First Neanderthal man with Homo sapiens genes

Genetic analyzes suggest mixing both species around 100, 000 years ago

The first modern humans could have left Africa around 100, 000 years ago and mixed with Neanderthals. © Ivan Heredia / CSIC
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Early encounter: Neanderthal man and modern man already fathered children with each other ten thousands years earlier than previously thought. The finding of Homo sapiens genes in a Neanderthal from the Altai Mountains suggests this. The exciting thing is that the source of these genes must have been a group of modern humans who left Africa long before the ancestors of Europeans, as researchers report in the journal "Nature".

Although the Neanderthal is not a direct ancestor of modern humans, but he still has left genetic traces: We carry around two percent Neanderthal DNA in our Europeans, because some of our ancestors mated with Neanderthals and children begat. "This mixing took place just over 65, 000 years ago, when modern human populations spread from Africa across Europe and Asia, " says senior author Sergi Castellano of the Max Planck Institute for Evolutionary Anthropology in Leipzig.

Mixing with opposite sign

Now, however, researchers have found evidence of another, even earlier, mixture of the two human species when analyzing the genome of a Neanderthal man from the Altai Mountains. The DNA of this Neanderthal man had gene variants, as they also occur in modern Africans. However, their ancestors never came out of Africa and therefore can not inherit these genes from Neanderthals.

Instead, these genes must have once come from Africa to the Altai Neanderthals. "The exciting thing about this find is that it suggests mixing in the opposite direction, " explains Adam Siepel of the Cold Spring Harbor Laboratory. "Here we have DNA of Homo sapiens in the Neanderthal genome instead of the well-known Neanderthal DNA in the genome of modern humans." This means that the half-breed children stayed with the Neanderthals and passed on their genes there.

Scenario for mixing modern humans and Neanderthals: Neanderthal DNA in humans today living outside of Africa dates back to 47, 000-65, 000 years ago (green arrow). DNA of modern humans in Neanderthals is probably the result of an earlier contact between both groups about 100, 000 years ago (red arrow). Ilan Gronau

Only in the Altai, not in Europe

Interestingly, these gene variants derived from Homo sapiens were found only in the Neanderthal from the Altai region, not in his fellow species living in Europe. This was the result of DNA analyzes of a Neanderthal man found in Spain and one in Croatia. The Denisova man, who also lives in the Altai Mountains, does not seem to have had any part in this mixture with modern man, as the researchers report. display

"The signal we see in the Altai Neanderthals probably comes from a mingling event that only took place after this particular Neanderthal line began to develop separately from the line of its European cousins ​​just over 100, 000 years ago, " explains Siepel.

Contact long before the colonization of Europe

These findings, however, suggest that the Altai Neanderthals mingled with modern humans tens of thousands of years earlier than previously thought. Instead of meeting each other only about 60, 000 years ago in Europe, the two human species in the south of Siberia had apparently been in contact with each other some 100, 000 years ago.

This in turn means that at least one group of modern humans must have left Africa for Asia long before they moved to Europe. This fits in well with archaeological findings: in China, only 80, 000 years ago, teeth of a Homo sapiens were discovered and even earlier genetic studies speak in favor of a first, early emigration wave from Africa,

"The presence of modern humans and Neanderthals in the Levant some 120, 000 years ago could provide a place where Neanderthals and Homo sapiens mingled early on, " say the researchers. From there, the Neanderthals, together with the offspring of the mixed pairings, could have moved further into the Altai. (Nature, 2016; doi: 10.1038 / nature16544)

(Max Planck Society / Cold Spring Harbor Laboratory, 18.02.2016 - NPO)