Teeth from long-dead people and animals are divulging the history of modern-day pathogens.Ancient DNA extracted from the teeth of humans who lived long ago is yielding new information about pathogens past and present. In one of the latest studies, researchers uncovered and sequenced ancient herpes genomes for the first time, from the teeth of long-dead Europeans. The strain of herpes virus that causes lip sores in people today — called HSV-1 — was once thought to have emerged in Africa more than 50,000 years ago. But the new data, published in Science Advances on 27 July1, indicate that its origin...