Shared genes point to interbreeding with modern humans
THURSDAY, May 6 (HealthDay News) -- Researchers have sequenced the genome of the Neanderthal, Homo sapiens' closest evolutionary relative, in a feat that could ultimately shed light on what makes humans uniquely human.
As it turns out, 1 percent to 4 percent of the DNA in modern humans outside of Africa was probably inherited from Neanderthals, apparently because humans and Neanderthals at some point interbred.
There was no sign of Neanderthal DNA in modern-day individuals from Africa, suggesting that the interbreeding occurred after Neanderthals migrated out of that continent.
The studies also showed that, because of a shared lineage stretching far back in time, the DNA of modern humans is 99.7 percent identical to that of Neanderthals. In comparison, today's humans share about 98.8 of their genetics with their close primate relative the chimpanzee.
Previous tests -- albeit on only a fraction of the DNA analyzed in two new papers in the May 7 issue of Science -- had indicated that the two groups (scientists are unsure whether to actually call them separate species) had mated.
"It's extremely satisfying that we now have a first overview of the Neanderthal genome after four years of intense effort," said Svante Pääbo, senior author of the two papers. "This is exciting because Neanderthals are our closest evolutionary relative. If we want to define genetically what makes all humans that live today unique . . . we can begin to do so."
"In a way, 1-to-4 percent of the DNA that I carry in my cells, if I come from outside Africa, is from Neanderthals," added Pääbo, who is a geneticist with the Max-Planck Institute for Evolutionary Anthropology in Leipzig, Germany. "Neanderthals are not totally extinct. In some of us, they live on a little bit."
Pääbo spoke at a Wednesday news confer
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