Fig. 2.
The relative rate of X versus autosome adaptive substitution when a proportion of substitutions are drawn from standing genetic variation. Results are based on equations (4), (7), and (9), with (KA/Kx)new = 4E(h)/[1 + 2E(h)], p = 0.1, and E[s/sd] = 0.1. Given the parameters, the corresponding total probabilities of adaptation using standing genetic variation are as follows: Pr(SGV) = 0.038 for Nevn = 0.1; Pr(SGV) = 0.177 for Nevn = 0.5; and Pr(SGV) = 0.323 for Nevn = 1. For Nevn → 0, KA/Kx = 4E(h)/[1 + 2E(h)], which corresponds to the high-n/low-Nevn result under SSWM conditions and parallels the result of Charlesworth et al. (1987).