A molar discovered in a cave in Laos shows where the enigmatic Denisovans could have interbred with the ancestors of modern humans. A tooth found inside of a mountain cave in Laos has solved one of the biggest scientific mysteries of the Denisovans, a branch of ancient humans that disappeared roughly 50,000 years ago. Since 2010, when Denisovan teeth and finger bones were first discovered, DNA testing has revealed that the enigmatic hominins were among the ancestors of people alive today in Australia and the Pacific. But scientists didn’t understand how the Denisovans, whose scant remains had been found only...