Fig. 3.

âPositive selection on repressor alleles is enhanced by increasing costs of hybrid dysgenesis. Evolution of (A) mean diploid TE copy number (n) and (B) maternal repression (R) over 500 generations of simulated evolution. The thick line represents the average response across all replicate populations. (C) The site frequency spectra of occupied small-RNA-producing sites after 500 generations of simulated evolution. The spectra were calculated by pooling the data from all replicate simulated populations. Site frequency bins include sites whose frequencies are higher than the lower bound, and less than or equal to the upper bound. (D) The average number of occupied small-RNA (colored) and pseudo-small-RNA (gray) sites in each replicate simulated population after 500 generations. A site is considered occupied if it carries a TE insertion in at least one individual in a population. Population sizes were Nâ=â2,000 for all simulations, and individuals had a baseline transposition rate of $Î=0.1$, an empirically estimated fitness model (Ï_e), and experienced no ectopic recombination $(E_0=0)$. Colors indicate simulations with different values for maximum hybrid dysgenesis (D). For Dâ=â0.5, blue indicates only simulated populations that exhibited successful invasion while purple indicates all simulated populations.