Rapid evolution in complex microbial communities

Microbial communities have an enormous capacity for rapid evolutionary change: a single person's gut microbiome, for example, produces more than a billion new mutations every day. Predicting the fates of these new mutations can be challenging, since they must compete within a complex environment comprising large numbers of ecologically interacting strains. In this talk, I will describe some of our recent theoretical efforts to address this problem, bridging the scales between population genetics and community ecology. I will describe our recent efforts to predict the coupled ecological and evolutionary dynamics that emerge in minimal models of resource competition, and their connections to empirical data from laboratory evolution experiments and mammalian gut microbiomes. We will see that several counterintuitive behaviors arise in the high-diversity limit that characterizes many natural microbial populations, and that "large-N" approaches can be useful for understanding these self-organized dynamical states.