Fig. 4.

Pairwise competitions. Each bar represents a series of approximately 12 identical cultures. Gray indicates the fraction won by the wild-type strain by day 18, and black indicates the fraction won by the strain noted beneath it. Clusters of bars indicate identical types of competitions carried out with independently transformed isolates of each competitor strain. (A) Competitions between wild-type and three neutrally marked wild-type (MWT) strains. As expected, the probability of winning was not statistically different among the different wild-type strains. (B) Competitions between wild-type and moderate mutators. (C) Competitions between a neutrally marked wild-type strain and moderate mutators. Mutator strains 2E2, 4A11, 4G4, and 9D2 were statistically more likely to win pairwise competitions than wild type.