Date: May 17, 2022
Speaker: Dr. Cameron Browne
Affiliation: University of Louisiana at Lafayette
Title: Connecting evolutionary genetics and ecological dynamics with multi-strain pathogen models
Abstract: Integrating ecological and evolutionary dynamics presents a challenging problem for rapidly evolving pathogens. For example, during HIV infection, the virus escapes several immune response populations via resistance mutations at distinct epitopes (proteins coded in viral genome), precipitating a dynamic network of interacting virus and immune variants. While the virus-immune interactions may be quite complex, I will talk about recent work to link pathogen population genetics with dynamics theoretically and through data to characterize their evolution. We start with a general ecosystem model of multiple virus and immune populations, and show how different stable and persistent equilibrium structures emerge in the virus-immune network. Using binary sequences to code viral strain resistance to immune responses, we prove that bifurcations are determined and simplified by a certain measure of epistasis in the viral fitness landscape. Next, I present collaborative projects where the “eco-evolutionary” modeling framework is applied to phylogenetic and population data for simian immunodeficiency virus (SIV) – immune trajectories and mixed (host and aquatic) replication of Cholera in Haiti. The mathematical models recapitulate the data and motivate ongoing work on jointly deciphering population genetics and dynamics of complex pathogen ecosystems.