Figure 1

One example of distribution of mutation effects. (A) The effects of deleterious mutations follow a gamma distribution with α = 0.6 (shape parameter), β = 0.5 (scale parameter) and the mean effects is ${\overline{s}}_d=0.3$. (B) The effects of beneficial mutations follow an exponential distribution with λ = 100 and the mean effects is ${\overline{s}}_b=0.01$. (C) The distribution of fitness changes by both deleterious and beneficial mutations with p _d = 97% and p _b = 3%.