Some Neanderthals were red-heads

[Raven]

Some Neanderthals were red-heads
Ancient DNA contains clues about complexion.

Heidi Ledford


Pale complexions may have evolved many times over.Digital VisionAn analysis of 50,000-year-old Neanderthal DNA suggests that at least some of the ancient hominids probably had pale skin and red hair.

The findings, published this week in Science 1, are based on the sequence of a single gene, called mc1r . Humans with a less functional form of the MC1R protein are more likely to be fair skinned — an adaptation that may have helped inhabitants of high latitudes synthesize vitamin D more efficiently in limited sunlight.

Analyses of Neanderthal DNA are always subject to the problem of fossil samples being contaminated with modern human DNA in the lab or the field. But Carles Lalueza-Fox of the University of Barcelona, Spain, with Holger Römpler of the University of Leipzig in Germany and colleagues, found that the mc1r gene in two European Neanderthal fossils they studied contained a single base-pair change that seems to be unique to Neanderthals.

“We were lucky we found a variant that had not been described in modern humans,” says co-author Michael Hofreiter of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “That made it unlikely to be human contamination.”

The researchers re-sequenced the applicable region of the gene multiple times, then asked two additional labs to repeat the experiments using fresh extracts. They also sequenced fragments of the mc1r gene from the researchers in each lab, as well as the archaeologists and palaeontologists who had handled the fossils. And they searched databases containing mc1r sequence from 2,800 humans and tested several hundred additional samples.

In the end, they had surveyed more than 3,700 humans, and none contained the Neanderthal sequence. “If it is in the modern human population, it’s at an extremely low frequency,” says Hofreiter.

Fair test
The researchers inserted the Neanderthal mc1r gene into human cells grown in the lab, and found that it had roughly the same low functionality as seen in mc1r genes from fair-skinned people with red hair.

It’s impossible to determine the precise frequency of pallid, red-haired Neanderthals that once populated Europe. But the researchers estimate that at least 1% of the population would have carried two copies of this less-active gene, giving them roughly the same pigmentation seen in modern red-heads.

Scientists have estimated that there should be at least a million nucleotides (single letters in the genome) that differ between humans and Neanderthals, says Lalueza-Fox. But little research has been done as yet to identify these. Recent work shows that Neanderthals have the same version of a speech gene as modern humans (see Modern speech gene found in Neanderthals). “This is the first functional difference in the genome between Neanderthals and modern humans,” says Lalueza-Fox.

Independent evolution
Lalueza-Fox and Hofreiter note that the absence of the Neanderthal-specific mc1r sequence in modern humans suggests that pale skin evolved independently in Neanderthals and humans, rather than from interbreeding between the two.


That's interesting but not entirely unexpected, says Rachel Caspari, an anthropologist at Central Michigan University in Mount Pleasant. The regulation of skin colour in humans is very complex, she notes; so she would expect evolution to have come up with many different ways to generate lighter skin.

Caspari cautions against ruling out genetic exchange between the two populations just yet. It is still possible that the allele was present in humans 50,000 years ago, but was later replaced by a different mutation, she says. “It certainly doesn’t support gene flow between Neanderthals and humans,” says Caspari, “but it doesn’t refute the idea either.”

http://www.nature.com/news/2007/071025/full/news.2007.197.html

[Prometheus]

Some Neandertals Were Pale Redheads, DNA Suggests   
Brian Handywerk
for National Geographic News

October 25, 2007
Some Neandertals may have had red hair and pale skin, just as some modern humans do, according to a new genetic study.

The traits were likely more common in European Neandertals (often spelled Neanderthals), just as they are often seen in modern humans of European descent.

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"I am quite sure this variant arose like the red hair variants in modern Europeans," said the study's lead author Carles Lalueza-Fox, of the University of Barcelona.

In the cases of both Neandertals and modern Europeans, he said, the gene mutation that caused fairer complexions spread only after the respective populations migrated from Africa.

Gene Keys Complexion Change

While studying Neandertal DNA samples, Lalueza-Fox's team found an unknown mutation in a key gene called MC1R.

Also present in modern humans, the gene regulates a protein that guides the production of melanin, which pigments hair and skin and protects from UV rays.

Variations in this gene's sequence limit melanin production in people with pale skin and red hair, although the particular mutation found by the researchers is not known to occur in modern humans.

The team tested the gene in living cells to see what effect the previously unknown variant would have had on the Neandertals who carried it. The test tube experiment showed that the variant suppressed the production of melanin, and thus likely gave the Neandertals who carried it red hair and pale skin.

Although it is not easy to find intact DNA from 230,000 to 30,000 years ago, Lalueza-Fox and his colleagues were able to study two separate samples unearthed in Italy and Spain.

The study was published today by the journal Science.

 http://news.nationalgeographic.com/news/2007/10/071025-Neandertals-Redheads.html

[Prometheus]

Close view of the skull of a Neandertal woman, dubbed Krapina 3 for the cave in the Balkans where her bones were unearthed. Some Neandertals may have had red hair and pale skin, according to research published Today.

Photograph by Kenneth Garrett/NGS

[Prometheus]

Lalueza-Fox believes the variant his team discovered was likely one of many that spread through ancient Neandertal populations by processes of natural selection.

"European [humans] have quite a lot of variation in this gene—not only red hair variants but also others," he explained, adding that humans have been in Europe for only about 40,000 years.

"The Neandertals, being there at least 400,000 [years], likely accumulated ten times more variation."

Neandertals are believed to have roamed Europe between 28,000 and 400,000 years ago.

James Noonan, a geneticist at the Yale University School of Medicine who was unaffiliated with the research, said Lalueza-Fox's conclusions were convincing.

"It's not surprising that there would be a Neandertal-specific MC1R variant that results in a partial loss of function (and thus lighter skin and hair)," he said. "Similar mutations have arisen independently in different modern human populations."

Another scientist who was not involved with the research, Henry Harpending, an anthropologist at the University of Utah in Salt Lake City, added that a number of genes that affect human skin color are still changing and spreading through Europe and Asia.

The particular genes that affects skin color are different in Europe and Asia, he said, but in both places, fairer complexions appear to be the result of broken versions of these genes.

"This paper suggests that Neandertals were light, or were getting light, in the same way, i.e., by selection for slightly broken genes," he said.

Scientists are not sure why the broken gene—and fairer complexions—would be spread by natural selection.

Yale's Noonan said geography was the likeliest explanation for the endurance of this trait in both modern humans and Neandertals—pigment advantage was likely less relevant in darker places.

Northern latitudes have "less sunlight and so less need for darker skin pigmentation to protect against UV-induced damage," Noonan said.

Though the genetic processes that helped to lighten their complexions may have worked similarly, humans have never displayed the same sequence seen in the ancient Neandertal gene samples.

"Both processes took place independently—that's the reason the Neandertal variant is not present in modern humans," Lalueza-Fox said.

The new find offers no evidence of interbreeding between humans and Neandertals, he added.

[rockessence]

The Bock saga tells us that the first pale skin, red/blonde hair, blue/green eyes, tall stature, came about because of the Aser/Vaner being trapped for the entire length of Ice-time within a warm pocket of the glacial ice of the far north.... It suggests that ice-time was more than 50 million years in length, and the final ice recession released the main pocket of them about 10,000 years ago. 

Other areas of habitation have been found around the White Sea and across the northern coasts of Siberia and probably also the north coast of Germany.   All of these were kept warm and ice free within the span of ice-time through the constant flow of the Gulf Stream which flowed through, crossing the land which is now part of Russian/Finnish Karelia and then into the White Sea and the Siberian coast.  This happened because the great weight of the glacial mass squashed the land down and made Scandinavia an island.... that is why it was called an island instead of a penninsula in the most ancient texts.  It is still rising today.



Note the area described above which was under water during ice-time.  As ice receded on the south side of the water, survivors would be released to migrate south.

[Adam Hawthorne]

I couldn't help connecting this with the Bock Saga as well, Rockessence.  Next revelation will be - Neanderthals are still among us!  In fact, they evolved into some of us.