Dietary adaptation of FADS genes in Europe varied across time and geography

Fatty acid desaturase (FADS) genes encode rate-limiting enzymes for the biosynthesis of omega-6 and omega-3 long chain polyunsaturated fatty acids (LCPUFAs). This biosynthesis is essential for individuals subsisting on LCPUFAs-poor, plant-based diets. Positive selection on FADS genes has been reported in multiple populations, but its presence and pattern in Europeans remain elusive. Here, with analyses of ancient and modern DNA, we demonstrated that positive selection acted on the same FADS variants both before and after the advent of farming in Europe, but on opposite alleles. Selection in recent farmers also varied geographically, with the strongest signal in Southern Europe. These varying selection patterns concur with anthropological evidence of differences in diets, and with the association of recently-adaptive alleles with higher FADS1 expression and enhanced LCPUFAs biosynthesis. Genome-wide association studies revealed associations of recently-adaptive alleles with not only LCPUFAs, but also other lipids and decreased risk of several inflammation-related diseases.