Essa é uma das grandes lacunas do conhecimento: entender como as várias partes do cérebro funcionam ao mesmo tempo. Não sabemos como o cérebro funciona como um todo; é uma das fronteiras finais do conhecimento.

Não sabemos como o cérebro funciona?

Como um todo, não. Sabemos o que as partes fazem, mas não sabemos como se dá a conversa entre elas. Não sabemos a origem da consciência, da sensação do “eu estou aqui agora”. Que áreas são fundamentais para isso? É esse tipo de conhecimento que se está buscando, do cérebro funcionando ao vivo e em cores, em tempo real.

O objetivo não é estudar doenças, então?

Não, o grande objetivo é estudar consciência, memória; entender como o cérebro reúne emoção e lógica, coisas que são fruto da ação coordenada de várias partes. Claro que desse conhecimento todo podem surgir implicações para o Alzheimer e outras doenças. Mas, na verdade, falar em doenças é uma roupagem usada pela divulgação do programa para o público assimilar melhor. Existe esse preconceito de que a ciência só vale quando resolve uma doença.

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Oldest Evidence of Split Between Old World Monkeys and Apes: Primate Fossils Are 25 Million Years Old (Science Daily)

May 15, 2013 — Two fossil discoveries from the East African Rift reveal new information about the evolution of primates, according to a study published online in Nature this week led by Ohio University scientists. 

Artist’s reconstruction of Rukwapithecus (front, center) and Nsungwepithecus (right). (Credit: Mauricio Anton)

The team’s findings document the oldest fossils of two major groups of primates: the group that today includes apes and humans (hominoids), and the group that includes Old World monkeys such as baboons and macaques (cercopithecoids).

Geological analyses of the study site indicate that the finds are 25 million years old, significantly older than fossils previously documented for either of the two groups.

Both primates are new to science, and were collected from a single fossil site in the Rukwa Rift Basin of Tanzania.Rukwapithecus fleaglei is an early hominoid represented by a mandible preserving several teeth. Nsungwepithecus gunnelli is an early cercopithecoid represented by a tooth and jaw fragment.

The primates lived during the Oligocene epoch, which lasted from 34 to 23 million years ago. For the first time, the study documents that the two lineages were already evolving separately during this geological period.

“The late Oligocene is among the least sampled intervals in primate evolutionary history, and the Rukwa field area provides a first glimpse of the animals that were alive at that time from Africa south of the equator,” said Nancy Stevens, an associate professor of paleontology in Ohio University’s Heritage College of Osteopathic Medicine who leads the paleontological team.

Documenting the early evolutionary history of these groups has been elusive, as there are few fossil-bearing deposits of the appropriate age, Stevens explained. Using an approach that dated multiple minerals contained within the rocks, team geologists could determine a precise age for the specimens.

“The rift setting provides an advantage in that it preserves datable materials together with these important primate fossils,” said lead geologist Eric Roberts of James Cook University in Australia.

Prior to these finds, the oldest fossil representatives of the hominoid and cercopithecoid lineages were recorded from the early Miocene, at sites dating millions of years younger.

The new discoveries are particularly important for helping to reconcile a long-standing disagreement between divergence time estimates derived from analyses of DNA sequences from living primates and those suggested by the primate fossil record, Stevens said. Studies of clock-like mutations in primate DNA have indicated that the split between apes and Old

World monkeys occurred between 30 million and 25 million years ago.

“Fossils from the Rukwa Rift Basin in southwestern Tanzania provide the first real test of the hypothesis that these groups diverged so early, by revealing a novel glimpse into this late Oligocene terrestrial ecosystem,” Stevens said.

The new fossils are the first primate discoveries from this precise location within the Rukwa deposits, and two of only a handful of known primate species from the entire late Oligocene, globally.

The scientists scanned the specimens in the Ohio University’s MicroCT scanner, allowing them to create detailed 3-dimensional reconstructions of the ancient specimens that were used for comparisons with other fossils.

“This is another great example that underscores how modern imaging and computational approaches allow us to address more refined questions about vertebrate evolutionary history,” said Patrick O’Connor, co-author and professor of anatomy in Ohio University’s Heritage College of Osteopathic Medicine.

In addition to the new primates, Rukwa field sites have produced several other fossil vertebrate and invertebrate species new to science. The late Oligocene interval is interesting because it provides a final snapshot of the unique species inhabiting Africa prior to large-scale faunal exchange with Eurasia that occurred later in the Cenozoic Era, Stevens said.

A key aspect of the Rukwa Rift Basin project is the interdisciplinary nature of the research team, with paleontologists and geologists working together to reconstruct vertebrate evolutionary history in the context of the developing East African Rift System.

“Since its inception this project has employed a multifaceted approach for addressing a series of large-scale biological and geological questions centered on the East African Rift System in Tanzania,” O’Connor said.

The team’s research, funded by the U.S. National Science Foundation, the Leakey Foundation and the National Geographic Society, underscores the integration of paleontological and geological approaches that are essential for addressing complex issues in vertebrate evolutionary history, the scientists noted.

Co-authors on the study are Patrick O’Connor, Cornelia Krause and Eric Gorscak of Ohio University, Erik Seiffert of SUNY Stony Brook University, Eric Roberts of James Cook University in Australia, Mark Schmitz of Boise State University, Sifa Ngasala of Michigan State University, Tobin Hieronymus of Northeast Ohio Medical University and Joseph Temu of the Tanzania Antiquities Unit.

Journal Reference:

  1. Nancy J. Stevens, Erik R. Seiffert, Patrick M. O’Connor, Eric M. Roberts, Mark D. Schmitz, Cornelia Krause, Eric Gorscak, Sifa Ngasala, Tobin L. Hieronymus, Joseph Temu.Palaeontological evidence for an Oligocene divergence between Old World monkeys and apes.Nature, 2013; DOI: 10.1038/nature12161

Convívio entre homens e cães criou semelhanças genéticas (O Globo)

Amigos há 32 mil anos, a milenar relação entre as duas espécies tem estudo apresentado por zoólogos chineses 

ROBERTA JANSEN

Publicado:17/05/13 – 6h00; Atualizado:17/05/13 – 6h00

<br />Amizade milenar . Um homem e seu cachorro: novo estudo revela que relação já dura 32 mil anos e funciona tão bem porque evoluiu de forma compartilhada<br />Foto: John Hart / APAmizade milenar . Um homem e seu cachorro: novo estudo revela que relação já dura 32 mil anos e funciona tão bem porque evoluiu de forma compartilhada John Hart / AP

RIO- Cachorros podem, de fato, ser os melhores amigos do homem porque compartilham uma história evolutiva em comum muito mais longa do que se imaginava. Estudo publicado esta semana na “Nature Communications” revelou que os cães teriam sido domesticados há 32 mil anos — quase o dobro do que se acreditava. Esta duradoura e intensa relação teria, inclusive, um impacto na genética dos animais e dos homens, que foi ficando parecida em alguns aspectos. Na verdade, conclui o estudo, os cães se auto-domesticaram para serem mais aceitos pelos humanos que, por sua vez, também se adaptaram aos animais.

Um grupo de pesquisadores do Instituto de Zoologia da China, coordenados por Ya-Ping Zhang, obteve o genoma completo de quatro lobos cinzentos de diferentes pontos da Ásia e da Europa, três cachorros nativos do sudoeste da China, e três representantes de raças atuais. Geneticistas confirmaram que os cães nativos da China representam o primeiro estágio da domesticação canina — o genoma deles traz informação sobre a transição de lobos para os cachorros ancestrais, tornando-os uma espécie de “elo perdido” da domesticação.

Os lobos se auto-domesticaram

A equipe descobriu também que os lobos apresentam a maior diversidade genética, enquanto que os cachorros modernos ficam com a menor. Analisando a quantidade de mutações, os especialistas conseguiram estabelecer que a separação entre lobos e cães nativos chineses ocorreu na Ásia, há 32 mil anos.

Diferentemente do que se imaginava, dizem os cientistas, os homens não adotaram filhotes de lobos. Teria sido bem o oposto disso.

O processo provavelmente começou com os lobos que rondavam em torno de populações humanas de caçadores-coletores em busca de restos de alimento e carcaças, num processo que os pesquisadores chamam de auto-domesticação.

— A hipótese mais interessante levantada por essa pesquisa é a auto-domesticação — afirmou Zhang em entrevista. — De acordo com essa hipótese, os primeiros lobos teriam sido atraídos para viver e caçar com os humanos. E com sucessivas mudanças adaptativas, esses animais se tornaram progressivamente mais propensos a viver com os homens.

Nesta situação, os lobos mais agressivos teriam se saído muito mal, porque a tendência seria que fossem mortos pelos homens. Os animais mais mansos, no entanto, teriam se adaptado melhor e se multiplicado. Ou seja, os lobos se auto-domesticaram.

A pesquisa conseguiu estabelecer que a domesticação impôs uma determinante força seletiva nos genes envolvidos na digestão e no metabolismo — provavelmente por conta da mudança de uma dieta estritamente carnívora para uma onívora.

Os genes que governam processos neurológicos complexos também sofreram tal pressão, sobretudo devido à necessidade de redução da agressão e do aumento de complexos processos de interação com os seres humanos.

Curiosamente, o grupo descobriu que a contraparte humana de diversos desses genes, particularmente aqueles envolvidos nos processos neurológicos, também sofreram uma forte pressão seletiva ao longo do tempo, refletindo os fatores ambientais similares vivenciados por homens e cachorros ao longo de milhares de anos de uma relação tão próxima.

Mais dóceis e mansos

Alguns dos genes estão associados a doenças similares no homem e no cão. Outros são ativos na região do córtex pré-frontal, onde os mamíferos tomam decisões sobre o comportamento. Alguns genes estão envolvidos no maior número de conexões entre os neurônios. Um gene em particular, o SLC6A4, é responsável pela codificação da proteína que transporta o neurotransmissor serotonina.

— Outros estudos já haviam revelado que o gene é relacionado ao comportamento agressivo e ao transtorno obsessivo-compulsivo não apenas em homens mas também em cachorros — afirmou Zhang.

Mudança semelhante foi também constatada nos homens — indicando que nós também tivemos que nos tornar menos agressivos para tolerar os outros e viver bem em grupos.

Para o cientista, o estudo da base genética de diversas doenças em cães pode ajudar na compreensão de doenças similares em humanos.

Leia mais sobre esse assunto em http://oglobo.globo.com/ciencia/convivio-entre-homens-caes-criou-semelhancas-geneticas-8415160#ixzz2TluyW7T9 © 1996 – 2013. Todos direitos reservados a Infoglobo Comunicação e Participações S.A. Este material não pode ser publicado, transmitido por broadcast, reescrito ou redistribuído sem autorização.

Computer Scientists Suggest New Spin On Origins of Evolvability: Competition to Survive Not Necessary? (Science Daily)

Apr. 26, 2013 — Scientists have long observed that species seem to have become increasingly capable of evolving in response to changes in the environment. But computer science researchers now say that the popular explanation of competition to survive in nature may not actually be necessary for evolvability to increase.

The average evolvability of organisms in each niche at the end of a simulation is shown. The lighter the color, the more evolvable individuals are within that niche. The overall result is that, as in the first model, evolvability increases with increasing distance from the starting niche in the center. (Credit: Joel Lehman, Kenneth O. Stanley. Evolvability Is Inevitable: Increasing Evolvability without the Pressure to Adapt. PLoS ONE, 2013; 8 (4): e62186 DOI: 10.1371/journal.pone.0062186)

In a paper published this week inPLOS ONE, the researchers report that evolvability can increase over generations regardless of whether species are competing for food, habitat or other factors.

Using a simulated model they designed to mimic how organisms evolve, the researchers saw increasing evolvability even without competitive pressure.

“The explanation is that evolvable organisms separate themselves naturally from less evolvable organisms over time simply by becoming increasingly diverse,” said Kenneth O. Stanley, an associate professor at the College of Engineering and Computer Science at the University of Central Florida. He co-wrote the paper about the study along with lead author Joel Lehman, a post-doctoral researcher at the University of Texas at Austin.

The finding could have implications for the origins of evolvability in many species.

“When new species appear in the future, they are most likely descendants of those that were evolvable in the past,” Lehman said. “The result is that evolvable species accumulate over time even without selective pressure.”

During the simulations, the team’s simulated organisms became more evolvable without any pressure from other organisms out-competing them. The simulations were based on a conceptual algorithm.

“The algorithms used for the simulations are abstractly based on how organisms are evolved, but not on any particular real-life organism,” explained Lehman.

The team’s hypothesis is unique and is in contrast to most popular theories for why evolvability increases.

“An important implication of this result is that traditional selective and adaptive explanations for phenomena such as increasing evolvability deserve more scrutiny and may turn out unnecessary in some cases,” Stanley said.

Stanley is an associate professor at UCF. He has a bachelor’s of science in engineering from the University of Pennsylvania and a doctorate in computer science from the University of Texas at Austin. He serves on the editorial boards of several journals. He has over 70 publications in competitive venues and has secured grants worth more than $1 million. His works in artificial intelligence and evolutionary computation have been cited more than 4,000 times.

Journal Reference:

  1. Joel Lehman, Kenneth O. Stanley. Evolvability Is Inevitable: Increasing Evolvability without the Pressure to AdaptPLoS ONE, 2013; 8 (4): e62186 DOI:10.1371/journal.pone.0062186

Playing for All Kinds of Possibilities (N.Y.Times)

Buckets of Blickets: Children and Logic: A game developed by researchers at the University of California, Berkeley hopes to show how imaginative play in children may influence development of abstract thought.

By DAVID DOBBS

Published: April 22, 2013

When it comes to play, humans don’t play around.

Alison Gopnik and the Gopnik Lab/University of California, Berkeley. Esther and Benny, both 4, play Blickets with Sophie Bridgers in a lab at the University of California, Berkeley. Children, lacking prior biases, excel in the game, based on associations, but adults flunk it.

Other species play, but none play for as much of their lives as humans do, or as imaginatively, or with as much protection from the family circle. Human children are unique in using play to explore hypothetical situations rather than to rehearse actual challenges they’ll face later. Kittens may pretend to be cats fighting, but they will not pretend to be children; children, by contrast, will readily pretend to be cats or kittens — and then to be Hannah Montana, followed by Spider-Man saving the day.

And in doing so, they develop some of humanity’s most consequential faculties. They learn the art, pleasure and power of hypothesis — of imagining new possibilities. And serious students of play believe that this helps make the species great.

The idea that play contributes to human success goes back at least a century. But in the last 25 years or so, researchers like Elizabeth S. SpelkeBrian Sutton-SmithJaak Panksepp and Alison Gopnik have developed this notion more richly and tied it more closely to both neuroscience and human evolution. They see play as essential not just to individual development, but to humanity’s unusual ability to inhabit, exploit and change the environment.

Dr. Gopnik, author of “The Scientist in the Crib” and “The Philosophical Baby,” and a professor of psychology at the University of California, Berkeley, has been studying the ways that children learn to assess their environment through play. Lately she has focused on the distinction between “exploring” new environments and “exploiting” them. When we’re quite young, we are more willing to explore, she finds; adults are more inclined to exploit.

To exploit, one leans heavily on lessons (and often unconscious rules) learned earlier — so-called prior biases. These biases are useful to adults because they save time and reduce error: By going to the restaurant you know is good, instead of the new place across town, you increase the chance that you’ll enjoy the evening.

Most adults are slow to set such biases aside; young children fling them away like bad fruit.

Dr. Gopnik shows this brilliantly with a game she invented with the psychologist David Sobel (her student, now a professor at Brown). In the game, which has the fetching name Blickets, players try to figure out what it is that makes an otherwise undistinguished clay figure a blicket. In some scenarios you can win even if you’re applying a prior bias. In others you can’t.

Last summer I joined Dr. Gopnik behind a wall of one-way glass to watch her lab manager, Sophie Bridgers, play the game with an extremely alert 4-year-old, Esther.

Seated at a child-size table, Esther leaned forward on her elbows to watch as Ms. Bridgers brought out a small bin of clay shapes and told her that some of them were blickets but most were not.

“You cannot tell which ones are blickets by looking at them. But the ones that are blickets have blicketness inside. And luckily,” Ms. Bridgers went on, holding up a box with a red plastic top, “I have my machine. Blicketness makes my machine turn on and play music.”

It’s a ruse, of course. The box responds not to the clay shapes but to a switch under the table controlled by Ms. Bridgers.

Now came the challenge. The game can be played by either of two rules, called “and” and “or.” The “or” version is easier: When a blicket is placed atop the machine, it will light the machine up whether placed there by itself or with other pieces. It is either a blicket or it isn’t; it doesn’t depend on the presence of any other object.

In the “and” trial, however, a blicket reveals its blicketness only if both it and another blicket are placed on the machine; and it will light up the box even if it and the other blicket are accompanied by a non-blicket. It can be harder than it sounds, and this is the game that Esther played.

First, Ms. Bridgers put each of three clay shapes on the box individually — rectangle, then triangle, then a bridge. None activated the machine. Then she put them on the box in three successive combinations.

1. Rectangle and triangle: No response.

2. Rectangle and bridge: Machine lighted up and played a tune!

3. Triangle and bridge: No response.

Ms. Bridgers then picked up each piece in turn and asked Esther whether it was a blicket. I had been indulging my adult (and journalistic) prior bias for recorded observation by filling several pages with notes and diagrams, and I started flipping frantically through my notebook.

I was still looking when Esther, having given maybe three seconds’ thought to the matter, correctly identified all three. The rectangle? “A blicket,” she said. Triangle? A shake of the head: No. Bridge? “A blicket.” A 4-year-old had instantly discerned a rule that I recognized only after Dr. Gopnik explained it to me.

Esther, along with most other 4- and 5-year-olds tested, bested not just me but most of 88 California undergraduates who took the “and” test. We educated grown-ups failed because our prior biases dictated that we play the game by the more common and efficient “or” rule.

“Or” rules apply far more often in actual life, when a thing’s essence seldom depends on another object’s presence. An arrow’s utility may depend on a bow, but its identity as an arrow does not. Since the “or” rule is more likely correct and simpler to use, I grabbed it and clung.

Esther, however, quickly ditched the “or” rule and hit upon the far less likely “and” rule. Such low-probability hypotheses often fail. But children, like adventurous scientists in a lab, will try these wild ideas anyway, because even if they fail, they often produce interesting results.

Esther and her twin brother, Benny (who played another version of the game), generated low-probability hypotheses as fast as I could breathe. “Maybe if you turn it over and put it on the other end!” “Let’s put all three on!” They were hypothesis machines. Their mother, Wendy Wolfson (who is a science writer), told me they’re like this all the time. “It’s like living with a pair of especially inquisitive otters.”

Alas, Dr. Gopnik said, this trait peaks around 4 or 5. After that, we gradually take less interest in seeing what happens and more in getting it right.

Yet this playlike spirit of speculation and exploration does stay with us, both as individuals and as a species. Studies suggest that free, self-directed play in safe environments enhances resilience, creativity, flexibility, social understanding, emotional and cognitive control, and resistance to stress, depression and anxiety. And we continue to explore as adults, even if not so freely. That’s how we got to the Internet, the moon, and Dr. Gopnik’s lab.

Finally, in the long game of evolution, Dr. Gopnik and some of her fellow scientists hypothesize that humans’ extended period of imaginative play, along with the traits it develops, has helped select for the big brain and rich neural networks that characterize Homo sapiens. This may strike you either as a low-probability or a high-probability hypothesis. But it certainly seems worth playing with.

A ontogênese e o aprender (O Estado de São Paulo)

[A despeiro das boas intenções do autor, esse artigo é um retrocesso. Se acumulam evidências e contribuições da antropologia – ver Clifford Geertz, Tim Ingold, Bruno Latour, pra citar apenas alguns – em sentido oposto: desenvolvimento biológico e cultural estão relacionados diretamente; na genética, todo o campo da epigenética se desenvolve também na direção oposta. O discurso do artigo se funda mais em argumentos burocráticos, de organização do conhecimento e da atividade estatal de educação, do que numa discussão verdadeiramente ontológica. RT] 

JC e-mail 4703, de 11 de Abril de 2013.

Artigo de Fernando Reinach publicado no jornal O Estado de São Paulo

O uso da palavra aprender não acompanhou o progresso científico. O resultado é que ainda usamos a mesma palavra para descrever dois fenômenos distintos. Considere a seguinte frase: “Meu filho aprendeu a andar com 1 ano e aprendeu a escrever com 6”. Esses dois processos, descritos como “aprender”, são fenômenos muito diferentes. Não reconhecer essa diferença atrapalha nossa concepção de educação.

Todas as pessoas, de qualquer origem, nascidas em qualquer sociedade nos últimos milhares de séculos, começaram a andar na infância. Por outro lado, somente uma pequena fração das pessoas sabe escrever – e essa capacidade apareceu entre os humanos faz alguns milhares de anos. A razão é simples e conhecida dos biólogos há muito tempo. Andar faz parte de nossa ontogênese; escrever faz parte de nossa herança cultural.

Ontogênese é o nome dado ao processo de formação de um ser vivo. Descreve a transformação de uma semente em árvore ou o surgimento de uma pessoa a partir de um óvulo fecundado. Inicialmente, o conceito de ontogênese era usado para descrever as mudanças de forma durante o desenvolvimento de um ser vivo. Descrevia a formação da espinha vertebral, do coração, o aparecimento dos dedos, o crescimento do cabelo, e todas as mudanças que ocorrem antes do nascimento. Mas o processo de ontogênese continua após o nascimento. O corpo cresce, atingimos a maturidade sexual, paramos de crescer e finalmente começamos a envelhecer. São as etapas inevitáveis de nossa ontogênese.

A ontogênese se caracteriza por uma sequência de eventos que ocorrem de maneira precisa e semelhante em todos os seres vivos de uma espécie. Ela é determinada por nossos genes e modulada pelo meio ambiente. Todas as crianças crescem, mas, se bem alimentadas, crescem mais rápido.

Não é usual utilizarmos a palavra aprender para descrever processos que fazem parte da ontogênese. É por isso que afirmar que “minha filha aprendeu a menstruar aos 13 anos” soa estranho. Ao longo de todo o século XX houve uma melhor compreensão dos processos que fazem parte de nossa ontogênese e se descobriu que um número crescente de etapas pelas quais passamos durante a vida é parte de nossa ontogênese.

É o caso do andar e do falar, cujos aparecimentos estão codificados em nossos genes da mesma maneira que a capacidade de crescer pelos pubianos. É muito difícil, e é necessário um ambiente muito hostil, para evitar que uma criança desenvolva o andar e a capacidade de falar. No caso da fala, sabemos que a língua que a pessoa vai utilizar depende unicamente do ambiente ao qual ela está exposta, mas o surgimento, nos primeiros anos, da capacidade de falar alguma língua faz parte de nossa ontogênese.

Aos poucos, os cientistas descobriram que um número crescente de características que desenvolvemos em alguma fase de nossa vida faz parte de nossa ontogenia. Hoje sabemos que nascemos com a capacidade de fazer adições e subtrações de pequenos números (até três ou quatro). Sabemos que parte de nossa capacidade de julgamento moral, de convivência social, de comunicação por meio de expressões faciais e inúmeras outras características comportamentais também fazem parte de nosso processo ontogenético.

Nossa ontogênese surgiu à medida que nossa espécie e a de nossos ancestrais foi moldada pelo processo de seleção natural. Cada etapa e cada característica de nossa ontogênese foram incorporadas ao longo de milhões de anos e agora fazem parte das características de nossa espécie. O surgimento de um dedo durante nossa vida no útero e de nossa capacidade de somar números pequenos ao nascer é o resultado de um único e longo processo de seleção natural. É por isso que essas capacidades surgem aparentemente de forma espontânea durante as diferentes fases de nossa vida. Como são programadas para ocorrer, seu aparecimento é difícil de ser evitado e, caso seu aparecimento seja inibidos violentamente, as consequências podem ser nefastas para o indivíduo.

A distinção entre esses dois fenômenos seria mais fácil se a palavra aprender fosse restrita à aquisição de novas características e habilidades que não fazem parte de nosso processo ontogenético. Fazer operações matemáticas com números grandes, escrever, andar de bicicleta, calcular a órbita de um satélite e programar um computador são capacidades que podemos adquirir porque nosso corpo e cérebro têm a flexibilidade para incorporar novos comportamentos e conhecimentos, mas não foram moldadas pela seleção natural nem incorporadas à nossa ontogênese.

Essas habilidades foram descobertas muito recentemente pelo homem e derivam da evolução cultural. Esses aprendizados podem ser incluídos no repertório de cada um de nós de maneira opcional, num processo que chamamos de educação. E, como todos sabemos, sua incorporação depende de um grande esforço e dedicação de quem ensina e de quem aprende, leva um longo tempo e consome muita energia dos indivíduos e da sociedade.

Reconhecer as mudanças que fazem parte de nossa ontogênese e separar e cultivar de maneira distinta as mudanças ontogenéticas das induzidas pelo processo educacional podem gerar seres humanos mais felizes. Mas para isso não podemos confundir os dois fenômenos que hoje chamamos de “aprender”.

Fernando Reinach é biólogo.

Environmental Change Triggers Rapid Evolution (Science Daily)

Apr. 8, 2013 — Environmental change can drive hard-wired evolutionary changes in animal species in a matter of generations. A University of Leeds-led study, published in the journal Ecology Letters, overturns the common assumption that evolution only occurs gradually over hundreds or thousands of years.

Female soil mite. (Credit: Umeå universitet.)

Instead, researchers found significant genetically transmitted changes in laboratory populations of soil mites in just 15 generations, leading to a doubling of the age at which the mites reached adulthood and large changes in population size. The results have important implications in areas such as disease and pest control, conservation and fisheries management because they demonstrate that evolution can be a game-changer even in the short-term.

Professor Tim Benton, of the University of Leeds’ Faculty of Biological Sciences, said: “This demonstrates that short-term ecological change and evolution are completely intertwined and cannot reasonably be considered separate. We found that populations evolve rapidly in response to environmental change and population management. This can have major consequences such as reducing harvesting yields or saving a population heading for extinction.”

Although previous research has implied a link between short-term changes in animal species’ physical characteristics and evolution, the Leeds-led study is the first to prove a causal relationship between rapid genetic evolution and animal population dynamics in a controlled experimental setting.

The researchers worked with soil mites that were collected from the wild and then raised in 18 glass tubes. Forty percent of adult mites were removed every week from six of the glass tubes. A similar proportion of juveniles were removed each week in a further six tubes, while no “harvesting” was conducted in the remaining third of the tubes.

Lead author Dr Tom Cameron, a postdoctoral Fellow in the Faculty of Biological Sciences at Leeds at the time of the research and now based in Umeå University, Sweden, said: “We saw significant evolutionary changes relatively quickly. The age of maturity of the mites in the tubes doubled over about 15 generations, because they were competing in a different way than they would in the wild. Removing the adults caused them to remain as juveniles even longer because the genetics were responding to the high chance that they were going to die as soon as they matured. When they did eventually mature, they were so enormous they could lay all of their eggs very quickly.”

The initial change in the mites’ environment — from the wild into the laboratory — had a disastrous effect on the population, putting the mites on an extinction trajectory. However, in every population, including those subjected to the removal of adults or juveniles, the trajectory switched after only five generations of evolution and the population sizes began to increase.

The researchers found that the laboratory environment was selecting for those mites that grew more slowly. Under the competitive conditions in the tubes, the slow growing mites were more fertile when they matured, meaning they could have more babies.

Dr Cameron said: “The genetic evolution that resulted in an investment in egg production at the expense of individual growth rates led to population growth, rescuing the populations from extinction. This is evolutionary rescue in action and suggests that rapid evolution can help populations respond to rapid environmental change.”

Short-term ecological responses to the environment — for instance, a reduction in the size of adults because of a lack of food — and hard-wired evolutionary changes were separated by placing mites from different treatments into a similar environment for several generations and seeing whether differences persisted.

Professor Benton said: “The traditional idea would be that if you put animals in a new environment they stay basically the same but the way they grow changes because of variables like the amount of food. However, our study proves that the evolutionary effect — the change in the underlying biology in response to the environment — can happen at the same time as the ecological response. Ecology and evolution are intertwined,” he said.

Unpicking evolutionary change from ecological responses is particularly important in areas such as the management of fisheries, where human decisions can result in major changes to an entire population’s environment and life histories. The size at which cod in the North Sea mature is about half that of 50 years ago and this change has been linked to a collapse in the cod population because adult fish today are less fertile than their ancestors.

“The big debate has been over whether this is an evolutionary response to the way they are fished or whether this is, for instance, just the amount of food in the sea having a short-term ecological effect. Our study underlined that evolution can happen on a short timescale and even small 1 to 2 per cent evolutionary changes in the underlying biology caused by your harvesting strategy can have major consequences on population growth and yields. You can’t just try to bring the environment back to what it was before and expect everything to return to normal,” Professor Benton said.

The research was funded by the Natural Environment Research Council (NERC) and involved researchers from the University of Leeds and Professor Stuart Piertney of the University of Aberdeen’s School of Biological Sciences.

Journal Reference:

  1. Tom C. Cameron, Daniel O’Sullivan, Alan Reynolds, Stuart B. Piertney, Tim G. Benton. Eco-evolutionary dynamics in response to selection on life-historyEcology Letters, 2013; DOI: 10.1111/ele.12107

The Ethics of Resurrecting Extinct Species (Science Daily)

Apr. 8, 2013 — At some point, scientists may be able to bring back extinct animals, and perhaps early humans, raising questions of ethics and environmental disruption.

Within a few decades, scientists may be able to bring back the dodo bird from extinction, a possibility that raises a host of ethical questions, says Stanford law Professor Hank Greely. (Credit: Frederick William Frohawk/Public domain image)

Within a few decades, scientists may be able to bring back the dodo bird from extinction, a possibility that raises a host of ethical questions, says Stanford law Professor Hank Greely.

Twenty years after the release ofJurassic Park, the dream of bringing back the dinosaurs remains science fiction. But scientists predict that within 15 years they will be able to revive some more recently extinct species, such as the dodo or the passenger pigeon, raising the question of whether or not they should — just because they can.

In the April 5 issue of Science, Stanford law Professor Hank Greely identifies the ethical landmines of this new concept of de-extinction.

“I view this piece as the first framing of the issues,” said Greely, director of the Stanford Center for Law and the Biosciences. “I don’t think it’s the end of the story, rather I think it’s the start of a discussion about how we should deal with de-extinction.”

In “What If Extinction Is Not Forever?” Greely lays out potential benefits of de-extinction, from creating new scientific knowledge to restoring lost ecosystems. But the biggest benefit, Greely believes, is the “wonder” factor.

“It would certainly be cool to see a living saber-toothed cat,” Greely said. “‘Wonder’ may not seem like a substantive benefit, but a lot of science — such as the Mars rover — is done because of it.”

Greely became interested in the ethics of de-extinction in 1999 when one of his students wrote a paper on the implications of bringing back wooly mammoths.

“He didn’t have his science right — which wasn’t his fault because approaches on how to do this have changed in the last 13 years — but it made me realize this was a really interesting topic,” Greely said.

Scientists are currently working on three different approaches to restore lost plants and animals. In cloning, scientists use genetic material from the extinct species to create an exact modern copy. Selective breeding tries to give a closely-related modern species the characteristics of its extinct relative. With genetic engineering, the DNA of a modern species is edited until it closely matches the extinct species.

All of these techniques would bring back only the physical animal or plant.

“If we bring the passenger pigeon back, there’s no reason to believe it will act the same way as it did in 1850,” said co-author Jacob Sherkow, a fellow at the Stanford Center for Law and the Biosciences. “Many traits are culturally learned. Migration patterns change when not taught from generation to generation.”

Many newly revived species could cause unexpected problems if brought into the modern world. A reintroduced species could become a carrier for a deadly disease or an unintentional threat to a nearby ecosystem, Greely says.

“It’s a little odd to consider these things ‘alien’ species because they were here before we were,” he said. “But the ‘here’ they were in is very different than it is now. They could turn out to be pests in this new environment.”

When asked whether government policies are keeping up with the new threat, Greely answers “no.”

“But that’s neither surprising nor particularly concerning,” he said. “It will be a while before any revised species is going to be present and able to be released into the environment.”

Greely and Sherkow recommend that the government leave de-extinction research to private companies and focus on drafting new regulations. Sherkow says the biggest legal and ethical challenge of de-extinction concerns our own long-lost ancestors.

“Bringing back a hominid raises the question, ‘Is it a person?’ If we bring back a mammoth or pigeon, there’s a very good existing ethical and legal framework for how to treat research animals. We don’t have very good ethical considerations of creating and keeping a person in a lab,” said Sherkow. “That’s a far cry from the type of de-extinction programs going on now, but it highlights the slippery slope problem that ethicists are famous for considering.”

Journal Reference:

  1. J. S. Sherkow, H. T. Greely. What If Extinction Is Not Forever? Science, 2013; 340 (6128): 32 DOI:10.1126/science.1236965

Controversial Worm Keeps Its Position as Progenitor of Humankind (Science Daily)

Xenoturbella bocki worm. (Credit: Hiroaki Nakano)

Mar. 27, 2013 — Researchers are arguing about whether or not the Xenoturbella bocki worm is the progenitor of humankind. But new studies indicate that this is actually the case.

Swedish researchers from the University of Gothenburg and the Gothenburg Natural History Museum are involved in the international study. The results have been published in Nature Communications.

The Xenoturbella bocki worm is a one-centimetre long worm with a simple body plan that is only found regularly by the west coast of Sweden. The worm lacks a brain, sexual organs and other vital organs.

Zoologists have long disagreed about whether or not the Xenoturbella bocki worm holds a key position in the animal tree of life. If it does have a key position, it is very important for the understanding of the evolutionary development of organs and cell functions, such as stem cells, for example. The question is therefore not only important in the field of biology, but also for potential biomedical applications.

“It’s absolutely fantastic that one of the key evolutionary organisms in the animal kingdom lives right on the doorstep of the University of Gothenburg’s Centre for Marine Research. And this is actually the only place in the whole world where you can do research on the creature,” says Matthias Obst from the Department of Biological and Environmental Sciences at the University of Gothenburg.

Genetic studies indicate that theXenoturbella bocki worm belongs to the group of deuterostomes, the exclusive group to which human’s belongs.

“So maybe we’re more closely related to the Xenoturbella bocki worm, which doesn’t have a brain, than we are to lobsters and flies, for example,” says Matthias Obst.

Even though the worm does not particularly resemble man, development biologists have referred to the fact that the early embryonic development of the worm may display similarities with the group to which man belongs. But the problem has been that no one has previously been able to see the development of the creature.

But now a group of researchers at the Sven Lovén Centre for Marine Sciences and the Gothenburg Natural History Museum have succeeded in doing what no one else has done before: to isolate newly born little Xenoturbella bocki worms.

“And these new-born worms revealed absolutely no remnants at all of advanced features! Instead, they exhibit similarities with quite simple, ancient animals such as corals and sponges,” says Matthias Obst.

The studies also reveal the value of the University of Gothenburg’s marine stations for important basic research.

“The Lovén Centre at the University of Gothenburg is the only place in the whole world where you can study this paradoxical animal (in Swedish called ‘Paradox worm’). That’s one reason why researchers come from all over the world to Gullmarsfjorden to solve one of the great mysteries in the evolution of animal life,” says Matthias Obst.

Journal Reference:

  1. Hiroaki Nakano, Kennet Lundin, Sarah J. Bourlat, Maximilian J. Telford, Peter Funch, Jens R. Nyengaard, Matthias Obst, Michael C. Thorndyke. Xenoturbella bocki exhibits direct development with similarities to AcoelomorphaNature Communications, 2013; 4: 1537 DOI: 10.1038/ncomms2556

Edward O. Wilson: The Riddle of the Human Species (N.Y.Times)

THE STONEFebruary 24, 2013, 7:30 pm

By EDWARD O. WILSON

The task of understanding humanity is too important and too daunting to leave to the humanities. Their many branches, from philosophy to law to history and the creative arts, have described the particularities of human nature with genius and exquisite detail, back and forth in endless permutations. But they have not explained why we possess our special nature and not some other out of a vast number of conceivable possibilities. In that sense, the humanities have not accounted for a full understanding of our species’ existence.

So, just what are we? The key to the great riddle lies in the circumstance and process that created our species. The human condition is a product of history, not just the six millenniums of civilization but very much further back, across hundreds of millenniums. The whole of it, biological and cultural evolution, in seamless unity, must be explored for an answer to the mystery. When thus viewed across its entire traverse, the history of humanity also becomes the key to learning how and why our species survived.

A majority of people prefer to interpret history as the unfolding of a supernatural design, to whose author we owe obedience. But that comforting interpretation has grown less supportable as knowledge of the real world has expanded. Scientific knowledge (measured by numbers of scientists and scientific journals) in particular has been doubling every 10 to 20 years for over a century. In traditional explanations of the past, religious creation stories have been blended with the humanities to attribute meaning to our species’s existence. It is time to consider what science might give to the humanities and the humanities to science in a common search for a more solidly grounded answer to the great riddle.

To begin, biologists have found that the biological origin of advanced social behavior in humans was similar to that occurring elsewhere in the animal kingdom. Using comparative studies of thousands of animal species, from insects to mammals, they have concluded that the most complex societies have arisen through eusociality — roughly, “true” social condition. The members of a eusocial group cooperatively rear the young across multiple generations. They also divide labor through the surrender by some members of at least some of their personal reproduction in a way that increases the “reproductive success” (lifetime reproduction) of other members.

Leif Parsons

Eusociality stands out as an oddity in a couple of ways. One is its extreme rarity. Out of hundreds of thousands of evolving lines of animals on the land during the past 400 million years, the condition, so far as we can determine, has arisen only about two dozen times. This is likely to be an underestimate, due to sampling error. Nevertheless, we can be certain that the number of originations was very small.

Furthermore, the known eusocial species arose very late in the history of life. It appears to have occurred not at all during the great Paleozoic diversification of insects, 350 to 250 million years before the present, during which the variety of insects approached that of today. Nor is there as yet any evidence of eusocial species during the Mesozoic Era until the appearance of the earliest termites and ants between 200 and 150 million years ago. Humans at the Homo level appeared only very recently, following tens of millions of years of evolution among the primates.

Once attained, advanced social behavior at the eusocial grade has proved a major ecological success. Of the two dozen independent lines, just two within the insects — ants and termites — globally dominate invertebrates on the land. Although they are represented by fewer than 20 thousand of the million known living insect species, ants and termites compose more than half of the world’s insect body weight.

The history of eusociality raises a question: given the enormous advantage it confers, why was this advanced form of social behavior so rare and long delayed? The answer appears to be the special sequence of preliminary evolutionary changes that must occur before the final step to eusociality can be taken. In all of the eusocial species analyzed to date, the final step before eusociality is the construction of a protected nest, from which foraging trips begin and within which the young are raised to maturity. The original nest builders can be a lone female, a mated pair, or a small and weakly organized group. When this final preliminary step is attained, all that is needed to create a eusocial colony is for the parents and offspring to stay at the nest and cooperate in raising additional generations of young. Such primitive assemblages then divide easily into risk-prone foragers and risk-averse parents and nurses.

Leif Parsons

What brought one primate line to the rare level of eusociality? Paleontologists have found that the circumstances were humble. In Africa about two million years ago, one species of the primarily vegetarian australopithecine evidently shifted its diet to include a much higher reliance on meat. For a group to harvest such a high-energy, widely dispersed source of food, it did not pay to roam about as a loosely organized pack of adults and young like present-day chimpanzees and bonobos. It was more efficient to occupy a campsite (thus, the nest) and send out hunters who could bring home meat, either killed or scavenged, to share with others. In exchange, the hunters received protection of the campsite and their own young offspring kept there.

From studies of modern humans, including hunter-gatherers, whose lives tell us so much about human origins, social psychologists have deduced the mental growth that began with hunting and campsites. A premium was placed on personal relationships geared to both competition and cooperation among the members. The process was ceaselessly dynamic and demanding. It far exceeded in intensity anything similar experienced by the roaming, loosely organized bands of most animal societies. It required a memory good enough to assess the intentions of fellow members, to predict their responses, from one moment to the next; and it resulted in the ability to invent and inwardly rehearse competing scenarios of future interactions.

The social intelligence of the campsite-anchored prehumans evolved as a kind of non-stop game of chess. Today, at the terminus of this evolutionary process, our immense memory banks are smoothly activated across the past, present, and future. They allow us to evaluate the prospects and consequences variously of alliances, bonding, sexual contact, rivalries, domination, deception, loyalty and betrayal. We instinctively delight in the telling of countless stories about others as players upon the inner stage. The best of it is expressed in the creative arts, political theory, and other higher-level activities we have come to call the humanities.

The definitive part of the long creation story evidently began with the primitive Homo habilis (or a species closely related to it) two million years ago. Prior to the habilines the prehumans had been animals. Largely vegetarians, they had human-like bodies, but their cranial capacity remained chimpanzee-size, at or below 500 cubic centimeters. Starting with the habiline period the capacity grew precipitously: to 680 cubic centimeters in Homo habilis, 900 in Homo erectus, and about 1,400 in Homo sapiens. The expansion of the human brain was one of the most rapid episodes of evolution of complex organs in the history of life.


Still, to recognize the rare coming together of cooperating primates is not enough to account for the full potential of modern humans that brain capacity provides. Evolutionary biologists have searched for the grandmaster of advanced social evolution, the combination of forces and environmental circumstances that bestowed greater longevity and more successful reproduction on the possession of high social intelligence. At present there are two competing theories of the principal force. The first is kin selection: individuals favor collateral kin (relatives other than offspring) making it easier for altruism to evolve among members of the same group. Altruism in turn engenders complex social organization, and, in the one case that involves big mammals, human-level intelligence.

The second, more recently argued theory (full disclosure: I am one of the modern version’s authors), the grandmaster is multilevel selection. This formulation recognizes two levels at which natural selection operates: individual selection based on competition and cooperation among members of the same group, and group selection, which arises from competition and cooperation between groups. Multilevel selection is gaining in favor among evolutionary biologists because of a recent mathematical proof that kin selection can arise only under special conditions that demonstrably do not exist, and the better fit of multilevel selection to all of the two dozen known animal cases of eusocial evolution.

The roles of both individual and group selection are indelibly stamped (to borrow a phrase from Charles Darwin) upon our social behavior. As expected, we are intensely interested in the minutiae of behavior of those around us. Gossip is a prevailing subject of conversation, everywhere from hunter-gatherer campsites to royal courts. The mind is a kaleidoscopically shifting map of others, each of whom is drawn emotionally in shades of trust, love, hatred, suspicion, admiration, envy and sociability. We are compulsively driven to create and belong to groups, variously nested, overlapping or separate, and large or small. Almost all groups compete with those of similar kind in some manner or other. We tend to think of our own as superior, and we find our identity within them.

The existence of competition and conflict, the latter often violent, has been a hallmark of societies as far back as archaeological evidence is able to offer. These and other traits we call human nature are so deeply resident in our emotions and habits of thought as to seem just part of some greater nature, like the air we all breathe, and the molecular machinery that drives all of life. But they are not. Instead, they are among the idiosyncratic hereditary traits that define our species.

The major features of the biological origins of our species are coming into focus, and with this clarification the potential of a more fruitful contact between science and the humanities. The convergence between these two great branches of learning will matter hugely when enough people have thought it through. On the science side, genetics, the brain sciences, evolutionary biology, and paleontology will be seen in a different light. Students will be taught prehistory as well as conventional history, the whole presented as the living world’s greatest epic.

We will also, I believe, take a more serious look at our place in nature. Exalted we are indeed, risen to be the mind of the biosphere without a doubt, our spirits capable of awe and ever more breathtaking leaps of imagination. But we are still part of earth’s fauna and flora. We are bound to it by emotion, physiology, and not least, deep history. It is dangerous to think of this planet as a way station to a better world, or continue to convert it into a literal, human-engineered spaceship. Contrary to general opinion, demons and gods do not vie for our allegiance. We are self-made, independent, alone and fragile. Self-understanding is what counts for long-term survival, both for individuals and for the species.

Edward O. Wilson is Honorary Curator in Entomology and University Research Professor Emeritus, Harvard University. He has received more than 100 awards for his research and writing, including the U. S. National Medal of Science, the Crafoord Prize and two Pulitzer Prizes in non-fiction. His most recent book is “The Social Conquest of Earth.”

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Interview with Edward O. Wilson: The Origin of Morals (Spiegel)

February 26, 2013 – 01:23 PM

By Philip Bethge and Johann Grolle

American sociobiologist Edward O. Wilson is championing a controversial new approach for explaining the origins of virtue and sin. In an interview, the world-famous ant reseacher explains why he believes the inner struggle is the characteristic trait of human nature.

Edward O. Wilson doesn’t come across as the kind of man who’s looking to pick a fight. With his shoulders upright and his head tilting slightly to the side, he shuffles through the halls of Harvard University. His right eye, which has given him trouble since his childhood, is halfway closed. The other is fixed on the ground. As an ant researcher, Wilson has made a career out of things that live on the earth’s surface.

There’s also much more to Wilson. Some consider him to be the world’s most important living biologist, with some placing him on a level with Charles Darwin.

In addition to discovering and describing hundreds of species of ants, Wilson’s book on this incomparably successful group of insects is the only non-fiction biology tome ever to win a Pulitzer Prize. Another achievement was decoding the chemical communication of ants, whose vocabulary is composed of pheromones. His study of the ant colonization of islands helped to establish one of the most fruitful branches of ecology. And when it comes to the battle against the loss of biodiversity, Wilson is one of the movement’s most eloquent voices.

‘Blessed with Brilliant Enemies’

But Wilson’s fame isn’t solely the product of his scientific achievements. His enemies have also helped him to establish a name. “I have been blessed with brilliant enemies,” he says. In fact, the multitude of scholars with whom Wilson has skirmished academically is illustrious. James Watson, one of the discoverers of the double helix in DNA is among them, as is essayist Stephen Jay Gould.

At 83 years of age, Wilson is still at work making a few new enemies. The latest source of uproar is a book, “The Social Conquest of Earth,” published last April in the United States and this month in a German-language edition. In the tome, Wilson attempts to describe the triumphal advance of humans in evolutionary terms.

It is not uncommon for Wilson to look to ants for inspiration in his writings — and that proves true here, as well. When, for example, he recalls beholding two 90-million-year-old worker ants that were trapped in a piece of fossil metasequoia amber as being “among the most exciting moments in my life,” a discovery that “ranked in scientific importance withArchaeopteryx, the first fossil intermediary between birds and dinosaurs, and Australopithecus, the first ‘missing link’ discovered between modern humans and the ancestral apes.”

But that’s all just foreplay to the real controversy at the book’s core. Ultimately, Wilson uses ants to explain humans’ social behavior and, by doing so, breaks with current convention. The key question is the level at which Darwinian selection of human characteristics takes place. Did individuals enter into a fight for survival against each other, or did groups battle it out against competing groups?

Prior to this book, Wilson had been an influential champion of the theory of kin selection. He has now rejected his previous teachings, literally demolishing them. “The beautiful theory never worked well anyway, and now it has collapsed,” he writes. Today, he argues that human nature can only be understood if it is perceived as being the product of “group selection” — a view that Wilson’s fellow academics equate with sacrilege. They literally lined up to express their scientific dissent in a joint letter.

Some of the most vociferous criticism has come from Richard Dawkins, whose bestselling 1976 book “The Selfish Gene” first introduced the theory of kin selection to a mass audience. In a withering review of Wilson’s book in Britain’s Prospect magazine, Dawkins accuses a man he describes as his “lifelong hero” of “wanton arrogance” and “perverse misunderstandings”. “To borrow from Dorothy Parker,” he writes, “this is not a book to be tossed lightly aside. It should be thrown with great force.”

SPIEGEL recently sat down with sociobiologist Wilson to discuss his book and the controversy surrounding it.

SPIEGEL: Professor Wilson, lets assume that 10 million years ago some alien spacecraft had landed on this planet. Which organisms would they find particularly intriguing?

Wilson: Their interest, I believe, would not have been our ancestors. Primarily, they would have focused on ants, bees, wasps, and termites. Their discovery is what the aliens would report back to headquarters.

SPIEGEL: And you think those insects would be more interesting to them than, for example, elephants, flocks of birds or intelligent primates?

Wilson: They would be, because, at that time, ants and termites would be the most abundant creatures on the land and the most highly social creatures with very advanced division of labor and caste. We call them “eusocial,” and this phenomenon seems to be extremely rare.

SPIEGEL: What else might the aliens consider particularly interesting about ants?

Wilson: Ants engage in farming and animal husbandry. For example, some of them cultivate fungi. Others herd aphids and literally milk them by stroking them with their antennae. And the other thing the aliens would find extremely interesting would be the degree to which these insects organize their societies by pheromones, by chemical communication. Ants and termites have taken this form of communication to extremes.

SPIEGEL: So the aliens would cable back home: “We have found ants. They are the most promising candidates for a future evolution towards intelligent beings on earth?”

Wilson: No, they wouldn’t. They would see that these creatures were encased in exoskeletons and therefore had to remain very small. They would conclude that there was little chance for individual ants or termites to develop much reasoning power, nor, as a result, the capacity for culture. But at least on this planet, you have to be big in order to have sufficient cerebral cortex. And you probably have to be bipedal and develop hands with pulpy fingers, because those give you the capacity to start creating objects and to manipulate the environment.

SPIEGEL: Would our ancestors not have caught their eye?

Wilson: Ten million years ago, our ancestors indeed had developed a somewhat larger brain and versatile hands already. But the crucial step had yet to come.

SPIEGEL: What do you mean?

Wilson: Let me go back to the social insects for a moment. Why did social insects start to form colonies? Across hundreds of millions of years, insects had been proliferating as solitary forms. Some of them stayed with their young for a while, guided them and protected them. You find that widespread but far from universal in the animal kingdom. However, out of those species came a much smaller number of species who didn’t just protect their young, but started building nests that they defended …

SPIEGEL: … similar to birds.

Wilson: Yes. And I think that birds are right at the threshold of eusocial behaviour. But looking at the evolution of ants and termites again, there is another crucial step. In an even smaller group, the young don’t only grow up in their nest, but they also stay and care for the next generation. Now you have a group staying together with a division of labor. That is evidently the narrow channel of evolution that you have to pass through in order to become eusocial.

SPIEGEL: And our ancestors followed the same path?

Wilson: Yes. I argue that Homo habilis, the first humans, also went through these stages. In particular, Homo habilis was unique in that they already had shifted to eating meat.

SPIEGEL: What difference would that make?

Wilson: When animals start eating meat, they tend to form packs and to divide labor. We know that the immediate descendants of Homo habilis, Homo erectus, gathered around camp sites and that they actually had begun to use fire. These camp sites are equivalent to nests. That’s where they gathered in a tightly knit group, and then individuals went out searching for food.

SPIEGEL: And this development of groups drives evolution even further?

Wilson: Exactly. And, for example, if it now comes to staking out the hunting grounds, then group stands against group.

SPIEGEL: Meaning that this is the origin of warfare?

Wilson: Yes. But it doesn’t take necessarily the forming of an army or a battalion and meeting on the field and fighting. It was mostly what you call “vengeance raids”. One group attacks another, maybe captures a female or kills one or two males. The other group then counterraids, and this will go back and forth, group against group.

SPIEGEL: You say that this so called group selection is vital for the evolution of humans. Yet traditionally, scientists explain the emergence of social behavior in humans by kin selection.

Wilson: That, for a number of reasons, isn’t much good as an explanation.

SPIEGEL: But you yourself have long been a proponent of this theory. Why did you change your mind?

Wilson: You are right. During the 1970s, I was one of the main proponents of kin selection theory. And at first the idea sounds very reasonable. So for example, if I favored you because you were my brother and therefore we share one half of our genes, then I could sacrifice a lot for you. I could give up my chance to have children in order to get you through college and have a big family. The problem is: If you think it through, kin selection doesn’t explain anything. Instead, I came to the conclusion that selection operates on multiple levels. On one hand, you have normal Darwinian selection going on all the time, where individuals compete with each other. In addition, however, these individuals now form groups. They are staying together, and consequently it is group versus group.

SPIEGEL: Turning away from kin selection provoked a rather fierce reaction from many of your colleagues.

Wilson: No, it didn’t. The reaction was strong, but it came from a relatively small group of people whose careers are based upon studies of kin selection.

SPIEGEL: Isn’t that too easy? After all, 137 scientists signed a response to your claims. They accuse you of a “misunderstanding of evolutionary theory”.

Wilson: You know, most scientists are tribalists. Their lives are so tied up in certain theories that they can’t let go.

SPIEGEL: Does it even make a substantial difference if humans evolved through kin selection or group selection?

Wilson: Oh, it changes everything. Only the understanding of evolution offers a chance to get a real understanding of the human species. We are determined by the interplay between individual and group selection where individual selection is responsible for much of what we call sin, while group selection is responsible for the greater part of virtue. We’re all in constant conflict between self-sacrifice for the group on the one hand and egoism and selfishness on the other. I go so far as to say that all the subjects of humanities, from law to the creative arts are based upon this play of individual versus group selection.

SPIEGEL: Is this Janus-faced nature of humans our greatest strength at the end of the day?

Wilson: Exactly. This inner conflict between altruism and selfishness is the human condition. And it is very creative and probably the source of our striving, our inventiveness and imagination. It’s that eternal conflict that makes us unique.

SPIEGEL: So how do we negotiate this conflict?

Wilson: We don’t. We have to live with it.

SPIEGEL: Which element of this human condition is stronger?

Wilson: Let’s put it this way: If we would be mainly influenced by group selection, we would be living in kind of an ant society.

SPIEGEL: … the ultimate form of communism?

Wilson: Yes. Once in a while, humans form societies that emphasize the group, for example societies with Marxist ideology. But the opposite is also true. In other societies the individual is everything. Politically, that would be the Republican far right.

SPIEGEL: What determines which ideology is predominant in a society?

Wilson: If your territory is invaded, then cooperation within the group will be extreme. That’s a human instinct. If you are in a frontier area, however, then we tend to move towards the extreme individual level. That seems to be a good part of the problem still with America. We still think we’re on the frontier, so we constantly try to put forward individual initiative and individual rights and rewards based upon individual achievement.

SPIEGEL: Earlier, you differentiated between the “virtue” of altruism and the “sin” of individualism. In your book you talk about the “poorer and the better angels” of human nature. Is it helpful to use this kind of terminology?

Wilson: I will admit that using the terminology of “virtue” and “sin” is what poets call a “trope”. That is to say, I wanted the idea in crude form to take hold. Still, a lot of what we call “virtue” has to do with propensities to behave well toward others. What we call “sin” are things that people do mainly out of self-interest.

SPIEGEL: However, our virtues towards others go only so far. Outside groups are mainly greeted with hostility.

Wilson: You are right. People have to belong to a group. That’s one of the strongest propensities in the human psyche and you won’t be able to change that. However, I think we are evolving, so as to avoid war — but without giving up the joy of competition between groups. Take soccer …

SPIEGEL: … or American football.

Wilson: Oh, yes, American football, it’s a blood sport. And people live by team sports and national or regional pride connected with team sports. And that’s what we should be aiming for, because, again, that spirit is one of the most creative. It landed us on the moon, and people get so much pleasure from it. I don’t want to see any of that disturbed. That is a part of being human. We need our big games, our team sports, our competition, our Olympics.

SPIEGEL: “Humans,” the saying goes, “have Paleolithic emotions” …

Wilson: … “Medieval institutions and god-like technology”. That’s our situation, yeah. And we really have to handle that.

SPIEGEL: How?

Wilson: So often it happens that we don’t know how, also in situations of public policy and governance, because we don’t have enough understanding of human nature. We simply haven’t looked at human nature in the best way that science might provide. I think what we need is a new Enlightenment. During the 18th century, when the original Enlightenment took place, science wasn’t up to the job. But I think science is now up to the job. We need to be harnessing our scientific knowledge now to get a better, science-based self-understanding.

SPIEGEL: It seems that, in this process, you would like to throw religions overboard altogether?

Wilson: No. That’s a misunderstanding. I don’t want to see the Catholic Church with all of its magnificent art and rituals and music disappear. I just want to have them give up their creation stories, including especially the resurrection of Christ.

SPIEGEL: That might well be a futile endeavour …

Wilson: There was this American physiologist who was asked if Mary’s bodily ascent from Earth to Heaven was possible. He said, “I wasn’t there; therefore, I’m not positive that it happened or didn’t happen; but of one thing I’m certain: She passed out at 10,000 meters.” That’s where science comes in. Seriously, I think we’re better off with no creation stories.

SPIEGEL: With this new Enlightenment, will we reach a higher state of humanity?

Wilson: Do we really want to improve ourselves? Humans are a very young species, in geologic terms, and that’s probably why we’re such a mess. We’re still living with all this aggression and ability to go to war. But do we really want to change ourselves? We’re right on the edge of an era of being able to actually alter the human genome. But do we want that? Do we want to create a race that’s more rational and free of many of these emotions? My response is no, because the only thing that distinguishes us from super-intelligent robots are our imperfect, sloppy, maybe even dangerous emotions. They are what makes us human.

SPIEGEL: Mr. Wilson, we thank you for this conversation.

Interview conducted by Philip Bethge and Johann Grolle

Fluctuating Environment May Have Driven Human Evolution (Science Daily)

Dec. 24, 2012 — A series of rapid environmental changes in East Africa roughly 2 million years ago may be responsible for driving human evolution, according to researchers at Penn State and Rutgers University.

“The landscape early humans were inhabiting transitioned rapidly back and forth between a closed woodland and an open grassland about five to six times during a period of 200,000 years,” said Clayton Magill, graduate student in geosciences at Penn State. “These changes happened very abruptly, with each transition occurring over hundreds to just a few thousand years.”

According to Katherine Freeman, professor of geosciences, Penn State, the current leading hypothesis suggests that evolutionary changes among humans during the period the team investigated were related to a long, steady environmental change or even one big change in climate.

“There is a view this time in Africa was the ‘Great Drying,’ when the environment slowly dried out over 3 million years,” she said. “But our data show that it was not a grand progression towards dry; the environment was highly variable.”

According to Magill, many anthropologists believe that variability of experience can trigger cognitive development.

“Early humans went from having trees available to having only grasses available in just 10 to 100 generations, and their diets would have had to change in response,” he said. “Changes in food availability, food type, or the way you get food can trigger evolutionary mechanisms to deal with those changes. The result can be increased brain size and cognition, changes in locomotion and even social changes — how you interact with others in a group. Our data are consistent with these hypotheses. We show that the environment changed dramatically over a short time, and this variability coincides with an important period in our human evolution when the genus Homo was first established and when there was first evidence of tool use.”

The researchers — including Gail Ashley, professor of earth and planetary sciences, Rutgers University — examined lake sediments from Olduvai Gorge in northern Tanzania. They removed the organic matter that had either washed or was blown into the lake from the surrounding vegetation, microbes and other organisms 2 million years ago from the sediments. In particular, they looked at biomarkers — fossil molecules from ancient organisms — from the waxy coating on plant leaves.

“We looked at leaf waxes because they’re tough, they survive well in the sediment,” said Freeman.

The team used gas chromatography and mass spectrometry to determine the relative abundances of different leaf waxes and the abundance of carbon isotopes for different leaf waxes. The data enabled them to reconstruct the types of vegetation present in the Olduvai Gorge area at very specific time intervals.

The results showed that the environment transitioned rapidly back and forth between a closed woodland and an open grassland.

To find out what caused this rapid transitioning, the researchers used statistical and mathematical models to correlate the changes they saw in the environment with other things that may have been happening at the time, including changes in the Earth’s movement and changes in sea-surface temperatures.

“The orbit of the Earth around the sun slowly changes with time,” said Freeman. “These changes were tied to the local climate at Olduvai Gorge through changes in the monsoon system in Africa. Slight changes in the amount of sunshine changed the intensity of atmospheric circulation and the supply of water. The rain patterns that drive the plant patterns follow this monsoon circulation. We found a correlation between changes in the environment and planetary movement.”

The team also found a correlation between changes in the environment and sea-surface temperature in the tropics.

“We find complementary forcing mechanisms: one is the way Earth orbits, and the other is variation in ocean temperatures surrounding Africa,” Freeman said. The researchers recently published their results in the Proceedings of the National Academy of Sciences along with another paper in the same issue that builds on these findings. The second paper shows that rainfall was greater when there were trees around and less when there was a grassland.

“The research points to the importance of water in an arid landscape like Africa,” said Magill. “The plants are so intimately tied to the water that if you have water shortages, they usually lead to food insecurity.

“Together, these two papers shine light on human evolution because we now have an adaptive perspective. We understand, at least to a first approximation, what kinds of conditions were prevalent in that area and we show that changes in food and water were linked to major evolutionary changes.”

The National Science Foundation funded this research.

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How climate shifts in Africa sparked human evolution (MSNBC)

Scientists say landscape transitions may have forced early humans to think on their feet

Image: Nutcracker Man

Nicolle Rager Fuller / NSF. The first specimen of Paranthropus boisei, also called Nutcracker Man, was reported by Mary and Louis Leakey in 1959 from a site in Olduvai Gorge, Tanzania.

By Charles Choi – LiveScience Contributor

updated 12/26/2012 2:16:27 PM ET

At Olduvai Gorge, where excavations helped to confirm Africa was the cradle of humanity, scientists now find the landscape once fluctuated rapidly, likely guiding early human evolution.

These findings suggest that key mental developments within the human lineage may have been linked with a highly variable environment, researchers added.

Olduvai Gorge is a ravine cut into the eastern margin of the Serengeti Plain in northern Tanzania that holds fossils of hominins — members of the human lineage. Excavations at Olduvai Gorge by Louis and Mary Leakey in the mid-1950s helped to establish the African origin of humanity.

The Great Drying? 

To learn more about the roots of humanity, scientists analyzed samples of leaf waxes preserved in lake sediments at Olduvai Gorge, identifying which plants dominated the local environment around 2 million years ago. This was about when Homo erectus, a direct ancestor of modern humans who used relatively advanced stone tools, appeared.

“We looked at leaf waxes, because they’re tough, they survive well in the sediment,” researcher Katherine Freeman, a biogeochemist at Pennsylvania State University, said in a statement.

After four years of work, the researchers focused on carbon isotopes — atoms of the same element with different numbers of neutrons — in the samples, which can reveal what plants reigned over an area. The grasses that dominate savannas engage in a kind of photosynthesis that involves both normal carbon-12 and heavier carbon-13, while trees and shrubs rely on a kind of photosynthesis that prefers carbon-12. (Atoms of carbon-12 each possess six neutrons, while atoms of carbon-13 have seven.)

Scientists had long thought Africa went through a period of gradually increasing dryness — called the Great Drying — over 3 million years, or perhaps one big change in climate that favored the expansion of grasslands across the continent, influencing human evolution. However, the new research instead revealed “strong evidence for dramatic ecosystem changes across the African savanna, in which open grassland landscapes transitioned to closed forests over just hundreds to several thousands of years,” researcher Clayton Magill, a biogeochemist at Pennsylvania State University, told LiveScience. [Know Your Roots? Take Our Human Evolution Quiz]

The researchers discovered that Olduvai Gorge abruptly and routinely fluctuated between dry grasslands and damp forests about five or six times during a period of 200,000 years.

“I was surprised by the magnitude of changes and the rapid pace of the changes we found,” Freeman told LiveScience. “There was a complete restructuring of the ecosystem from grassland to forest and back again, at least based on how we interpret the data. I’ve worked on carbon isotopes my whole career, and I’ve never seen anything like this before.”

Losing water 

The investigators also constructed a highly detailed record of water history in Olduvai Gorge by analyzing hydrogen isotope ratios in plant waxes and other compounds in nearby lake sediments. These findings support the carbon isotope data, suggesting the region experienced fluctuations in aridity, with dry periods dominated by grasslands and wet periods characterized by expanses of woody cover.

“The research points to the importance of water in an arid landscape like Africa,” Magill said in a statement. “The plants are so intimately tied to the water that if you have water shortages, they usually lead to food insecurity.”

The research team’s statistical and mathematical models link the changes they see with other events at the time, such as alterations in the planet’s movement. [50 Amazing Facts About Earth]

“The orbit of the Earth around the sun slowly changes with time,” Freeman said in statement. “These changes were tied to the local climate at Olduvai Gorge through changes in the monsoon system in Africa.”

Earth’s orbit around the sun can vary over time in a number of ways — for instance,Earth’s orbit around the sun can grow more or less circular over time, and Earth’s axis of spin relative to the sun’s equatorial plane can also tilt back and forth. This alters the amount of sunlight Earth receives, energy that drives Earth’s atmosphere.

“Slight changes in the amount of sunshine changed the intensity of atmospheric circulation and the supply of water,” Freeman said. “The rain patterns that drive the plant patterns follow this monsoon circulation. We found a correlation between changes in the environment and planetary movement.”

The team also found links between changes at Olduvai Gorge and sea-surface temperatures in the tropics.

“We find complementary forcing mechanisms — one is the way Earth orbits, and the other is variation in ocean temperatures surrounding Africa,” Freeman said.

These findings now shed light on the environmental shifts the ancestors of modern humans might have had to adapt to in order to survive and thrive.

“Early humans went from having trees available to having only grasses available in just 10 to 100 generations, and their diets would have had to change in response,” Magill said in a statement. “Changes in food availability, food type, or the way you get food can trigger evolutionary mechanisms to deal with those changes. The result can be increased brain size and cognition, changes in locomotion and even social changes — how you interact with others in a group.”

This variability in the environment coincided with a key period in human evolution, “when the genus Homo was first established and when there was first evidence of tool use,” Magill said.

The researchers now hope to examine changes at Olduvai Gorge not just across time but space, which could help shed light on aspects of early human evolution such as foraging patterns.

Magill, Freeman and their colleague Gail Ashley detailed their findings online Dec. 24 in two papers in the Proceedings of the National Academy of Sciences.

Origin of intelligence and mental illness linked to ancient genetic accident (University of Edinburgh)

2-Dec-2012 – By Tara Womersley, University of Edinburgh

Scientists have discovered for the first time how humans – and other mammals – have evolved to have intelligence

Scientists have discovered for the first time how humans – and other mammals – have evolved to have intelligence.

Researchers have identified the moment in history when the genes that enabled us to think and reason evolved.

This point 500 million years ago provided our ability to learn complex skills, analyse situations and have flexibility in the way in which we think.

Professor Seth Grant, of the University of Edinburgh, who led the research, said: “One of the greatest scientific problems is to explain how intelligence and complex behaviours arose during evolution.”

The research, which is detailed in two papers in Nature Neuroscience, also shows a direct link between the evolution of behaviour and the origins of brain diseases.

Scientists believe that the same genes that improved our mental capacity are also responsible for a number of brain disorders.

“This ground breaking work has implications for how we understand the emergence of psychiatric disorders and will offer new avenues for the development of new treatments,” said John Williams, Head of Neuroscience and Mental Health at the Wellcome Trust, one of the study funders.

The study shows that intelligence in humans developed as the result of an increase in the number of brain genes in our evolutionary ancestors.

The researchers suggest that a simple invertebrate animal living in the sea 500 million years ago experienced a ‘genetic accident’, which resulted in extra copies of these genes being made.

This animal’s descendants benefited from these extra genes, leading to behaviourally sophisticated vertebrates – including humans.

The research team studied the mental abilities of mice and humans, using comparative tasks that involved identifying objects on touch-screen computers.

Researchers then combined results of these behavioural tests with information from the genetic codes of various species to work out when different behaviours evolved.

They found that higher mental functions in humans and mice were controlled by the same genes.

The study also showed that when these genes were mutated or damaged, they impaired higher mental functions.

“Our work shows that the price of higher intelligence and more complex behaviours is more mental illness,” said Professor Grant.

The researchers had previously shown that more than 100 childhood and adult brain diseases are caused by gene mutations.

“We can now apply genetics and behavioural testing to help patients with these diseases”, said Dr Tim Bussey from Cambridge University, which was also involved in the study.

The study was funded by the Wellcome Trust, the Medical Research Council and European Union.

Human intelligence ‘peaked thousands of years ago and we’ve been on an intellectual and emotional decline ever since’ (The Independent)

STEVE CONNOR, MONDAY 12 NOVEMBER 2012

Richard Gardner/Rex Features

Is the human species doomed to intellectual decline? Will our intelligence ebb away in centuries to come leaving our descendants incapable of using the technology their ancestors invented? In short: will Homo be left without his sapiens?

This is the controversial hypothesis of a leading geneticist who believes that the immense capacity of the human brain to learn new tricks is under attack from an array of genetic mutations that have accumulated since people started living in cities a few thousand years ago.

Professor Gerald Crabtree, who heads a genetics laboratory at Stanford University in California, has put forward the iconoclastic idea that rather than getting cleverer, human intelligence peaked several thousand years ago and from then on there has been a slow decline in our intellectual and emotional abilities.

Although we are now surrounded by the technological and medical benefits of a scientific revolution, these have masked an underlying decline in brain power which is set to continue into the future leading to the ultimate dumbing-down of the human species, Professor Crabtree said.

His argument is based on the fact that for more than 99 per cent of human evolutionary history, we have lived as hunter-gatherer communities surviving on our wits, leading to big-brained humans. Since the invention of agriculture and cities, however, natural selection on our intellect has effective stopped and mutations have accumulated in the critical “intelligence” genes.

“I would wager that if an average citizen from Athens of 1000BC were to appear suddenly among us, he or she would be among the brightest and most intellectually alive of our colleagues and companions, with a good memory, a broad range of ideas and a clear-sighted view of important issues,” Professor Crabtree says in a provocative paper published in the journal Trends in Genetics.

“Furthermore, I would guess that he or she would be among the most emotionally stable of our friends and colleagues. I would also make this wager for the ancient inhabitants of Africa, Asia, India or the Americas, of perhaps 2,000 to 6,000 years ago,” Professor Crabtree says.

“The basis for my wager comes from new developments in genetics, anthropology, and neurobiology that make a clear prediction that our intellectual and emotional abilities are genetically surprisingly fragile,” he says.

A comparison of the genomes of parents and children has revealed that on average there are between 25 and 65 new mutations occurring in the DNA of each generation. Professor Crabtree says that this analysis predicts about 5,000 new mutations in the past 120 generations, which covers a span of about 3,000 years.

Some of these mutations, he suggests, will occur within the 2,000 to 5,000 genes that are involved in human intellectual ability, for instance by building and mapping the billions of nerve cells of the brain or producing the dozens of chemical neurotransmitters that control the junctions between these brain cells.

Life as a hunter-gatherer was probably more intellectually demanding than widely supposed, he says. “A hunter-gatherer who did not correctly conceive a solution to providing food or shelter probably died, along with his or her progeny, whereas a modern Wall Street executive that made a similar conceptual mistake would receive a substantial bonus and be a more attractive mate,” Professor Crabtree says.

However, other scientists remain sceptical. “At first sight this is a classic case of Arts Faculty science. Never mind the hypothesis, give me the data, and there aren’t any,” said Professor Steve Jones, a geneticist at University College London.

“I could just as well argue that mutations have reduced our aggression, our depression and our penis length but no journal would publish that. Why do they publish this?” Professor Jones said.

“I am an advocate of Gradgrind science – facts, facts and more facts; but we need ideas too, and this is an ideas paper although I have no idea how the idea could be tested,” he said.

THE DESCENT OF MAN

Hunter-gatherer man

The human brain and its immense capacity for knowledge evolved during this long period of prehistory when we battled against the elements

Athenian man

The invention of agriculture less than 10,000 years ago and the subsequent rise of cities such as Athens relaxed the intensive natural selection of our “intelligence genes”.

Couch-potato man

As genetic mutations increase over future generations, are we doomed to watching  soap-opera repeats without knowing how to use the TV remote control?

iPad man

The fruits of science and technology enabled humans to rise above the constraints of nature and cushioned our fragile intellect from genetic mutations.