Figure 9.

Combined effect of the amount and speed of change. Each cell in each plot shows the frequency of +/+ cells or the average fitness of the population (its growth rate) after T_i generations per cell, as a function of h₁ (the threshold before the treatment) and h₂ (the threshold after the treatment), for s = 20 and c = 0.01. T₁=T₃ = 1000; before T₁ h₂=h_1. A therapy that increases the threshold is effective only when the initial threshold is low, the new threshold is high enough and the shift to the new threshold is fast enough.