Genetic and climatic factors in the dispersal of Anatomically Modern Humans Out of Africa

Abstract

The evolutionarily recent dispersal of Anatomically Modern Humans (AMH) out of Africa and across Eurasia provides an opportunity to study rapid genetic adaptation to multiple new environments. Genomic analyses of modern human populations have detected limited signals of strong selection such as hard sweeps, but genetic admixture between populations is capable of obscuring these patterns and is well known in recent human history, such as during the Bronze Age4. Here we show that ancient human genomic datasets contain multiple genetic signatures of strong selection including 57 hard sweeps, many with strong associations with cold adaptation. Similar genetic signatures of adaptation are also observed in adaptively-introgressed archaic hominin loci, as well as modern Arctic human groups. Consistent targets include the regulation of fat storage, skin physiology, cilia function and neural development; with multiple associations to modern western diseases. The spatiotemporal patterns of the hard sweeps allow reconstruction of early AMH population dispersals, and reveal a prolonged period of genetic adaptation (~80-50,000 years) following their initial out of Africa movement, before a rapid spread across Eurasia reaching as far as Australia.

The Persian plateau served as hub for Homo sapiens after the main out of Africa dispersal

“…A certain amount of time would have been necessary to demographically recover from the OoA bottleneck; and new environmental stressors had to be dealt with either with biological adaptation (see Supplementary Note 1; Supplementary Fig. 14, Supplementary Data) 85 or by developing technological innovations, as testified by the archaeological record. Finally, ecological stressors, exemplified by changes in habitat connectivity and the interaction with local archaic groups might have also played an important role.…”

Reconstructing Contact and Potential Interbreeding Geographical Zone for Neanderthals and Anatomically Modern Humans

“…Before this study, our understanding of the interbreeding of AMH and Neanderthal was based on genetic data alone (Tobler et al 2023). Here for the rst time, we applied SDMs as additional and independent line of information to locate possible geographic location of the two species interbreeding.…”