Figure 1.

The mean (blue dashed curve) and median (red solid curve) of allele frequency trajectories for $\alpha =0.8,1,1.5,2,$ and 2.5. For each α, 10⁴ trajectories are generated with the initial frequency $x_0=0.01$. For ease of viewing, only 50 trajectories are shown in gray in each panel. The time t in units of generations and the one $\tau =\frac{t}{T_c}$ re-scaled by the coalescent timescale T_c are shown in the horizontal axes. The dependence of the coalescent time on the population size N is written below each panel. The population size is $N={10}^5$.