Max Planck Institute for Evolutionary Anthropology
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Contact: Sandra Jacob (e-mail: info@[>>> Please remove the brackets! <<<]eva.mpg.de, phone: +49 (0) 341-3550 122)
Sexual swellings are unreliable signals of fertility in female bonobos
In several species of primates, males often discern when to mate with a female based on cyclical changes in the size and firmness of her sexual swelling – a visual signal of a female’s probability to conceive. In a study of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, primatologist Pamela Heidi Douglas and colleagues investigated for the first time the relationship between ovarian hormones and sexual swellings in wild female bonobos. The likelihood that a female bonobo ovulates during her maximum swelling phase is much lower than in the closely related chimpanzees. Swellings are thus no reliable fertility signal for males and allow females to follow their own agenda when choosing a mate.
Our closest relatives were born with wide bodies and robust bones
If a Neandertal were to sit down next to us on the underground, we would probably first notice his receding forehead, prominent brow ridges and projecting, chinless face. Only on closer inspection would we notice his wider and thicker body. Researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig have now investigated whether the differences in physique between Neandertals and modern humans are genetic or caused by differences in lifestyle. Their analysis of two well-preserved skeletons of Neandertal neonates shows that Neandertals’ wide bodies and robust bones were formed by birth.
Researchers paint a genetic portrait of Ice Age Europe
By analyzing genome-wide data from the remains of 51 humans who lived between 45,000 and 7,000 years ago, an international research team has provided the first vivid look at the genetic history of modern humans in Europe before the introduction of farming. The team’s findings, published May 2 in Nature, reveal the disappearance and reappearance of a group that formed part of the ancestry of today’s Europeans, describe when and how Europeans acquired DNA from people in the Near East and show that the amount of Neanderthal DNA in modern human genomes has shrunk over the millennia, likely because the DNA was evolutionarily disadvantageous.
Five-year-olds affect the reputation of others through gossip
When it comes to selecting a cooperation partner, information about another person’s reputation – for example as a generous person or a miser – may come handy. Many animal species make reputation judgements, but only humans use gossip to pass on evaluative social information about others. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, show that five-year-olds but not three-year-olds reliably engage in such prosocial gossip.
Tooth-marks on a 500,000-year-old femur from Morocco indicate hominin hunting or scavenging by large carnivores
An international team of researchers including Camille Daujeard of the Muséum National D'Histoire Naturelle in Paris, France, and Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, analyzed tooth-marks on a 500,000-year-old hominin femur bone from a Moroccan cave and found that it had been consumed by large carnivores, likely hyenas.
Researchers find differences between ethnic groups living as farmers and those engaged in traditional hunter-gatherer activities
Scientists have long thought that the rate with which mutations occur in the genome does not depend on cultural factors. The results of a current study suggest this may not be the case. A team of researchers from France and Germany analysed more than 500 sequences of the male Y-chromosome in southern African ethnic groups living as farmers and in population groups engaged in traditional hunter-gatherer activities. The study found that the agriculturalists had a comparatively higher rate of change than the hunter-gatherers did. The researchers explain this by the significantly older average age of paternity among the agriculturalists. Furthermore, the study finds a much older age for the most recent common ancestor of the human Y-chromosome than was previously assumed.
More local adaptations in European genes were contributed by Stone Age hunters than farmers
Modern humans have adapted to their local environments over many thousands of years, but how genetic variation contributed to this adaptation remains debated. Using genomes from humans that lived between 45,000 and 7,000 years ago, researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig have shown that adaptation to local environments has resulted in genetic variants reaching high frequencies in European groups. Interestingly, most of the adaptive variants were present already in an early hunter-gatherer, but not in an early farmer. This suggests that hunter-gatherers, who lived in Europe for thousands of years before the arrival of farmers, were adapted to local environments and contributed adaptive genetic variants to present-day Europeans.
Analysis of nuclear DNA from Sima de los Huesos hominins provides evidence of their relationship to Neandertals
Previous analyses of the hominins from Sima de los Huesos in 2013 showed that their maternally inherited mitochondrial DNA was distantly related to Denisovans, extinct relatives of Neandertals in Asia. This was unexpected since their skeletal remains carry Neandertal-derived features. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have since worked on sequencing nuclear DNA from fossils from the cave, a challenging task as the extremely old DNA is degraded to very short fragments. The results now show that the Sima de los Huesos hominins were indeed early Neandertals. Neandertals may have acquired different mitochondrial genomes later, perhaps as the result of gene flow from Africa.
More Sumatran orangutans live in the wild than previously thought, yet continuing deforestation is likely to substantially reduce their number
Sumatran orangutans, one of the two existing species of orangutans, live exclusively in the North of the Indonesian island Sumatra and are critically endangered. This great ape is threatened by poaching and forest loss, as its habitat is being converted for agricultural purposes. An international team of researchers has now conducted an extensive series of surveys to estimate the number of Sumatran orangutans and discovered that about 14,600 of these animals still live in the wild today – 8,000 more than previously thought. Good news, however, the increase in numbers is due to a more wide-ranging survey effort and not to an increase in the orangutan population. Moreover, should the deforestation of the orangs’ habitat go ahead as planned, as many as 4,500 individuals could vanish by 2030. The researchers thus urge Sumatran national and provincial legislations to implement measures to avoid negative impacts on forests where orangutans occur.
Newly discovered stone tool-use behavior and accumulation sites in wild chimpanzees reminiscent to human cairns
Chimpanzees often use tools to extract or consume food. Which tools they choose for which purpose, however, can differ depending on the region where they live. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have thus initiated the ‘Pan African Programme: The Cultured Chimpanzee’ and, since 2010, have collected data on chimpanzee behavior, demography and resource availability across Africa following a standardized protocol. This is how the researchers encountered a thus far unknown behavior: In West Africa chimpanzees throw stones at trees resulting in conspicuous accumulations at these sites. Why exactly the animals do this the researchers do not yet know, yet the behavior appears to have some cultural elements.
Reintroduction of genetically distinct subspecies has led to hybridization in an endangered wild population
As their natural habitats continue to be destroyed, increasing numbers of displaced endangered mammals are taken to sanctuaries and rehabilitation centres worldwide. The ultimate goal of these centres is often reintroduction: to return these animals to wild populations. In a new study published today in Scientific Reports, however, Graham L Banes and Linda Vigilant of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, caution that such reintroductions can act as a form of genetic translocation. By using genetic analysis to assess a subset of historical reintroductions into Tanjung Puting National Park, Indonesia, they found that orang-utans from a non-native and genetically distinct subspecies were unwittingly released and have since hybridized with the Park’s wild population. As orang-utan subspecies are thought to have diverged around 176,000 years ago, with marked differentiation over the last 80,000 years, the researchers highlight the potential for negative effects on the viability of populations already under threat.
Researchers find evolution of human teeth to be much simpler than previously thought, and can predict the sizes of teeth missing from hominin fossils
A new study led by evolutionary biologist Alistair Evans of Monash University in Australia, took a fresh look at the teeth of humans and fossil hominins. The research confirms that molars, including ‘wisdom teeth’ do follow the sizes predicted by what is called ‘the inhibitory cascade’ – a rule that shows how the size of one tooth affects the size of the tooth next to it. This is important because it indicates that human evolution was a lot simpler than scientists had previously thought. The international team included researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
Researchers find first genetic evidence of modern human DNA in a Neanderthal individual
Using several different methods of DNA analysis, an international research team has identified an interbreeding event between Neanderthals and modern humans that occurred an estimated 100,000 years ago, which is tens of thousands of years earlier than other such events previously documented. They suggest that some modern humans left Africa early and mixed with Neanderthals. These modern humans later became extinct and are therefore not among the ancestors of present-day people outside Africa who left Africa about 65,000 years ago.
To find energy-rich food, like tropical ripe fruit, is a challenge for chimpanzees
In our supermarkets we buy raspberries in winter and chestnuts in summer. But how challenging would life become, if we needed to consume large amounts of fruit for our daily meal and had to collect them ourselves? With a largely plant-based diet, simple stomachs, and the additional cost of maintaining relatively large brains, chimpanzees face a serious challenge in their daily search for energy and nutrients. Using data on the monthly availability of young leaves, unripe and ripe fruits in three tropical rain forests in East, Central and West Africa, a consortium of researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, Harvard University, McGill University, the University of St. Andrews and the Université Félix Houphouët Boigny, estimated how difficult it is for chimpanzees to find food and to predict its availability in individual trees. This study reports which cognitive strategies chimpanzees can use to gain privileged access to the most energy-rich but ephemeral food.
Max Planck researchers found that our closest relatives, too, trust their friends
It almost goes without saying that trust is a defining element of genuine human friendship. Now, researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, suggest that the same holds true among chimpanzee pals. Their findings suggest that friendship based on trust has evolved much earlier than previously thought and is not unique to humans.
The mixing of archaic human forms played an important role in shaping the immune system of modern humans
When modern humans met Neanderthals in Europe and the two species began interbreeding many thousands of years ago, the exchange left humans with gene variations that have increased the ability of those who carry them to ward off infection. This inheritance from Neanderthals may have also left some people more prone to allergies. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and the Institut Pasteur and the CNRS in Paris, France, report about the discoveries in two independent studies, adding to evidence for an important role for interspecies relations in human evolution and specifically in the evolution of the innate immune system, which serves as the body's first line of defense against infection.