RT Journal Article SR Electronic T1 Recovering signals of ghost archaic admixture in the genomes of present-day Africans JF bioRxiv FD Cold Spring Harbor Laboratory SP 285734 DO 10.1101/285734 A1 Arun Durvasula A1 Sriram Sankararaman YR 2018 UL http://biorxiv.org/content/early/2018/03/21/285734.abstract AB Analyses of Neanderthal and Denisovan genomes have characterized multiple interbreeding events between archaic and modern human populations. While several studies have suggested the presence of deeply diverged lineages in present-day African populations, we lack methods to precisely characterize these introgression events without access to reference archaic genomes. We present a novel reference-free method that combines diverse population genetic summary statistics to identify segments of archaic ancestry in present-day individuals. Using this method, we find that 7.97 ±0.6% of the genetic ancestry from the West African Yoruba population traces its origin to an unidentified, archaic population (FDR ≤20%). We find several loci that harbor archaic ancestry at elevated frequencies and that the archaic ancestry in the Yoruba is reduced near selectively constrained regions of the genome suggesting that archaic admixture has had a systematic impact on the fitness of modern human populations both within and outside of Africa.