What types of disease dynamics result in elevated rates of adaptation?

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Sarah Jo McGeady

Mentor: Dr. Lawrence Uricchio, Department of Biology, Tufts University.

Date/Time: August 24, 2021 at 2:40pm

Abstract: Recent literature has explored the intersection between epidemiology and evolution by analyzing the effects of pathogens on molecular evolution.   Substitution rates in a host organism’s pathogen-interacting genes  may be influenced by pathogens, as these genes are under pressure to evolve and escape these interactions.This project aimed to model how  the dynamics of infectious disease transmission  affect adaption rates in highly conserved genes.. Many pathogen interacting genes are highly conserved, suggesting that alleles that are beneficial in the context of an epidemic (i.e., disease resistance or tolerance alleles) may be deleterious in the absence of pathogen pressure. Such context-dependent selection pressures could result in partial selective sweeps, frequency dependent selection, and distortions to the site frequency spectrum. We hypothesized that selection would favor alleles with intermediate effects on disease resistance, because they would be only moderately deleterious in the absence of infection. Simulations were performed to explore how fixation rates vary as a function of selection coefficient in an eco-evolutionary disease transmission model.