It has generally been assumed that modern humans caused the demise of the Neanderthals, either by killing them directly or by simply out-competing them, claiming the best hunting territories, or surviving more effectively under Ice Age conditions. This new study suggests that none of those scenarios is correct.
The Swedish and Spanish scientists involved in the study, who were working on DNA from Neanderthal fossils found in Northern Spain, were surprised to discover that the genetic variation among European Neanderthals between 50,000 and 40,000 years ago was extremely limited.
?The amount of genetic variation in geologically older Neanderthals as well as in Asian Neanderthals was just as great as in modern humans as a species, whereas the variation among later European Neanderthals was not even as high as that of modern humans in Iceland?, one of the scientists explained.
On that basis, they concluded that most of the Neanderthals in Europe died out as early as 50,000 years ago. Just a small group survived and had managed to spread out through central and western Europe before modern humans showed up.
Last year, the redating of a Neanderthal fossil found in the northern Caucasus Mountains of Russia similarly suggested that Neanderthals in that area might have died out earlier than previously believed, perhaps before the arrival of modern humans.
It has also been established recently that that although all non-Africans carry a small amount of Neanderthal DNA, Asians have just as much of it as Europeans. This would seem to indicate that any interbreeding took place when modern humans first left Africa, and that the people who migrated from the Middle East tens of thousands of years later had little or no additional contact with Neanderthals once they reached Europe.
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