If you're African then you're not a Neanderthal...

[RIPP_n_WIPE]

...o and if you're aboriginal Australian.

The next time you're tempted to call some oaf a Neanderthal, you might want to take a look in the mirror.

According to a new DNA study, most humans have a little Neanderthal in them—at least 1 to 4 percent of a person's genetic makeup.

The study uncovered the first solid genetic evidence that "modern" humans—or Homo sapiens—interbred with their Neanderthal neighbors, who mysteriously died out about 30,000 years ago.

What's more, the Neanderthal-modern human mating apparently took place in the Middle East, shortly after modern humans had left Africa, not in Europe—as has long been suspected.

"We can now say that, in all probability, there was gene flow from Neanderthals to modern humans," lead study author Ed Green of the University of California, Santa Cruz, said in a prepared statement.

That's no surprise to anthropologist Erik Trinkhaus, whose skeleton-based claims of Neanderthal-modern human interbreeding—previously contradicted with DNA evidence—appear to have been vindicated by the new gene study, to be published tomorrow in the journal Science.

"They've finally seen the light ... because it's been obvious to many us that this happened," said Trinkaus, of Washington University in St. Louis, Missouri, who wasn't part of the new study.

Trinkhaus adds that most living humans probably have much more Neanderthal DNA than the new study suggests.

"One to 4 percent is truly a minimum," Trinkaus added. "But is it 10 percent? Twenty percent? I have no idea."

(Also see "Neanderthals, Modern Humans Interbred, Bone Study Suggests.")

Surprising Spot for Neanderthal-Human Mating

The genetic study team reached their conclusion after comparing the genomes of five living humans—from China, France, Papua New Guinea, southern Africa, and western Africa—against the available "rough draft" of the Neanderthal genome. (Get the basics on genetics.)

The results showed that Neanderthal DNA is 99.7 percent identical to modern human DNA, versus, for example, 98.8 percent for modern humans and chimps, according to the study. (Related: "Neanderthals Had Same 'Language Gene' as Modern Humans.")

In addition, all modern ethnic groups, other than Africans, carry traces of Neanderthal DNA in their genomes, the study says—which at first puzzled the scientists. Though no fossil evidence has been found for Neanderthals and modern humans coexisting in Africa, Neanderthals, like modern humans, are thought to have arisen on the continent.

"If you told an archaeologist that you'd found evidence of gene exchange between Neanderthals and modern humans and asked them to guess which [living] population it was found in, most would say Europeans, because there's well documented archaeological evidence that they lived side by side for several thousand years," said study team member David Reich.

For another thing, Neanderthals never lived in China or Papua New Guinea, in the Pacific region of Melanesia, according to the archaeological record. (See "Neanderthals Ranged Much Farther East Than Thought.")

"But the fact is that Chinese and Melanesians are as closely related to Neanderthals" as Europeans, said Reich, a population geneticist at the Broad Institute of MIT and Harvard University.

(See pictures of a reconstructed Neanderthal and take a Neanderthals quiz.)

Neanderthal-Human One-Night Stand?

So how did modern humans with Neanderthal DNA end up in Asia and Melanesia?

Neanderthals, the study team says, probably mixed with early Homo sapiens just after they'd left Africa but before Homo sapiens split into different ethnic groups and scattered around the globe.

The first opportunity for interbreeding probably occurred about 60,000 years ago in Middle Eastern regions adjacent to Africa, where archaeological evidence shows the two species overlapped for a time, the team says.

And it wouldn't have taken much mating to make an impact, according to study co-author Reich. The results could stem from a Neanderthal-modern human one-night stand or from thousands of interspecies assignations, he said.

(Related: "Neanderthals Grew Fast, but Sexual Maturity Came Late.")

More DNA Evidence for Neanderthal-Human Mating

The new study isn't alone in finding genetic hints of Homo sapiens-Homo neanderthalensis interbreeding.

Genetic anthropologist Jeffrey Long, who calls the Science study "very exciting," co-authored a new, not yet published study that found DNA evidence of interbreeding between early modern humans and an "archaic human" species, though it's not clear which. He presented his team's findings at a meeting of the American Association of Physical Anthropologists in Albuquerque, New Mexico, last month.

Long's team reached its conclusions after searching the genomes of hundreds of modern humans for "signatures of different evolutionary processes in DNA variation."

Like the new Science paper, Long's study speculates that interbreeding occurred just after our species had left Africa, but Long's study didn't include analysis of the Neanderthal genome.

"At the time we started the project, I never imagined I'd ever see an empirical confirmation of it," said Long, referring to the Science team's Neanderthal-DNA evidence, "so I'm pretty happy to see it."

http://news.nationalgeographic.com/news ... -dna-gene/

Posted without comment.

EDIT: Added a link.

[Pelranius]

Well, assuming that you're not an African or Australian Aborigine with some Asian or Caucasian ancestry (as I understand it, the latter is very common and the former is very common too, at least in the Western Hemisphere).

[Broomstick]

Hmmm... Is it possible that early modern human and neanderthals 60,000 years ago were still close enough to produce offspring, but by 30,000 years ago, the period of H. sapiens and H. neanderthal co-existence in Europe they were just far enough apart to no longer produce offspring? Or is that too narrow a time frame?

I'm just tentatively putting that forward as a possible explanation why Europeans appear no more closely related than Asians to H. neanderthal. Very much subject to change with new evidence and/or better explanation from a someone formally trained in this sort of thing.

[Alkaloid]

I'm just tentatively putting that forward as a possible explanation why Europeans appear no more closely related than Asians to H. neanderthal. Very much subject to change with new evidence and/or better explanation from a someone formally trained in this sort of thing.

There were other species of H. whatever living in Asia as well though, and the article indicates that there is evidence of early humans breeding with other species other than the Neanderthals, so it's also possible that the people moving into Europe kept breeding with Neanderthals, while those moving into Asia found new and exciting people to have sex with, and a s long as people kept migrating out of Africa (as I understand they did) bringing a constant new influx of Homo Sapiens genes without a new source of Neanderthal or whoever else genes, you may get a similar result without more than superficial differences in people from Europe and Asia.

[Melchior]

Hmmm... Is it possible that early modern human and neanderthals 60,000 years ago were still close enough to produce offspring, but by 30,000 years ago, the period of H. sapiens and H. neanderthal co-existence in Europe they were just far enough apart to no longer produce offspring? Or is that too narrow a time frame?

It's too narrow, but there are studies suggesting that the interbreeding potential, while existent and at this point supported by genetic evidence, was already marginal, meaning that most of the time the offspring died before birth or was not fertile. It's possible that the genetic material that our species got from neanderthals came from a very limited number of individuals.

[The Duchess of Zeon]

First, Australian aboriginals aren't mentioned anywhere here, and other studies have shown they have Neanderthal DNA too. Secondly, East Asians and Melanesians actually also have Denisovan interbreeding remnants genetically, Denisovans being most likely a derivative of Homo heidelbergensis. They were very close to Neanderthals anyway.

[Alkaloid]

First, Australian aboriginals aren't mentioned anywhere here, and other studies have shown they have Neanderthal DNA too. Secondly, East Asians and Melanesians actually also have Denisovan interbreeding remnants genetically, Denisovans being most likely a derivative of Homo heidelbergensis. They were very close to Neanderthals anyway.

I understood there were some pretty confusing questions related to the Australian aboriginals genetics, and that about the most concrete anyone could say was that they definitely had African ancestors, and were not a case of convergent evolution and that was about it. Where did you find that information? (I'm not saying you're wrong, I'm just curious)

[RIPP_n_WIPE]

Yeah it was a separate article from Discover I linked at the top. You are correct though, the wording is just very weird.\\\

[The Duchess of Zeon]

This article references the study on Denisovans.

And this one is on the aboriginal ancestry containing both Denisovan and Neanderthal DNA. Note also that the level of Denisovan interbreeding with mainland East Asian populations is still under debate; some mainland east Asian populations may in fact have a relatively high admixture of both.

Anyway this is interesting because it may suggest the reason why some drugs seem to work on people in the rest of the world but not on many Africans. Though the vast, vast majority of genes are the same, Neanderthals, who had a more heavily fatty meat diet in arctic climes, may have given white and asian populations our greater resistance to heart disease, for instance. Any such results are still highly speculative, however.

[Akhlut]

Anyway this is interesting because it may suggest the reason why some drugs seem to work on people in the rest of the world but not on many Africans. Though the vast, vast majority of genes are the same, Neanderthals, who had a more heavily fatty meat diet in arctic climes, may have given white and asian populations our greater resistance to heart disease, for instance. Any such results are still highly speculative, however.

I'd be especially curious since most people of African descent in the Western hemisphere also have significant admixture with Europeans, making me wonder how significant Neanderthal genes would be in general from that point of view.