Humans Are Not Descended
From Neanderthals


LONDON (Reuters) - Modern humans are not descended from Neanderthals but co-existed with them about 40,000 years ago, scientists said Tuesday.
An analysis of DNA extracted from the ribs of a 29,000 year-old Neanderthal infant buried in a cave in southern Russia showed it was too distinct to be related to humans.
"There wasn't much, if any mixture, between Neanderthals and modern humans," William Goodwin, of the University of Glasgow, told Reuters.
"Though they co-existed we can't find any evidence of genetic material being passed from Neanderthals to modern humans," he added.
The study, reported in the science journal Nature, also supports the "Out of Africa" theory of modern human evolution -- that modern humans evolved from a common ancestor in Africa and spread across the world around 100,000 years ago.
The bones from the Neanderthal infant were very well preserved and came from among the last of the Neanderthals who died out about 30,000 years ago.
Exactly what happened to them is a mystery. Various theories suggest they were either killed, lost out to competitors or simply absorbed by modern humans.
The research by Goodwin and his Swedish and Russian colleagues is also important because it verifies the findings of the first analysis of Neanderthal DNA in 1997.
That study of DNA taken from the first Neanderthal skeleton found in the Feldhofer Cave in Germany in 1856 supports the theory that modern humans replaced Neanderthals.
The DNA sequence from the infant was very similar to the specimen from the Feldhofer Cave -- proving both are genuinely Neanderthals and that there was little diversity among them, according to Goodwin.
"If they had been very diverse at the DNA level they could have encompassed modern humans. The fact that these two Neanderthals are closely related and not related to modern humans implies that they don't have the diversity to encompass a modern human gene pool," said Goodwin.
DNA comparisons also showed that different ethnic groups do not have any links to Neanderthals.
"We compared the amount of difference between the Neanderthal sequence and a group of European, African and Asians. There is no real difference.... That suggests they are not more closely related to either one of those races," said Goodwin.
In a commentary on the research in Nature, Matthias Hoss, of the Swiss Institute for Experimental Cancer Research, said the two studies provide the most reliable proof so far of the authenticity of ancient DNA sequences.
The similar features of the two samples "argues against the idea that modern Europeans are at least partly of Neanderthal origin," he said.


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