The Scariest Story Never Told

The results from the human genome study reject the null model of no admixture and allow us to infer that contemporary African populations contain a subset proportion of genetic material (≈22%) that introgressed ≈35 kya from an archaic population that split from the ancestors of anatomically modern humans (primitive ape men)≈700 kya. Three candidate regions showing deep haplotype divergence, unusual patterns of linkage disequilibrium, and small basal clade size are identified and the distributions of introgressive haplotypes surveyed in a sample of populations from across sub-Saharan Africa. One candidate locus with an unusual segment of DNA that extends for >31 kb on chromosome 4 seems to have introgressed into modern Africans from a now-extinct taxon (closest known by most would be the famous “Lucy”) that lived in central Africa. Taken together our results suggest that polymorphisms present in extant populations introgressed via relatively recent interbreeding with hominin forms that diverged from the ancestors of modern humans in the Lower-Middle Pleistocene (lasted from c. 2.58 million to 11,700 years ago).