Figure 4.

Top panel: Conditional mean fixation time ${\overline{T}}_c$ for a mutant under strong positive selection at all times with selection coefficient $s(t)=\overline{s}+\sigma \hspace{0.17em}\text{sin}(\omega t+\theta )$ when the mutant is beneficial at all times to show that, except for strongly recessive or dominant mutations, it depends weakly on the dominance coefficient h. The points are obtained by numerically calculating (18) for dominance coefficient $h=0.1(♦),0.3(\ast ),0.5(■),0.7(○),0.9(•)$ in a population of size N. The other parameters are $N={10}^5,\overline{s}=0.01,\sigma =0.007,\theta =\pi /4$. The bottom panel shows the comparison between (18) (points) and (20) (line) for the deviation in the conditional mean fixation time in a slowly changing environment where $\omega \ll s(0)\approx 0.014$.