Evolutionary dynamics and ecological diversification in rapidly adapting populations
Monday, February 5, 2018 - 12:00pm
Joseph Henry Room, Jadwin Hall
CUNY-Princeton Biophysics Seminar
Physics and the Lewis-Sigler Institute

Underneath the fascinating biology, evolution is governed by a stochastic dynamical process, which describes how mutations arise and spread through a population. Though the basic rules of this process are simple, it is often surprisingly difficult to predict how they combine to determine the genetic composition of a population. In the first part of my talk, I will discuss some of the key challenges involved in modeling evolutionary dynamics from a statistical physics perspective, and I will describe some recent theoretical advances that allow us to predict these dynamics in simple models of genome evolution. I will then discuss our recent experimental effort to measure the dynamics of molecular evolution in a 60,000-generation experiment in E. coli, by sequencing the metagenomes of its frozen “fossil record”. The second part of my talk will focus on a key finding that emerged from this study: the evolution of primitive ecological interactions and the breakdown of competitive exclusion. I will introduce a simple, empirically motivated model for describing these coupled ecological and evolutionary processes, which allows us to understand the dynamic balance between the creation of new “species” and the tendency for fitter strains to take over the population. Finally, I will briefly discuss extensions to the more diverse microbial communities found in nature, and how similar evolutionary processes can be inferred using data from the gut microbiome.