题 目: Effects of gene transfer in phage-host coevolution
Kavli Institute for Theoretical Physics, UC Santa Barbara
时 间: 4月6日（周四）13:00-14:00
主持人: 林杰 研究员
Bacterial hosts and phages have been in an ongoing arms race for billions of years, leading to the evolution of various antiphage defense and corresponding counter-defense systems. Recent studies have revealed the arsenal for defense and counter-defense systems is much more diverse than previously expected. Individuals can only carry a small portion of all systems due to the constrained genome size of phages and potential fitness burdens on hosts. However, both hosts and phages frequently lose and gain defense and counter-defense systems through gene transfer.
The role of the rapid turnover of these systems in host-phage coevolution is still poorly understood. We develop stochastic Lotka-Volterra models incorporating gene transfer processes to investigate this problem. The system exhibits distinct dynamical behaviors at different gene transfer rates. Our analytical result shows low gene transfer rates are sufficient to maintain genetic diversity above stochastic fluctuations, demonstrating their importance in stable coexistence of diverse phages and hosts.