Speaker
Description
Stochastic establishment of adaptive genotypes (survival and outgrowth of initially rare lineages) is a key step in evolutionary rescue. Despite featuring in theoretical models, this process has received little attention in experimental biology. Here I will describe how we can quantify the probability of establishment with low-tech, high-throughput experimental assays combined with statistical inference. I will present an application to establishment of resistant bacteria (Pseudomonas aeruginosa) under antibiotic treatment, an example of evolutionary rescue in medical contexts. Our experiments support the theoretical expectation that, despite a positive average population growth rate, establishment from single individuals frequently fails. Moreover, we find that the surrounding, initially large, antibiotic-sensitive population can either inhibit or (surprisingly) facilitate establishment of resistance. More broadly, bacteria could provide a relevant experimental system for studying the role of biotic interactions in evolutionary rescue.