Archaic Introgression Shaped Human Circadian Traits

Area of Science:

• Human evolution
• Genetics
• Chronobiology

Background:

• Modern humans interbred with archaic hominins (Neanderthals, Denisovans) after migrating from Africa.
• Archaic DNA introgression may have facilitated adaptation to Eurasian environments.
• The role of archaic introgression in human circadian biology and chronotypes is largely unknown.

Purpose of the Study:

• To investigate differences in circadian gene regulation between archaic and modern humans.
• To determine if archaic introgression adaptively contributed to human chronotypes.

Main Methods:

• Genome-wide analysis of archaic hominin and modern human genomes.
• Identification of variants in circadian genes affecting splicing and regulation.
• Analysis of introgressed variants' association with gene expression and chronotype.

Main Results:

• Identified 28 circadian genes with potential splicing alterations and 16 with divergent regulation in archaic hominins.
• Found introgressed variants enriched in circadian gene expression quantitative trait loci.
• Observed significant associations between introgressed alleles and chronotype, particularly increased morningness.

Conclusions:

• Archaic hominin introgression significantly influenced human circadian gene regulation and chronotype.
• Introgressed variants likely contributed to adaptive changes in human chronotypes, possibly related to high-latitude adaptation.
• Specific circadian loci show evidence of adaptive introgression and latitudinal clines in allele frequency.