Figure 6.

The distribution of the roughness to slope ratio and the fraction of sign epistasis over 1000 genotypic fitness landscapes generated with 5 mutations. Top left panel: distribution of roughness to slope ratio when W₀₀ = 0.1, for three levels of complexity, for independently selected mutations (distributions for co-selected mutations are very similar). In these conditions, there is no sign epistasis in more than 95% of the landscapes. Top right panel: distribution of the statistics in independently selected (blue) vs. co-selected mutations (purple). Bottom panel: distribution of the statistics for different levels of complexity (n = 3, n = 10, n = 100 in blue, red, green) in independently selected mutations (left) and co-selected mutations (right). Statistics corresponding to three experimental landscapes are superimposed (C: Chou et al. 2011, K: Khan et al. 2011, W: Weinreich et al. 2006).