Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology
March 28, 2019 10:30, CC Ballroom A
Genetic evidence has emerged that Denisovans and Neandertals have interbred both with the ancestors of modern non-Africans, and with each other. As a consequence, the genomes of many modern and ancient individuals harbor long fragments of DNA inherited from widely diverged populations. The presence of this "introgressed" DNA can be inferred through genome-wide signatures such as f4 statistics, but identifying specific fragments of introgressed DNA presents additional challenges.
We developed methods for identifying such fragments in modern humans, and identified Denisovan and Neandertal DNA in 1523 geographically diverse individuals. From this introgressed DNA we and others have discovered signatures of both positive and negative selection, and learned about the history of interactions between modern humans and our archaic cousins. However, despite evidence of similar interactions between Neandertals and Denisovans, it has not been possible to identify specific introgressed DNA fragments in either population.
Here, I will review these results, and discuss the genome of an individual from Denisova Cave (“Denisova 11”), with a Neandertal mother and a Denisovan father. The unique nature of this individual's genome allows us to identify introgressed fragments present in either parent, which would appear as homozygous tracts of Neandertal or Denisovan DNA. Strikingly, we identify only Neandertal homozygous regions, indicating that the Denisovan father inherited DNA from a distant Neandertal ancestor. From these regions, we infer that this Neandertal ancestor came from a different population than the Neandertal mother of Denisova 11.
Max Planck Society; the Max Planck Foundation (31-12LMP Pääbo to S.Pä.); the European Research Council (694707, 324139, 715069); Russian Science Foundation (14-50-00036 to M.B.K., M.V.S. and A.P.D.).