Table 2 Summary of mutational effects for mutations evolved under growth selection
StrainFitnessEmbedded ImageEmbedded ImageEmbedded ImageEmbedded ImageEmbedded Image
ID8Embedded Image
AEmbedded Image3.59
BEmbedded Image5.98
CEmbedded Image5.85
DEmbedded Image6.54
EEmbedded Image6.40
ABEmbedded Image4.929.56Embedded Image.051.33Embedded Image.64
ACEmbedded Image4.699.44Embedded Image.161.10Embedded Image.74
ADEmbedded Image5.4810.13Embedded Image.061.89Embedded Image.65
AEEmbedded Image5.359.99Embedded Image.Embedded Image1.77Embedded Image.64
BCEmbedded Image4.4711.83Embedded Image.38Embedded Image.51Embedded Image.36
BDEmbedded Image3.0112.52Embedded Image.Embedded ImageEmbedded Image.Embedded ImageEmbedded Image.52
BEEmbedded ImageEmbedded Image.1512.38Embedded Image.Embedded ImageEmbedded Image.Embedded ImageEmbedded Image.53
CDEmbedded Image5.7212.39Embedded Image.82Embedded Image.13Embedded Image.67
CEEmbedded Image3.8712.25Embedded Image.Embedded ImageEmbedded Image.97Embedded Image.38
DEEmbedded Image3.7712.94Embedded Image.Embedded ImageEmbedded Image.Embedded ImageEmbedded Image.17
  • Fitnesses are given as the average ± SE over five replicate fitness assay measurements. Embedded Image denotes the fitness effect of the genotype relative to the wild-type (ID8). Embedded Image gives the expected fitness of a mutation pair under additivity. Embedded Image gives the effect of adding the first mutation in the double-mutant genotype name into the background of the second, and Embedded Image gives the effect of the second mutation in the background of the first. These are measurements of sign epistasis. Embedded Image denotes the deviation from additivity, as calculated by Equation 2 or by subtracting the value of Embedded Image from Embedded Image. A * denotes significant sign epistasis for Embedded Image or Embedded Image.