Figure 2.—

Influence of effective population size on (a) genetic variance, (b) the mean–optimum deviation, and (c) the linear selection gradient. Results are given for two models: stabilizing selection with mutation effects normally distributed with mean equal to the bias, as assumed by Waxman and Peck (2003) (diamonds), and joint pleiotropic and stabilizing selection with positive and negative mutation effects on the trait gamma distributed with τ_a = 0.1 and the bias dependent on the proportion decreasing the trait and with pleiotropic effects on fitness following an independent exponential distribution with mean E(s) = 0.05 (squares). The mutational bias on the trait is Δ = −0.04σ_E for the pure stabilizing selection model and Δ = −0.02σ_E (the probability of decreasing mutants P = 0.753) for the joint-effect model.