Figure 2. The impact of purifying selection differs between genes with and without ASE in C. grandiflora. The estimated proportion of mutations in each Nes bin of the distribution of negative fitness effects (DFE) is shown, with whiskers corresponding to 95% confidence intervals. The panels show the DFE for nonsynonymous sites (0-fold degenerate sites) (A), for introns (B), for promoter regions 500 bp upstream of the transcription start site (C) and for 3'-UTRs (D). Significance levels for comparisons of ASE and control genes, that were also amenable to analysis of ASE, are indicated by asterisks (*: P-value ≤ 0.05, ** P-value ≤ 0.01). These results are based on the population sample and the one-epoch model.