As well as examining how human fossils look, it's also now possible to scan them for DNA. In 2010 this is what happened to a 41,000 year old finger bone discovered in the Altai Mountains in southern Siberia, near the border with Asia.
Once the DNA analysis was complete, few could have guessed the outcome. The DNA fell outside of the modern human range: here was a new species of archaic human—one previously unknown to science.
Calling this species the Denisovans, scientists then scoured the DNA of modern populations worldwide, looking for evidence of past interbreeding with Denisovans. They found it—across Asia people today possess between 1 - 5% Denisovan DNA.
Find out how acquiring genes from archaic humans already living in Asia may have helped modern human newcomers survive there.