Properties of the reference landscape.

<p>(A) Number of different optima attained from steepest-ascent hill-climbing walks starting from random genotypes plotted as a function of the number of starting genotypes. (B) Distribution of attraction domains of steepest-ascent hill-climbing walks: Starting genotypes are chosen in the neighborhoods of 500 randomly chosen reference genotypes. Of each reference genotype, 100 random single, double, triple, fourfold, and fivefold mutants are considered as starting genotypes. Each dot corresponds to a local optimum. Coordinates indicate from how many unique neighborhoods (y-axis) and from what fraction of starting-genotypes in these neighborhoods the optimum is reached (x axis). Thus the y- and x-axis correspond to the global and local density of the attraction domain respectively. (C) Autocorrelation of log-fitness along random walks as a function of the number of steps. The red line corresponds to the linear least square fit of the autocorrelation and the correlation length is given by −1/(slope of the line). (D) Range explored by quasi-neutral walks for different discrete values of the maximal fitness-effect <i>ε</i> which quasi-neutral mutations are allowed to have. Points correspond to the mean over 10⁵ walks of length 1000. 95%-confidence-intervals of the mean (inferred through 1000 bootstrap samples) are smaller than point size.