Could Neanderthals Saved Mankind Out of Africa by Making Them Whiter?

Tags: Light Skin Neanderthals Mated with Humans Out of Africa, Gene Skin Pigmentation, Sun forms Vitamin D, Survival,

These conclusions are not considered in the article, but seems to correlate more closely with the genetic data than those proposed by the scientists.Note that I condensed the article greatly with what sections I thought were more important to the general public.

Beware, only one person was selected for a complete genome analysis from various ethnic regions sources, but it is probably good enough. Neanderthals had pale skin with red hair. Pale skin was needed to get the weak sun in the north to produce enough vitamin D to survive. The offspring of those who mated with Neanderthals survived and carried to skin color genes needed to survive. Neanderthals have been around for more than 200,000 years.

Africans do not have those Neanderthal genes of 1-4% found in Europeans and Asians. I am sure these data shocked the mostly white modern humans who did the study. Here is a related excerpt near the end of the very long article:

... But the mutations they've found so far "are all very interesting, precisely because there are so few," says Pääbo, whose team is trying to identify their function. The catalog includes changes in genes that encode proteins important for wound healing, the beating of sperm flagellum, and gene transcription (see table, above). Several of these newly evolved modern human genes encode proteins expressed in the skin, sweat glands, and innersheaths of hair roots, as well as skin pigmentation. "The fact that three of six genes carrying multiple substitutions are in skin is fascinating," says Poinar. Pääbo speculates that these changes "reflect that skin physiology has changed but how, of course, we don't know yet." ... http://www.sciencemag.org/cgi/content/full/328/5979/680

Jim Kawakami, May 6, 2010, http://jimboguy.blogspot.com

Could Neanderthals Saved Mankind Out of Africa by Making Them Whiter? "Close Encounters of of the Prehistoric Kind" by Ann Gibbons May 7, 2010 http://www.sciencemag.org/cgi/content/full/328/5979/680

... On page 710, an international team of researchers presents theirfirst detailed analysis of the draft sequence of the Neandertalgenome, which now includes more than 3 billion nucleotides collected from the bones of three female Neandertals who lived in Croatia more than 38,000 years ago. By comparing this composite Neandertal genome with the complete genomes of five living humans from different parts of the world, the researchers found that both Europeans and Asians share 1% to 4% of their nuclear DNA with Neandertals. But Africans do not. This suggests that early modern humans interbred with Neandertals after moderns left Africa, but before they spread into Asia and Europe. The evidence showing interbreeding is "incontrovertible," says paleoanthropologist John Hawks of the University of Wisconsin, Madison, who was not involved in the work. "There's no other way you can explain this."

As a result, many people living outside Africa have inherited a small but significant amount of DNA from these extinct humans. "In a sense, the Neandertals are then not altogether extinct," says lead author Svante Pääbo, a paleogeneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who was surprised to find he was part Neandertal. "They live on in some of us."

The team also used the Neandertal DNA like a probe to find the genes that make us modern. Even though the genomes of humans and Neandertals are 99.84% identical, the researchers identified regions that have changed or evolved since our ancestors and Neandertals diverged sometime between 270,000 and 440,000 years ago—their new, slightly younger estimate of the split. So far, the team has detected tantalizing differences in genesinvolved in metabolism, skin, the skeleton, and the development of cognition, although no one knows yet how these genetic changes affect physiology. "This is a groundbreaking study!" enthuses evolutionary geneticist Hendrik Poinar of McMaster University in Hamilton, Canada. "We can actually discuss an extinct human species—Neandertals—on a genetic level rather than strictly on morphological grounds."

Mixed marriage

The discovery of interbreeding in the nuclear genome surprised the team members. Neandertals did coexist with modern humans in Europe from 30,000 to 45,000 years ago, and perhaps in the Middle East as early as 80,000 years ago (see map, p. 681). But there was no sign of admixture in the complete Neandertal mitochondrial (mtDNA) genome or in earlier studies of other gene lineages (Science, 13 February 2009, p. 866). And manyresearchers had decided that there was no interbreeding that led to viable offspring. "We started with a very strong bias against mixture," says co-author David Reich of Harvard Medical School in Boston. Indeed, when Pääbo first learned that the Neandertal DNA tended to be more similar to European DNA than to African DNA, he thought, "Ah, it's probably just a statistical fluke." When the link persisted, he thought it was a bias in the data. So the researchers used different methods in different labs to confirm the result. "I feel confident now because three different ways of analyzing the data all come to this conclusion of admixture," says Pääbo.

The finding of interbreeding refutes the narrowest form of a long-standing model that predicts that all living humans can trace their ancestry back to a small African population that expanded and completely replaced archaic human species without any interbreeding. "It's not a pure Out-of-Africa replacement model—2% interbreeding is not trivial," says paleoanthropologist Chris Stringer of the Natural History Museum in London, one of the chief architects of a similar model. But it's not wholesale mixing, either: "This isn't like trading wives from cave to cave; the amount of admixture is tiny," says molecular anthropologist Todd Disotell of New York University in New York City. "It's replacement with leakage."

Although the 1.3-fold coverage of the Neandertal genome is aremarkable technical feat, one-third of the genome is still murky. In a separate paper (p. 723), the team describes and successfully tests a new method for filling in gaps in the rough draft of the genome.

The team also used three methods to nail down the interbreedingresult. First, they compiled the Neandertal genome using DNA from the limb bones of three female Neandertals who lived in Vindija Cave in Croatia from 38,000 to 44,000 years ago; they confirmed parts of the genome with much smaller amounts of DNA from Neandertals who lived in Spain, Germany, and Russia.

Once they were satisfied that the composite genome was a fair representation of Neandertals from across a great part of their geographical range, researchers compared the Neandertal genome to a chimpanzee's to determine which genetic variants were primitive, ancestral forms. Then they compared the new, derived genetic variants in Neandertals to those in the complete genomes of five living humans, including a San from Southern Africa, aYoruba from West Africa, a Papua New Guinean, one Han Chinese, and one French European.

The team measured the genetic proximity of Neandertals to pairs of modern humans from different continents, first using single-nucleotide polymorphisms (SNPs), or sites in the genome where a single nucleotide differs between individuals. When they compared a Neandertal with a European and an Asian, they found that theNeandertal always shared the same amount of derived (or more recently evolved) SNPs with each of them. But when they compared a Neandertal with an African and a European, or with an African and an Asian, the Neandertal always shared more SNPs with the European or Asian than with the African. "We've shown that Neandertals are significantly more closely related to non-Africans than Africans on average," says Reich. ...

Some of those changes are likely to be neutral changes that accumulated through genetic drift, but the team also used the Neandertal data to find other evolutionary changes that were beneficial to modern humans and so rose to high frequencies in some populations. Specifically, they have identified 15 regions containing between one and 12 genes. The widest region is located on chromosome 2 and contains the gene THADA, a region that varies in modern humans and that has been associated with type 2 diabetes. Changes in this gene may have affected energy metabolism in modern humans.

But the mutations they've found so far "are all very interesting, precisely because there are so few," says Pääbo, whose team is trying to identify their function. The catalog includes changes in genes that encode proteins important for wound healing, the beating of sperm flagellum, and gene transcription (see table, above). Several of these newly evolved modern human genes encode proteins expressed in the skin, sweat glands, and innersheaths of hair roots, as well as skin pigmentation. "The fact that three of six genes carrying multiple substitutions are in skin is fascinating," says Poinar. Pääbo speculates that these changes "reflect that skin physiology has changed but how, of course, we don't know yet." ... http://www.sciencemag.org/cgi/content/full/328/5979/680