Evolutionary footprint of epistasis
Fig 1
Positive epistasis enhances adaptation.
Wright-Fisher population of 500 genomes has been simulated for 20 generations, starting from uniformly wild-type (best-fit at E = 0) population. The adaptation rate A = dW/dt (bottom row) and substitution rate Vs0 = s0 df/dt (upper row) were averaged over 300 runs and are plotted as a function of the epistatic strength, E. The selection coefficient s0 and E are the same for all sites. Parameters in (a-h): |s0| = 0.2, total site number L = 300, mutation rate per genome μL is shown (colors). The binary connectivity matrix Tij is random with ~1 interaction per site. Each column corresponds to a different sign of s0 and E (shown). (a, d, e, h) In the two cases of reciprocal epistasis, the evolution rates demonstrate strong non-linear dependence on the epistatic strength.