A map of local adaptation in Arabidopsis thaliana

Local adaptation is critical for species persistence in the face of rapid environmental change, but its genetic basis is not well understood. We identified candidate loci for local adaptation in the plant Arabidopsis thaliana from a genome-wide association study of lifetime fitness in geographically diverse accessions grown in field experiments in four sites across the species’ native range. Fitness-associated loci exhibited both geographic and climatic signatures of local adaptation. High-fitness alleles were generally distributed closer to the site where they increased fitness than genomic controls, occupying specific and distinct climate spaces. Independent loci with different molecular functions contributed most strongly to fitness variation in each site. Independent local adaptation by distinct genetic mechanisms may facilitate flexible evolutionary response to changing environment across a species range.