This is Scientific American's 60 Second Science.

I'm Christopher Intagiyata.

In Latin America, Native Americans, Africans, and Europeans have intermixed for centuries.

So a few years back, researchers sought to learn more about the ancestry

of more than 7,300 people from Brazil, Chile, Colombia,

Mexico, and Peru.

The volunteers provided DNA samples,

and they also answered the question,

what do you think your background is?

Turns out that what they thought,

that is their predicted ancestry, told a different story than their genes did,

with skin color a key factor.

Their predicted ancestry is actually very well correlated with their skin color but poorly

correlated with the actual genetic ancestry.

So that showed us that people are actually trying to predict their whole ancestry by just

looking at their skin color, which is a pretty crude thing to do, but that's how the attitude is in

Latin America.

Kosto Badikari, who studies human genetics at University College London.

In particular, lighter skin volunteers tended to overestimate their European ancestry,

whereas darker skin subjects overestimated their Native American or African backgrounds.

Now a new study by a Decory and his colleagues offers a reason for that

mismatch. The skin color data and the DNA sequences led the researchers to

...