Monday, July 18, 2011

Independent Research Line Confirms "Neanderthal" Genes in Most Humans

Eventually they'll get it right...

From Discovery News
All Non-Africans Part Neanderthal, Genetics Confirm
Analysis by Jennifer Viegas
Mon Jul 18, 2011 10:25 AM ET

If your heritage is non-African, you are part Neanderthal, according to a new study in the July issue of Molecular Biology and Evolution. Discovery News has been reporting on human/Neanderthal interbreeding for some time now, so this latest research confirms earlier findings.

Damian Labuda of the University of Montreal's Department of Pediatrics and the CHU Sainte-Justine Research Center conducted the study with his colleagues. They determined some of the human X chromosome originates from Neanderthals, but only in people of non-African heritage.

"This confirms recent findings suggesting that the two populations interbred," Labuda was quoted as saying in a press release. His team believes most, if not all, of the interbreeding took place in the Middle East, while modern humans were migrating out of Africa and spreading to other regions.

The ancestors of Neanderthals left Africa about 400,000 to 800,000 years ago. They evolved over the millennia mostly in what are now France, Spain, Germany and Russia. They went extinct, or were simply absorbed into the modern human population, about 30,000 years ago.

Neanderthals possessed the gene for language and had sophisticated music, art and tool craftsmanship skills, so they must have not been all that unattractive to modern humans at the time.

"In addition, because our methods were totally independent of Neanderthal material, we can also conclude that previous results were not influenced by contaminating artifacts," Labuda said.

This work goes back to nearly a decade ago, when Labuda and his colleagues identified a piece of DNA, called a haplotype, in the human X chromosome that seemed different. They questioned its origins.

Fast forward to 2010, when the Neanderthal genome was sequenced. The researchers could then compare the haplotype to the Neanderthal genome as well as to the DNA of existing humans. The scientists found that the sequence was present in people across all continents, except for sub-Saharan Africa, and including Australia.

"There is little doubt that this haplotype is present because of mating with our ancestors and Neanderthals," said Nick Patterson of the Broad Institute of MIT and Harvard University. Patterson did not participate in the latest research. He added, "This is a very nice result, and further analysis may help determine more details."

David Reich, a Harvard Medical School geneticist, added, "Dr. Labuda and his colleagues were the first to identify a genetic variation in non-Africans that was likely to have come from an archaic population. This was done entirely without the Neanderthal genome sequence, but in light of the Neanderthal sequence, it is now clear that they were absolutely right!"

The modern human/Neanderthal combo likely benefitted our species, enabling it to survive in harsh, cold regions that Neanderthals previously had adapted to.

"Variability is very important for long-term survival of a species," Labuda concluded. "Every addition to the genome can be enriching."

The article is confusing, to say the least, because according to current theory, ALL people came out of Africa, including the ancestors of so-called Neanderthal.  So, when the article says "non-African" heritage, to what population is that pointing to?  Only people with no "black" African ancestry?  But I thought we ALL were descended from black Africans.  Didn't we all start out black skinned and over time different populations' skin color changed according to the level of sun received?  But if that's the case, why are people who live in the Nordic regions blond haired, white skinned and blue-eyed while the Native Americans and First Nations people who live in the Arctic regions are dark skinned and dark-eyed with black hair? 

There's a big part of the story still missing here, obviously, and in more ways than one!  For instance, if most of the interbreeding (which we know happened) between 'modern' humans and 'archaic' Neanderthals took place in the Middle East, how could this have had any impact on the resulting offspring and their offspring, etc. being able to adapt better to survival in cold Europe?  Where, in the Middle East, did it ever get that cold?  And does the Middle East include Egypt?

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