Helen Alexander

Mutations generate genetic variation in populations, providing the raw material on which natural selection can act. Mutation rate is therefore a critical evolutionary parameter. However, past work has typically assumed that the mutation rate is uniform. In contrast, recent advances in experimental techniques have revealed that mutation rates in bacterial populations vary amongst individuals and over time, particularly when exposed to environmental stressors. Past theoretical work suggests these heterogeneities could be relevant for the rate of adaptations requiring multiple mutations. In this talk I will describe our recent efforts to extend mutation rate estimation methods to account for these heterogeneities. Specifically, we focus on developing models and inference methods suitable for fitting to mutant count data from fluctuation assays, a classic and still widely-used experimental technique to estimate mutation rates in microbial populations.