Scientists Spot Genes Behind Skin Color

From - October 12, 2017

Scientists Spot Genes Behind Skin Color

THURSDAY, Oct. 12, 2017 -- Humans come in a range of colors, and new research is getting a step closer to how that happens.

Newly identified gene variants tied to skin colors among Africans could offer insights into human evolution. The findings could also boost scientists' understanding of skin cancer and other conditions, researchers say.

"We have identified new genetic variants that contribute to the genetic basis of one of the most strikingly variable traits in modern humans," said study senior author Sarah Tishkoff. She's professor of genetics and biology at the University of Pennsylvania.

Until now, only a few genes linked with normal variation in skin color have been pinpointed. Most of them have been found in studies of Europeans.

In this study, researchers assessed skin pigmentation and genetic data from nearly 1,600 ethnically and genetically diverse people in Africa.

"When people think of skin color in Africa, most would think of darker skin, but we show that within Africa there is a huge amount of variation, ranging from skin as light as some Asians to the darkest skin on a global level and everything in between," Tishkoff said in a university news release.

"We identify genetic variants affecting these traits and show that mutations influencing light and dark skin have been around for a long time, since before the origin of modern humans," she noted.

"Skin color is a classic variable trait in humans, and it's thought to be adaptive," Tishkoff said. "Analysis of the genetic basis of variation in skin color sheds light on how adaptive traits evolve, including those that play a role in disease risk."

There are benefits to both light and dark skin. For example, darker skin is believed to help provide some protection against the sun's ultraviolet rays. Africans do not often develop the deadliest skin cancer, melanoma, the researchers said.

On the other hand, lighter skin improves sunlight-triggered vitamin D in regions with lower amounts of sunlight, the study authors added.

Most of the skin color-linked genetic variants identified in the study appear to have originated more than 300,000 years ago. Some emerged roughly 1 million years ago, well before the advent of modern humans, according to the report.

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