DNA test of 7,000-year-old tooth overturns popular image of light-skinned European hunter-gatherers [View all]

[ashling]

http://www.rawstory.com/rs/2014/01/26/dna-test-of-7000-year-old-tooth-overturns-popular-image-of-light-skinned-european-hunter-gatherers/

DNA taken from the wisdom tooth of a European hunter-gatherer has given scientists an unprecedented glimpse of modern humans before the rise of farming. The Mesolithic man, who lived in Spain around 7,000 years ago, had an unusual mix of blue eyes, black or brown hair, and dark skin, according to analyses of his genetic make-up.

He was probably lactose intolerant and had more difficulty digesting starchy foods than the farmers who transformed diets and lifestyles when they took up tools in the first agricultural revolution.

The invention of farming brought humans and animals into much closer contact, and humans likely evolved more robust immune systems to fend off infections that the animals passed on. But scientists may have over-estimated the impact farming had in shaping the human immune system, because tests on the hunter-gatherer’s DNA found that he already carried mutations that boost the immune system to tackle various nasty bugs. Some live on in modern Europeans today.

*****
The DNA threw up a series of surprises. When Lalueza-Fox looked at the genome, he found that rather than having light skin, the man had gene variants that tend to produce much darker skin. “This guy had to be darker than any modern European, but we don’t know how dark,” the scientist said.

Another surprise finding was that the man had blue eyes. That was unexpected, said Lalueza-Fox, because the mutation for blue eyes was thought to have arisen more recently than the mutations that cause lighter skin colour. The results suggest that blue eye colour came first in Europe, with the transition to lighter skin ongoing through Mesolithic times.