A portion of Neanderthal DNA has been found in a high percentage of East Asians, according to a study published in the journal Molecular Biology and Evolution.

About 66 percent of all Southern Chinese contain genes that can be traced back to Neanderthals, according to the results of the study. This region of DNA includes some 18 genes from the Neanderthal genome including one gene, called HYAL2, which is related to UV light (sunlight) adaptation.

The DNA segment, or region of DNA, was found to be related to cells' reaction to sunlight and could play a role in how humans have adapted to sunlight. The study also confirms that the Neanderthal traits underwent positive selection, which is how advantageous traits becomes established in a population.

The findings come during a time of huge interest in comparative evolution being used to trace genetic ancestry. On Dec 18, the most complete sequence of Neanderthal DNA was published by a team of international researchers in the journal Nature. The study was completed with DNA extracted from a 50,000 year old toe bone that belonged to a Neanderthal woman.

Such a huge genetic library has the potential to define traits that set modern humans apart from their ancient ancestors, allowing for the most complete direct comparison between the two groups.

The genome shows that Neanderthals and humans lived side by side for a time and interbred. Senior author Qiliang Ding from Fudan University in Shanghai said: "We are trying to answer whether Neanderthals had a systematic contribution to modern humans that increased our adaptations to the local environment. "

What the researchers found through examination of the archaic human genomes reveal a clear infiltration of Neanderthal genes into the modern Eurasian gene pool. Not only that, but the study shows those Neanderthal traits underwent positive selection meaning the Neanderthal genes likely give some benefit to modern humans.

With the newly updated genetic database, researchers can compare and study portions of ancient DNA that has survived in modern humans. The hope of researchers is to show how much of an impact this has had on human development.

Though Ding and his team confirmed that this genetic region came from Neanderthals and is under positive selection, there is more work to be done. The authors would still like to experimentally study all the possibilities of the region.

"Other reports have found this region is related to keloid in Japanese and prostate cancer risk in Hispanics. We hope further investigation could be carried out to focus on the function of this region," he wrote.

elianakirshenblat@chinadailyusa.com

(China Daily USA 01/03/2014 page11)