How Diet Has Shaped Human Genome Patterns Worldwide

Abstract (English)

Human populations have experienced dramatic shifts in subsistence patterns exerting strong selective pressures over the metabolic pathways involved in food digestion. While these dietary changes could have occurred in the ancient evolutionary past, evidence for subsequent adaptations can be characterized through unique population genetic variation contextualized with environmental factors, cultural behaviors, and phenotypic features. Here, I analyzed global populations from publicly available 1000 Genomes Project dataset spanning five continents including Europe, Asia, Africa, and the Americas. This analysis applied several selection scan statistics including XP-nSL, nSL, and PBS to investigate genetic patterns of evolutionary adaptations to dietary changes that are still present within these modern-day populations. From the top 1% of these results, genes showing the strongest signature of selection related to metabolic pathways and diet were further examined for their functional impact. Special attention was applied to candidate genes that have been previously related to dietary genetic adaptations such as AMY1 or MGAM (starch), LCT (lactase), SGLT1 (glucose), and PRSS1, FADS, CPT1A (protein). For highly admixed populations, such as populations in the Americas, local ancestry was also considered for these loci to determine their evolutionary origin. Importantly, identifying novel population genetic diversity stemming from evolutionary dietary mismatches can represent candidate loci for the treatment of related metabolic disorders that are prevalent today. These results highlight the utility of identifying novel gene loci that sit at the intersection of nutrient consumption and metabolic syndromes to better understand the evolutionary histories of health-related traits.