Europeans Weren’t Always Pale: DNA Shows How Light Skin Evolved

BOSTON — White skin might seem like a European trademark, tied to centuries of division and pride, but a new study says it’s a recent arrival. Geneticists at Harvard University, led by Dr. Iain Mathieson, dug into ancient DNA and found that early Europeans were dark-skinned for way longer than we thought. Their research, shared at the American Association of Physical Anthropologists’ 84th annual meeting and posted on BioRxiv, explains how and when light skin showed up.

Scientists used to think skin lightened soon after humans left Africa 40,000 years ago, adjusting to Europe’s weaker sunlight. Nope. DNA from hunter-gatherers in Spain, Luxembourg, and Hungary—8,500 years old—shows they kept dark skin. Then, about 7,800 years ago, everything changed. Farmers from the Near East (think modern Turkey) moved in, carrying two key genes: SLC24A5 and SLC45A2. These genes flip a switch in the body, cutting down melanin—the pigment that darkens skin—and making it lighter.

Here’s how it happened: those farmers started families with the dark-skinned locals. The SLC24A5 gene, which lightens skin by 25-40 percent, spread quickly through southern and central Europe as their kids and grandkids multiplied. Later, around 5,800 years ago, the SLC45A2 gene kicked in, making skin even paler. It’s like a two-step recipe—first one gene mixed in, then the other took hold, turning Europeans’ skin lighter over generations.

There’s more. In Sweden, 7,700-year-old bones from Motala show some hunter-gatherers already had both genes, plus one for blue eyes. They didn’t wait for the farmers—they might’ve gotten these traits from distant relatives in East Asia, hinting at unexpected ancient travel. Meanwhile, farmers kept spreading SLC24A5 across Europe, and by 5,800 years ago, SLC45A2 was everywhere, sealing the deal on pale skin.

“This isn’t the simple story we imagined,” Mathieson said. “DNA lets us watch evolution unfold.” Pennsylvania State’s Nina Jablonski, not part of the study, told Science it’s “fun” proof of recent change. So, light skin? It’s thanks to genes SLC24A5 and SLC45A2, handed down from Near Eastern farmers and mixed into Europe’s gene pool, step by step, starting just 7,800 years ago.

(Source: Presented at the 84th annual meeting of the American Association of Physical Anthropologists, published on BioRxiv)