TITLE: “Inferring positive selection in the human gut microbiome using signatures of genetic linkage.”
ABSTRACT: The human gut microbiome is composed of hundreds of simultaneously evolving species that can affect human health. However, fundamental features of genetic diversity have yet to be leveraged to identify genes that contribute towards microbial adaptation. One such feature is the statistical association of mutations, otherwise known as linkage disequilibria. In this seminar, I will describe how patterns of linkage disequilibria can reflect the direction of selection in microbial populations. I will then demonstrate how linkage can provide insight into the degree of positive and negative selection as well as the targets of adaptation across human microbiomes. Finally, I will compare patterns of linkage disequilibria across hosts to the co-occurrence of mutations within a host. In sum, the ability to examine linkage among large cohorts for many species provides an opportunity for researchers to examine novel patterns that are indicative of certain evolutionary dynamics.