A new scientific study challenges the use of skin color as a classifier for race

Image: Reuters/Phil Noble
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At the heart of white supremacist ideology is the belief that people of different races are biologically distinct, and people with very pale skin colors belong to a superior race that evolved from people with darker skin.

But findings from a recent scientific study strike a powerful blow to this myth. The study, published in Science, challenges the use of skin color as a classifier for race at all.

Nicholas Crawford and Sarah Tishkoff at the University of Pennsylvania in Philadelphia studied the genetics of skin color in over 1,500 African participants and compared the results to the hundreds of studies of skin color in Europeans. Researchers recruited volunteers from 10 ethnic groups living in Ethiopia, Tanzania, and Botswana and took their DNA samples and measured their skin pigmentation.

Once researchers combined and combed through the data, they were able to find eight sites in the human genome that are associated with skin color. These eight sites accounted for nearly 30% of the variation in skin color among the volunteers. Researchers found variants associated with paler skins and those associated with darker skin.

The study showed that seven paler skin variants are thought to have arisen at least 270,000 years ago; with four emerging more than 900,000 years ago. These variants for pale skin predated the arrival of Homo sapiens (who are estimated to have emerged from Africa 300,000 years ago).

The findings may come as a surprise to some. Researchers have long believed that variants for darker skin color are somewhat fixed for people of African descent, while variants for lighter skin color emerged later on once humans settled outside of Africa. But the study points at what may seem obvious; skin color in Africa can vary widely, with lighter or darker skin pigments found across the continent. While the San hunter-gatherers of Botswana have lighter skin variants comparable to some East Asians, the Nilo-Saharan pastoralists from East Africa have some of the darkest skins around.

When looking at the darker-skin variants, researchers found that some variants evolved much more recently than initially thought. That is to say that participants with particularly dark skins may have gained the trait more recently from paler ancestors. Once again, this challenges the view that paler skin variants are more recently evolved, whilst darker skin variants remained constant and fixed in Africa. The study also suggests that some people with darker skin also carried a gene for lighter skinned variants, but though they don’t show it, they still carry a trait found within their population.

For researchers, the study blows away the biological concept of race all together. These variants for lighter or darker skin color don’t neatly fit into discrete groups or boundaries.

Most interestingly, researchers say they wouldn’t have been able to come to this conclusion had they not made the conscious decision to carry out their study in Africa. Researchers have previously focused predominantly on European descent—it wasn’t until they broadened their scope that they were able to piece together the puzzle of what unites us.