Neandertal and Denisovan Genomes and What They Tell Us

The study of the genomes of our closest extinct relatives allows for insights into the recent evolutionary history of anatomically fully modern humans. The discovery of ancient remains with extraordinary preservation from a cave in the Altai mountains allowed us to generate high coverage genomes sequences from two archaic human individuals, a Neandertal and a Denisovan.  The analysis of these genomes reveals that that they are more closely related to one another than they are to modern humans. At least two events of gene flow from these groups into modern humans have been found; Neandertal admixture has been detected into all out-of-Africa populations while Denisovan gene flow likely occurred to the common ancestors of Australians and New Guineans. The high quality sequences of a Denisovan and a Neandertal individual also allows for analyses of gene flow into the archaic lineages. We found evidence for two gene flow events into Denisovans: Gene flow from Neandertals and gene flow from an hitherto unknown group of archaic humans. Taken together, these results show that gene-flow was not uncommon among human groups in the Pleistocene.