Mutation-accumulation lines of evolved Escherichia coli populations

As organisms regularly encounter complex scenarios in nature, testing the generality of the drift-barrier hypothesis and studying the dynamics of mutation-rate evolution are thus critical to understanding and predicting the evolutionary dynamics of natural populations. To address these issues, we used experimentally evolved Escherichia coli lines as a model system to understand the effects of population-size alterations and fluctuating resource availability on the dynamics of mutation-rate evolution. Using a direct method to quantify the mutation rate, mutation-accumulation coupled with whole-genome sequencing (MA/WGS), we assayed 44 experimental clones across 22 representative populations. About 1,200 MA lines were sequenced.