The key evidence, presented in the journal Nature, is a newly discovered fossilized skull of a Homo sapiens who co-existed with Neanderthals and likely was a human-Neanderthal "love child." To this day, people of European and Asian heritage retain Neanderthal DNA as a result of the ancient encounters.
The partial skull, thought to have been part of a female human, has been named "Manot," after the cave in northern Israel where it was found. A high tech dating method determined that the skull is 55,000 years old.
"Manot clearly shows that Neanderthals and modern human lived side by side in Israel for a long period of time," co-author Israel Hershkovitz of Tel Aviv University told Discovery News. "All recent genetic and archaeological studies predict that the interbreeding event between the Neanderthals and modern humans occurred between 50,000-60,000 years ago, and in the Near East."
Hershkovitz and other Israeli scientists, as well as anthropologists from the University of Vienna and the Max Planck Institute, Leipzig, used a barrage of high tech methods, including computer tomography, to study Manot in detail. They then compared this information with data on hundreds of other early human skulls to note differences and similarities.
"The shape analysis shows very clearly that Manot was a modern human," co-author Gerhard Weber of the University of Vienna said. "It is interesting that the most similar skulls in our sample come from recent Africans on the one hand, and on the other hand from those modern humans that lived in Europe between 20,000-30,000 years ago."
Manot is clearly much older than those Europeans, however, and even pre-dates the first known Homo sapiens in Europe by 10,000 years. This weakens theories that our species and Neanderthals first encountered each other in Europe.
Given the timing as well as Manot's mixture of features, Weber suspects "it could be that Manot is one of the hybrids," meaning part Homo sapiens and part Neanderthal. Other archaic human species lived in Europe and Asia then as well, so additional interbreeding might have taken place between these groups.
Manot is also important because it sheds light on a central migration route taken by our species out of Africa.
At first it was thought that our direct ancestors traveled from Africa via a southern coastal route across the Red Sea to the Arabian Peninsula. Now the researchers suspect that Manot and her Homo sapiens predecessors traveled north from East Africa to the Nubian Desert before continuing on to the Sinai Peninsula and then to Israel.
Weber believes that there were several prehistoric migrations of humans out of Africa and into Europe and Asia beginning well over 100,000 years ago. However, the "successful wave" -- the group that replaced/absorbed all of the others upon arrival -- happened closer to Manot's time.
Chris Stringer of the Natural History Museum supports the theory that Manot could represent the earliest known meeting and mating between our species and Neanderthals.
Stringer told Discovery News that "it is the first modern human from western Asia that is well dated to the estimated time frame of interbreeding between early modern humans and Neanderthals."
He added, "Manot might represent some of the elusive first migrants in the hypothesized out-of-Africa event about 60,000 years ago, a population whose descendants ultimately spread right across Asia and also into Europe."
Read more at Discovery News
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