Neanderthal mother, Denisovan father

Thomas Higham/University Of Oxford The valley where the Denisova cave is located, in southwestern SiberiaThomas Higham/University Of Oxford

A 13-year-old girl who lived 90,000 years ago in what is now southwestern Siberia is the first described case of a direct descendant of two distinct archaic human groups. Her mother was Neanderthal and her father was Denisovan. Neanderthals and Denisovans belong to the genus Homo, just like modern humans. Expert opinion, however, is divided. Some consider Neanderthals, which lived in Europe and part of Asia between 430,000 and 40,000 years ago, as a different species to present humans, while others believe they were a subspecies. The same goes for the Denisovans, about whom we know less. Bone fragments belonging to this group were only discovered for the first time in 2008, in the Denisova cave in the Altai mountains, a region of Siberia near Kazakhstan. Neanderthal remains, meanwhile, have already been identified across Europe and Asia. The cave in Siberia is the only archaeological site where Denisovans have been found. A group led by paleogeneticist Svante Pääbo, from the Max Planck Institute in Germany, analyzed a bone fragment and found that the girl, nicknamed Denny, was a direct descendant of both groups (Nature, August 22). “We shy away a little from the word ‘hybrid’,” Pääbo told the journal Nature. Such a term would imply that Neanderthals and Denisovans are distinct species. Denny’s DNA indicates that her mother was more closely related to Neanderthals who lived 55,000 years ago in the area of present-day Croatia than those who inhabited the Siberian caves 120,000 years ago. It is not known whether there were late migrations of Neanderthals from Europe to Asia before Denny was born, or whether Neanderthals took the opposite route afterward. Pääbo believes Neanderthals and Denisovans probably procreated frequently.