Adaptations to Climate-Mediated Selective Pressures in Humans

TLDR

Humans inhabit a remarkably diverse range of environments, and adaptation through natural selection has likely played a central role in the capacity to survive and thrive in extreme climates. The study aims to identify selection signals in the human genome by correlating allele frequencies with climate across 61 worldwide populations. This is achieved by scanning the genome for SNPs with the strongest correlations between allele frequencies and climate variables. The analysis reveals a striking enrichment of genic and nonsynonymous SNPs correlated with climate, many overlapping GWAS hits for pigmentation and autoimmune diseases, and enriched gene sets related to UV radiation, infection, immunity, and cancer, implying climate‑driven adaptation shapes the spatial distribution of human genetic variation.

Abstract

Humans inhabit a remarkably diverse range of environments, and adaptation through natural selection has likely played a central role in the capacity to survive and thrive in extreme climates. Unlike numerous studies that used only population genetic data to search for evidence of selection, here we scan the human genome for selection signals by identifying the SNPs with the strongest correlations between allele frequencies and climate across 61 worldwide populations. We find a striking enrichment of genic and nonsynonymous SNPs relative to non-genic SNPs among those that are strongly correlated with these climate variables. Among the most extreme signals, several overlap with those from GWAS, including SNPs associated with pigmentation and autoimmune diseases. Further, we find an enrichment of strong signals in gene sets related to UV radiation, infection and immunity, and cancer. Our results imply that adaptations to climate shaped the spatial distribution of variation in humans.