Monday, January 27, 2014

7,000-Year-Old Human Bones Suggest New Date for Light-Skin Gene

An illustration of what the ancient hunter-gatherer may have looked like 

  
An ancient European hunter-gatherer man had dark skin and blue eyes, a new genetic analysis has revealed.

The analysis of the man, who lived in modern-day Spain only about 7,000 years ago, shows light-skin genes in Europeans evolved much more recently than previously thought.

The findings, which were detailed today (Jan. 26) in the journal Nature, also hint that light skin evolved not to adjust to the lower-light conditions in Europe compared with Africa, but instead to the new diet that emerged after the agricultural revolution, said study co-author Carles Lalueza-Fox, a paleogenomics researcher at Pompeu Fabra University in Spain. 
Sunlight changes

Many scientists have believed that lighter skin gradually arose in Europeans starting around 40,000 years ago, soon after people left tropical Africa for Europe's higher latitudes. The hunter-gatherer's dark skin pushes this date forward to only 7,000 years ago, suggesting that at least some humans lived considerably longer than thought in Europe before losing the dark pigmentation that evolved under Africa's sun.

"It was assumed that the lighter skin was something needed in high latitudes, to synthesize vitamin D in places where UV light is lower than in the tropics," Lalueza-Fox told LiveScience.

Scientists had assumed this was true because people need vitamin D for healthy bones, and can synthesize it in the skin with energy from the sun's UV rays, but darker skin, like that of the hunter-gatherer man, prevents UV-ray absorption.

But the new discovery shows that latitude alone didn't drive the evolution of Europeans' light skin. If it had, light skin would have become widespread in Europeans millennia earlier, Lalueza-Fox said.

Mysterious find

In 2006, hikers discovered two male skeletons buried in a labyrinthine cave known as La Braña-Arintero, in the Cantabrian Mountains of Spain. [Images of the Ancient Skeletons]

At first, officials thought the skeletons may have been recent murder victims. But then, an analysis revealed the skeletons were about 7,000 years old, and had no signs of trauma. The bodies were covered with red soil, characteristic of Paleolithic burial sites, Lalueza-Fox said.

For the rest of the story: http://www.livescience.com/42838-european-hunter-gatherer-genome-sequenced.html

No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...