Table 4 Summary of mutational effects for mutations evolved under pH-shock selection
StrainGrowth rate (γ)Embedded ImageEmbedded ImageEmbedded ImageEmbedded ImageEmbedded ImageDecay rate (δ)Embedded ImageEmbedded ImageEmbedded ImageEmbedded ImageEmbedded ImageOverall fitness (w)Embedded ImageEmbedded ImageEmbedded ImageEmbedded ImageEmbedded Image
ID8Embedded ImageEmbedded ImageEmbedded Image
KEmbedded Image4.35Embedded ImageEmbedded Image.94Embedded Image3.56
LEmbedded Image3.54Embedded Image7.13Embedded Image3.90
MEmbedded Image2.77Embedded Image8.56Embedded Image3.20
NEmbedded Image4.31Embedded ImageEmbedded Image.86Embedded Image4.21
OEmbedded Image4.54Embedded ImageEmbedded Image.29Embedded Image4.38
KLEmbedded Image2.437.89Embedded Image.11Embedded Image.Embedded ImageEmbedded Image.46Embedded Image31.40Embedded Image.8124.2747.3440.22Embedded Image4.007.450.100.44Embedded Image.45
KMEmbedded Image3.607.130.83Embedded Image.75Embedded Image.53Embedded Image4.92Embedded Image.38Embedded Image.6420.8612.30Embedded Image3.856.760.650.29Embedded Image.91
KNEmbedded Image5.188.660.870.82Embedded Image.48Embedded ImageEmbedded Image.39Embedded Image.80Embedded Image.5411.5513.41Embedded Image4.967.770.741.40Embedded Image.81
KOEmbedded Image4.088.90Embedded Image.47Embedded Image.28Embedded Image.82Embedded Image2.28Embedded Image.245.5718.2221.51Embedded Image4.197.93Embedded Image.190.63Embedded Image.74
LMEmbedded Image3.046.310.27Embedded Image.50Embedded Image.27Embedded Image28.0915.6919.5320.9612.40Embedded Image4.447.101.240.55Embedded Image.65
LNEmbedded Image3.127.85Embedded Image.18Embedded Image.41Embedded Image.72Embedded ImageEmbedded Image.845.271.02Embedded Image.97Embedded Image.11Embedded Image3.088.11Embedded Image.13Embedded Image.81Embedded Image.03
LOEmbedded Image2.998.08Embedded Image.Embedded ImageEmbedded Image.55Embedded Image.09Embedded ImageEmbedded Image.833.83Embedded Image.53Embedded Image.96Embedded Image.66Embedded Image1.358.27Embedded Image.Embedded ImageEmbedded Image.Embedded ImageEmbedded Image.92
MNEmbedded ImageEmbedded Image.927.08Embedded Image.Embedded ImageEmbedded Image.Embedded ImageEmbedded Image.00Embedded Image6.106.717.95Embedded Image.47Embedded Image.61Embedded ImageEmbedded Image.617.41Embedded Image.Embedded ImageEmbedded Image.Embedded ImageEmbedded Image.03
MOEmbedded Image2.427.31Embedded Image.Embedded ImageEmbedded Image.35Embedded Image.89Embedded Image11.345.2714.632.776.07Embedded Image2.997.58Embedded Image.38Embedded Image.21Embedded Image.58
NOEmbedded Image3.668.85Embedded Image.88Embedded Image.65Embedded Image.19Embedded ImageEmbedded Image.96Embedded Image.15Embedded Image.67Embedded Image.11Embedded Image.81Embedded Image2.468.59Embedded Image.92Embedded Image.75Embedded Image.13
  • γ, δ, and w are given as the average plus or minus the standard error over five replicate fitness assay measurements. Embedded Image, Embedded Image, and Embedded Image denote the fitness effect of the genotype relative to the wild-type (ID8). Embedded Image, Embedded Image, and Embedded Image give the expected fitness of a mutation pair under additivity. Embedded Image, Embedded Image, and Embedded Image give the effect of adding the first mutation in the double-mutant genotype name into the background of the second, and Embedded Image, Embedded Image, and Embedded Image give the effect of the second mutation in the background of the first. These are measurements of sign epistasis. Embedded Image, Embedded Image, and Embedded Image denote the deviation from additivity, as calculated by Equation 2 or by subtracting the value of Embedded Image, Embedded Image, or Embedded Image from Embedded Image, Embedded Image, or Embedded Image. A * for each double-mutant denotes significant sign epistasis for the effects of each single mutation in the background containing the second single mutation.