Fig. 2.
The impact of purifying selection differs between genes with and without ASE in C. grandiflora. The estimated proportion of mutations in each bin of the distribution of negative fitness effects (DFE) is shown, with whiskers corresponding to 95% confidence intervals. The strength of purifying selection is given in units of the effective population size times the selection coefficient (Nes). Shown are the DFE for (A) nonsynonymous sites (zerofold degenerate sites), (B) introns, (C) promoter regions 500 bp upstream of the transcription start site, and (D) 3′-UTRs. Significance levels for comparisons of ASE and control genes are indicated by asterisks (*P ≤ 0.05; **P ≤ 0.01). These results are based on the population sample and the 1-epoch model.