DNA: Europeans once dark with blue eyes

White skin arose later than thought



Genetic material recovered from a tooth of La Brana 1, an ancient man whose skeleton was dug up in a deep cave system in Spain in 2006, revealed a strange combination of dark skin and blue eyes, according to a study in the journal Nature.

Europeans from the Mesolithic Period between 10,000 and 5,000 years ago, when La Brana lived, were thought to have already been fair-skinned due to low ultraviolet radiation levels at those high latitudes.

“Until now, it was assumed that light skin color evolved quite early in Europe, (during) the Upper Paleolithic. . . . But this is clearly not the case,” said study co-author Carles Lalueza-Fox from Spain’s Evolutionary Biology Institute. “This individual had the African variants for the pigmentation genes.”

The Upper Paleolithic, or Late Stone Age, stretched from 50,000 to 10,000 years ago, followed by the Mesolithic, or Middle Stone Age, which lasted until about 5,000 years ago, when it was followed in Europe by the Neolithic, or New Stone Age.

Lalueza-Fox said light-skinned Europeans emerged “much later” than once believed — possibly only in the Neolithic era when hunter-gatherers became farmers.

The cause, he said, may have been a change in diet and lower vitamin D intake associated with this lifestyle change.

In the absence of natural vitamin D, the human skin can produce its own in contact with the sun. Dark skins synthesize much less than fair ones, creating an evolutionary incentive for change.

In La Brana 1, Lalueza-Fox and his team also found the genetic signature for blue eyes and dark hair.

While the exact hue of skin cannot be determined, the scientists say its combination with blue eyes is not found in modern Europeans today.

Man’s oldest common forefather was dark-skinned, and people became paler as they moved out of Africa into colder climates with less sunlight.

Subsequent migrations and mixing created the wide range of hues we have today.

La Brana’s genome is the first of a European hunter-gatherer to be fully sequenced. It was found to be most closely related to today’s northern Europeans.

The probe also found that La Brana 1 had not yet acquired the genetic mutation that allowed later humans to digest milk and starch more easily — an adaptation that probably coincided with the birth of agriculture.

The authors said more Mesolithic genomes will have to be analyzed to determine how widespread La Brana’s genomic traits really were.