This is Scientific American ― 60-Second Science. I'm Christopher Intagliata.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 their actual genetic ancestry.So that showed us 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."Kaustubh Adhikari, who studies human genetics at University College London.In particular, lighter-skinned volunteers tended to overestimate their European ancestrywhereas darker-skinned subjects overestimated their Native American or African backgrounds.Now a new study by Adhikari and his colleagues offers a reason for the mismatch.The skin color data and the DNA sequences led the researchers to identify a genetic variant for lighter skin that arose in Asia 20- to 30-thousand years ago.That event appears to be independent of the evolution of lighter skin in Europe.