Neanderthal genes shifted modern humans toward morning wakefulness
DNA inherited from Neanderthals and Denisovans altered circadian rhythms in modern humans, according to a 2023 study in Genome Biology and Evolution. Researchers analyzed archaic hominin genomes and found 28 circadian genes carrying variants that could change gene splicing and 16 genes with different regulatory patterns compared to present-day humans. Among those, CLOCK, PER2, RORB, RORC, and RORA stood out. Introgressed alleles appeared more often among regulatory variants affecting circadian genes, and many of those alleles were linked to chronotype. The strongest effects pushed people toward morningness. Several loci showed signs of adaptive introgression or frequency gradients tied to latitude.
The findings suggest archaic ancestry helped modern Eurasian populations adapt to seasonal light variation at higher latitudes after migrating out of Africa.
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