TABLE 2

Fitness gain by the original ϕ6

Bottleneck sizeFitness gaina ± SEM
100.063 ± 0.047
33-0.062 ± 0.084
100 0.064 ± 0.053
333-0.043 ± 0.116
1000 0.134 ± 0.048*
  • a Gain estimated as log10 (WA) - log10(WB), where WA and WB are, respectively, fitness of the original ϕ6 clone after and before selection. The phage were selected for the same number of generations as the corresponding recovery population (Figure 3) at each ofthe bottleneck sizes. Fitness was measured (three replicates) by our standard assay and relative to the marked reference ϕ6 clone, but whereas fitness before selection was that of the original f6 clone, fitness after selection was measured for the population. Population fitness was used to make the fitness gain here comparable to Table 1. Asterisks indicate a fitness gain significantly greater than zero (nA = nB = 3, *P < 0.05 by a t-test; Sokal and Rohlf 1994).