17 novembre 2015

La disparition de l'homme de Néandertal

Une nouvelle étude révèle que l'homme moderne ne serait pas responsable de l'extinction des Néandertaliens:

Neanderthals went extinct in Europe about 40,000 years ago, giving them millennia to coexist with modern humans culturally and sexually, new findings suggest.

This research also suggests that modern humans did not cause Neanderthals to rapidly go extinct, as some researchers have previously suggested, scientists added.

(...) To help solve the mystery of when Neanderthals went extinct, scientists analyzed bone, charcoal and shell materials from 40 archaeological sites from Russia to Spain. They employed advanced techniques for more precise dating of these specimens that involved ultra-filtering molecules from bone samples for examination and removing organic contaminants that could make specimens seem younger than they actually are.

The new findings suggest that Neanderthals disappeared from Europe between about 41,000 and 39,000 years ago.

"I think that, for the first time, we have a reliable extinction date for Neanderthals," said study author Tom Higham, a radiocarbon scientist at the University of Oxford in England. "This has eluded us for decades."

The Neanderthal extinction occurred across sites ranging from the Black Sea to the Atlantic Coast of Europe. The timing and geography suggest Neanderthals may have overlapped with modern humans for 2,600 to 5,400 years, opening the door for genetic and cultural exchanges between the two groups for millennia.

These findings suggest that modern humans did not rapidly replace Neanderthals in Europe — say, via violent means. Rather, the Neanderthal extinction "might have been more complex and drawn out than previously thought," Higham told Live Science.

There is some genetic evidence that Neanderthals in Western Europe may have experienced declining genetic diversity about the time when the first modern humans began arriving on the continent, Higham said. "This might mean that they were fading out at this time, although, of course, our evidence suggests that there was a long period of overlap during which this occurred," he said.

Neanderthals may not even have truly disappeared, but instead have been assimilated into modern human populations. "We know, of course, that we have a genetic legacy from Neanderthals of about 1 to 2 percent, so there was interbreeding," Higham said.



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