Table 3 Fitnesses and fitness effects of all genotypes tested at 37°
GenotypeFitnessnΔWwtΔWaddΔW1ΔW2εij
ID1115.18 ± 0.2014
A19.07 ± 0.1953.89
B19.34 ± 0.4354.15
C19.36 ± 0.5664.18
D18.62 ± 0.4973.44
E16.84 ± 0.3651.65
F18.58 ± 0.3753.39
G21.02 ± 0.2665.84
H18.62 ± 0.4253.44
I16.60 ± 0.2851.42
AB18.66 ± 0.2553.478.04−0.68−0.42−4.57
AD18.82 ± 0.3753.637.330.19−0.26−3.69
AF18.07 ± 0.5652.887.28−0.51−1.01−4.40
AG22.50 ± 0.2557.329.731.483.43−2.41
AH20.29 ± 0.2955.107.331.661.21−2.23
BD17.77 ± 0.3352.597.59−0.85−1.56−5.00
BE15.58 ± 0.5360.405.81−1.25−3.75−5.41
BG17.31 ± 0.5472.129.99−3.72−2.03−7.87
BH19.47 ± 0.4354.297.590.850.14−3.30
BI16.52 ± 0.4871.345.57−0.08−2.81−4.23
CD17.52 ± 0.3662.347.62−1.10−1.84−5.28
CE11.56 ± 0.476−3.625.83−5.27−7.80−9.46
CH19.49 ± 0.2854.317.620.870.13−3.31
DF19.30 ± 0.3154.126.830.730.68−2.72
DH18.48 ± 0.4353.306.88−0.14−0.14−3.58
DI15.40 ± 0.3450.214.86−1.21−3.23−4.64
EH16.54 ± 0.4451.355.10−2.09−0.30−3.74
EI12.74 ± 0.355−2.443.07−3.86−4.09−5.51
  • Fitnesses are given as the average plus or minus the standard error. n gives the number of replicate assays for each genotype. The fitness effect relative to the wild type is designated by ΔWwt. ΔWadd gives the fitness effect expected on the assumption that the effects of single mutations were additive, ΔW1 gives the effect of adding the first mutation in the genotype name into the background of the second, and ΔW2 gives the effect of adding the second mutation in the genotype name into the background of the first. The deviation from additivity, εij for the combination of mutations i and j, was calculated according to Equation 2.