Adaptive introgression in modern human circadian rhythm genes.

Interbreeding between modern humans and archaic hominins, including Neanderthals and Denisovans, occurred as modern humans migrated outside of Africa. Here, we report on evidence of adaptive introgression from archaic hominins within genomic regions associated with circadian rhythm cycling, chronotype, and sleep using 76 worldwide modern human populations from the Human Genome Diversity Project and 1000 Genomes Project. We identified 265 independent segments suggestive of adaptive introgression, where 22 of these segments show evidence of positive selection. We tested for evidence of a latitudinal cline within 35 core haplotypes, finding no clear latitude gradient, and identified the likely archaic donor for each of these haplotypes. We found that several genes with evidence of adaptive introgression are associated with affective disorders, chronotype, and respiratory diseases. Lastly, many of the variants are eQTLs for several genes that are significantly enriched in immunity pathways.