An article in National Geographic Magazine for July 2013 gives a fascinating insight into the history of our species homo sapiens and our ‘cousins’, the Neanderthals and Denisovans. Excavations in the Denisova cave in the Altai mountains of Siberia indicates that all three species co-existed in the region some 40,000 years ago.
The story begins with the find of a arm ring of polished stone, undoubtedly made by a representative of homo sapiens. Further excavation in the same layer uncovered a bone which turned out to be a little finger. DNA analysis by the Max Planck Institute in Leipzig, gave the surprising result that the finger belonged to a young girl of the Denisovan species.
Later on two teeth were found which also turned out to be Denisovan. Then a toe was uncovered and DNA analysis showed this to be Neanderthal.
It is suggested that the Neanderthals and Denisovans developed from a common ancestor, homo heidelbergensis, some 500,000 years ago. When these left Africa the Neanderthals migrated to Europe while the Denisovans spread to Asia. Later on the two species mated with homo sapiens when this last species left Africa between 70,000 and 40,000 years ago