FIG. 3.

Head-to-head competition results. The selection rate constant between each pairwise competition, ±2 standard errors, is listed on the bracket connecting two strains. Displayed values have been increased ×100. Each box represents a strain within the set. The outcomes within the four sets of competitions are internally consistent. (A) Endpoint strain competition outcomes. The results of pairwise competitions are on the left and combined in the diagram on the right with the measured selection rates displayed on the connecting brackets. The increased strain fitness correlates roughly to a higher measured growth rate. The mutations acquired by each endpoint strain are listed in Fig. 1B. (B) Outcome of competitions between allele replacement strains harboring one of the identified rpoB/C mutations. Mutations are described by the abbreviations shown in Fig. 1B, which reference the source endpoint strain and the gene affected. (C) Outcome of glpK allele replacement strain competitions. (D) Competitions between double allele replacement strains that carry both the glpK and the rpoB/C mutations identified in the same endpoint strain. The asterisk indicates that the value does not agree well with estimates extrapolated from the rest of the set and may represent systematic measurement error (see Discussion).