Fig. 2

The average competitive fitness deficit (in black, error bars are 95% confidence intervals) of the mutator strain relative to the wild type, expressed as selection coefficient, is 2.3%. Fitness competitions were conducted in a series of eight blocks, shown in gray. The two strains were not competed directly against each other; within each block, each was competed separately against an otherwise isogenic MMR+ YFP+ strain. Each block contained between 6 and 8 replicate competitions