If you’re white, live in the United States, and a distant relative has uploaded their DNA to a public ancestry database, there’s a good chance an internet sleuth can identify you from a DNA sample you left somewhere. That’s the conclusion of a new study, which finds that by combining an anonymous DNA sample with some basic information such as someone’s rough age, researchers could narrow that person’s identity to fewer than 20 people by starting with a DNA database of 1.3 million individuals.
Such a search could potentially allow the identification of about 60% of white Americans from a DNA sample—even if they have never provided their own DNA to an ancestry database. “In a few years, it’s really going to be everyone,” says study leader Yaniv Erlich, a computational geneticist at Columbia University.