Figure 2.

The maximal change of the variance with time (+), i.e. ${\max }_{t,i}d{{\Pi }_0}_{\mathit{ii}}^{\mathit{zz}}(t,t)∕\mathit{dt}$ where Π₀^zz is obtained from Eqs. 27 and 28, depends on the mutation rate as an inverse power law. Shown are calculations for a nonepistatic version of the landscape as described in section 4 with a) two possible mutations — r₀ = 0, Δr₁ ≈ 0.049, Δr₂ ≈ 0.010, b) three possible mutations — r₀ = 0, Δr₁ ≈ 0.049, Δr₂ ≈ 0.010, Δr₃ ≈ 0.002 — and c) four possible mutations — r₀ = 0, Δr₁ ≈ 0.049, Δr₂ ≈ 0.020, Δr₃ ≈ 0.006, Δr₄ ≈ 0.002. In this case, the fitness of each state is simply the sum of contribution from each mutation. The solid lines indicate power law fits using the values for μ ≤ 10⁻⁵. Their exponents are a) −1.999, b) −2.989, and c) −3.939. The exponent is observed to be equal to the number of mutational steps in the landscape.