ADELAIDE, AUSTRALIA—Denisovans are known from the genetic analysis of a finger bone discovered in the Altai Mountains of northern Asia, but little of their DNA has been found in other ancient human specimens or modern populations in mainland Asia. However, Denisovan DNA has been detected in modern human populations in Australia, New Guinea, and surrounding areas. Alan Cooper of the University of Adelaide and Chris Stringer of London’s Natural History Museum propose that this pattern can be explained if the Denisovans managed to cross Wallace’s Line, a powerful marine current off the east coast of Borneo that blocked the migration of other creatures. “The key questions now are where and when the ancestors of current humans, who were on their way to colonize New Guinea and Australia around 50,000 years ago, met and interacted with the Denisovans,” Cooper added.