Archaeologists and paleoanthropologists discovered a tooth and a finger bone in the Denisova cave in the Altai Mountains a few years ago. They extracted DNA from these, and made the discovery that this was another archaic form of human that was previously unknown, and also very closely related to us, and also to Neandertals.
Further studies have confirmed that they also mated with modern humans, as well as Neandertals.
Now, the full genome has been sequenced.
It is quite amazing that the science of genetics is rewriting the history of our big, human family, and fills in the gaps where the archaeological record cannot tell the story, nor morphology and comparative anatomy.



