Figure 8.

Least-squares fits to the distribution of fitness effect. (a) Cumulative distribution of beneficial effects of mutations in fitness. (b) Cumulative distribution of deleterious effects of mutations in fitness. In both cases, solid circles represent the numerical results of the simulations (see main text for details). Different functions fitting the data are shown, as specified in the legend. The insert shows the distribution of small effects (up to a 25% change in fitness), which is well fit by a Pareto distribution. The mutation rate is in both cases μ = 0.004.