Diets and Microbes in Primates

Human microbiomes, or communities consisting of the microorganisms that live in, on, and around us, have profound effects on health, disease, and normal host function. The intestinal microbiome is an especially important "partner" in dietary adaptations, functioning to convert foods and food components that are otherwise inaccessible into useful nutrition to the benefit of the host organism. Our project explores the nature of the primate microbiome with the goal of understanding the impacts of microbiomes on human evolution. Taxonomic comparative analyses of intestinal microbiomes (mainly bacterial microbes) using high throughput sequencing of ribosomal DNA (16S rDNA) enable identification of microbial taxa residing in the primate gut, permitting us to explore ties between microbial communities and diet. Moreover, we conduct analyses of functional microbial genes to determine how microbes contribute to dietary adaptations. While the taxonomic composition of the primate intestinal microbiome is similar across primate species, the relative proportions of microbial taxa vary according to the host’s diet, phylogenetic history, and environmental quality. Functional data show that nonhuman primate microbial taxa play larger roles in protein metabolism than do microbes residing in the human gut. In general, our results point to important contributions of microbial ecosystems to the evolution of human diet. We also see implications for human brain evolution through energy and micronutrients that are produced by microbial taxa.