Human evolution News

“Extinct” Denisovans’ genes found in Oceania peoples

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From ScienceDaily:

Archaic Denisovan and Neanderthal DNA that persists in modern Pacific islanders of Melanesia, far from the Siberian cave where Denisovan fossils have been found, is a source of information about early human history. Equally informative are genome regions where DNA from extinct, human-like species has vanished and been replaced with sequences unique to people. These large regions have genes for brain development, language and brain cell signalling. Retained archaic DNA in human genomes may confer infection-fighting advantages.

Denisovans are related to, but distinct from, Neanderthals. This prehistoric species was discovered less than a decade ago through genetic analysis of a finger bone unearthed in northern Siberia. Named for the mountain cave where that fossil, and later, two teeth, were found, Denisovans became a new addition to our ancient cousins on the evolutionary tree.

Substantial amounts of Denisovan DNA have been detected in the genomes of only few present-day human populations so far. They are all living in Oceania, thousands of miles away from that Siberian cave.

“I think that people (and Neanderthals and Denisovans) liked to wander,” said Benjamin Vernot, a UW postdoctoral student in genomic sciences who led the project. “And yes, studies like this can help us track where they wandered.”

“Denisovans are the only species of archaic humans about whom we know less from fossil evidence and more from where their genes show up in modern humans,” Akey said.

Denisovan DNA could make up between 2 percent to 4 percent of the genome of a native Melanesian. Lower levels of Denisovan ancestry, other recent studies suggest, may be more widespread in the world. More. Paper. (public access)

The way the article is written, the authors seem to want to advance the idea that all these groups were different “species” despite them not seeming to know it themselves.

No one seems in any hurry to address, let alone clear up, the confusion, which one keeps running into in news about speciation.

Also, if people’s genes continue to the present day, can they really be said to be “extinct”?  It sounds as if these terms were stuck on when we just didn’t know so much.

See also: BBC: Flores Man was not human; doesn’t have chin

The Little Lady of Flores spoke from the grave. But said what, exactly?

and

Neanderthal Man: The long-lost relative turns up again, this time with documents

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