Neanderthal DNA Reveals Its Links to Sapiens

The case of kinship relations and the possible meeting between the two closest humanities – Homo sapiens, modern man has been in existence just over a hundred thousand years in Africa, and Neanderthal – is revealed this morning in the journal Science. For exceptionally long article, reflecting a meticulous work and precision. It is a real “turning point in the exploration of the origins of humanity by means of molecular genetics,” Peter welcomes Darlu, a geneticist who participated in 2006 to study the DNA of mitochondria, therefore, only maternal of Neanderthals.

Science Headlines Who are the narrators of this story, authors of the “tremendous work” says Pierre Darlu? An international team of high-flying, led by Svante Pääbo, a Swedish biologist. Svante Pääbo, multidiplômé in literature, Egyptology, history and biology was one of the pioneers in the exploration of ancient DNA. In 1985, he was interested in the genes of Egyptian mummies. In 1991, he headlined “the dream become reality?” About DNA from 16 million years. He leads from the Max Planck Institute in Leipzig, a team of nearly 60 researchers from many countries (Germany, USA, Spain, Croatia, Ireland, United Kingdom, Russia), launched an assault on the genome Neanderthal. It has sequenced the Neanderthal bone DNA from fossil bones of Neanderthals found in the Vindija Cave, Croatia. And managed to gather 60% of their total genomes. The veil is now lifted the Neanderthal genetic identity, and as a result of what sets us apart and it is our own genetic identity.

It’s a real technical feat that the team assembled by Svante Pääbo has achieved. Their equipment? Tiny particles of bone, spare wheel to the dentist three bones (photo right) selected from 21 candidates. One dated from 38,000 years and discovered in 1980. A second older but undated and the third oldest dated to 44,000 years. Bones slightly contaminated with DNA from modern humans. As the three were Neanderthals … the ladies, the trick was to measure the contamination in male DNA, the Y chromosome, not more than 1.5%.

Comparing genomes extremely close to each other required to use techniques and sophisticated statistical tests. In addition to sequencing the fossil bones of the cave Vindjia, the team relied on so few strokes of the Map gene probes for other Neanderthal fossils, collected in three sites: El Sidron (Spain, 49,000 years) the Neander Valley (Germany, 40 000 years) and Mezmaiskaya (Caucasus, Russia, -60 000 to -70 000 years). On the sequencing of five people present made for the occasion. And that of the famous Craig Venter, an American geneticist.

Geneticists have obtained a surprising result, which sheds new light on our kinship with this cousin disappeared. They contradict previous studies conducted on mitochondrial DNA exclusively breast, which had found no contribution to our Neanderthal genome, as conducted by Catherine Hänni (ENS Lyon) in 2006 by Pääbo. Pretending to reason and to those of homo sapiens prehistorians convinced, after leaving Africa in the Middle East, had never flirts with the Neanderthals who occupied so much of the ancient world, from Spain to Siberia.

A conviction based on the clear anatomical differences between the humanities. The skeleton of Cro-Magnon Neanderthal skull sapiens, long, slender, with a high forehead and smooth is clearly distinguishable from a Neanderthal stocky, with strong muscular attachments, and especially his head down, lying, boasting also a big brain size, and eyebrow spectacular. Rare anatomical evidence of interbreeding had been advanced, such as the American Erik Trinkaus, about fossils Mladec (Czech Republic or Lagar Velho in Portugal). But they had not won the conviction of most specialists.

However, according to Svante Pääbo’s team, there have been a blend. It reads more into the genome of modern humans as long as one can compare to that of Neanderthal. It is difficult to demonstrate, since the contribution to our Neanderthal genome is very discreet, yet undeniable.

This implies gene flow between the two populations after the divergence from our common ancestor Neanderthal – erectus – that occurred there are about 400 000 years. And before the disappearance of Neanderthals, the last representatives live in Western Europe, 30,000 years ago. When and where gene flow small but undeniable – the two species were not completely separated in reproductively, although this is the definition of species – did it happen?

Figure genetic response comes from the five men present, purposively selected for comparison. A French European style, a Han Chinese, a Papuan New Guinea, a Yoruba (West Africa) and San (South Africa). But the little game similarities, it is the Eurasian – French, Chinese and Papuan – which carry the palm of proximity Neanderthals almost equally between them.

How is this done? One solution, also suggested by archeology: the two species cousins ​​have “known” in the biblical sense … in the Middle East, there are about 80 000. Not after, for example in Europe 35,000 years ago, which would have resulted from a Neanderthal higher among Europeans than among the Papuan as Sapiens arrived in East Asia 60,000 years ago.

That would be when it came out of Africa, Homo sapiens would have met along the way of Neanderthal populations, then spread throughout the ancient world. “In the end, the region where the traces of cohabitation are clearer,” said Pascal Depaepe (2), archaeologist Neanderthal, scientific director of the National Institute of Preventive Archaeological Research. Archaeological sites in the Middle East show that the two species have shared this space for more than 30 000 years. At the time, moreover, “they had the same lithic technology, the Mousterian, and there was nothing to distinguish it from a cultural point of view while their anatomical differences are obvious,” said Depaepe.

What the researchers genetic proximity between a European and a Papuan with a Neanderthal is the same implies that there was no exchange of genes on the arrival of Cro-Magnon in Europe, where he lived with Neanderthal for nearly 10,000 years. A surprise? “After all, we have never seen convincing signs of interbreeding anatomical fossils found in Europe,” says Depaepe. Exit, then, the romantic speculation on the rape of Neanderthals by Cro-Magnon.

Caution, geneticists suggest an alternative track. A possible gene flow, low, between Cro-Magnons and Neanderthals in Europe may be masked by the stream of Neolithic farmers who overwhelmed the local population in Western Europe in its progression from Asia Minor, there are between 7000 and 4000 years.

This study also shows that most of the genetic differences between Neanderthals and modern humans are in genes related to cognitive abilities, energy metabolism and morphology of the skull. The distinctions between these two humanities seem to lie so well favored in the mind …. There is enough food for thought anthropologists and prehistory of Neanderthal, culture, the mystery of his disappearance and the relationships he had with Cro-Magnon … as on the mechanisms of cultural evolution of the latter.

This study estimates the pre-historian, will “exceed two extremist visions of old Neanderthal Neanderthal drawing that succeeded. Neanderthal was seen as being a bestial, ape-like, due to erroneous reconstructions of Marcelin Boule. Then, in recent years he has been rehabilitated to the point of making another man. Different, certainly, but not less. ” He was also a great hunter of large mammals – deer, rhinoceros, mammoths – which requires skill, anticipation and collective organization (3).

But other signs argue against it. His character almost exclusively carnivorous, the total absence of technology-based bone – while Cro-Magnon makes great use as spears and harpoons unknown Neanderthals – suggests different cognitive abilities. Lower? Pascal Depaepe remains cautious, and highlights the contradictions of most hypotheses to explain her disappearance. Climate? Of course, that time is “troubled” but Neanderthals had worse. Competition with Cro Magnon? He sees a trail more interesting. While the populations are very small, abundant game, but “a hunter needs wide open spaces.”

Chauvet This competition has clearly not played on equal terms. The Châtelperronian, name of the craft of stone that rises in Europe just before the disappearance of Neanderthals, has been interpreted as a sign of cultural influence on Neanderthal Cro Magnon, as some artistic productions, teeth or shells pierced it. But, says Depaepe, evidence that this industry is the fact Neanderthal “remains tenuous,” as it is based on only a single index, in St. Cesaire (Charente Maritime).

Above all, Sapiens plays upper division side brain and social development. Starting from 40 000 years ago, the evolution of lithic technology accelerates, artistic expression explodes (photo: the Chauvet), unmistakable sign of “more complex social relationships,” insists Depaepe. This will lead to the Neolithic revolution in the Middle East, Asia, Africa and America. Geneticists have it pinpointed what Neanderthals would have prevented to participate in the adventure? It’s possible.