The Bubonic Plague, also known as the Black Death, killed up to half of Europe in the 1300s. Thankfully, it’s a thing of the past — or is it? Geneticists now think the plague changed human DNA in ways that can still be felt today: 700 years later. The World’s host Marco Werman speaks to Luis Barreiro, a population geneticist at the University of Chicago, about his new study in Nature magazine.