“The modern European gene pool was formed when three ancient populations mixed within the last 7,000 years, Nature journal reports.

“Blue-eyed, swarthy hunters mingled with brown-eyed, pale skinned farmers as the latter swept into Europe from the Near East.

“But another, mysterious population with Siberian affinities also contributed to the genetic landscape of the continent…

“This additional ‘tribe’ is the most enigmatic and, surprisingly, is related to Native Americans…

“Pigmentation genes carried by the hunters and farmers showed that, while the dark hair, brown eyes and pale skin of the early farmer would look familiar to us, the hunter-gatherers would stand out if we saw them on a street today.

“It really does look like the indigenous West European hunter gatherers had this striking combination of dark skin and blue eyes that doesn’t exist any more,’ Prof Reich told BBC News…

“‘Hunters and gatherers get vitamin D through their food – because animals have a lot of it. But once you’re farming, you don’t get a lot of it, and once you switch to agriculture, there’s strong natural selection to lighten your skin so that when it’s hit by sunlight you can synthesise vitamin D.'” (BBC Science, September 2014)