Figure 5: Analyses of nucleotide diversity.
(a) Rank-ordered distribution of Fay and Wu’s H values across large protein families. Horizontal lines indicate 95% bootstrap confidence intervals. Negative values indicate an increase in the abundance of high-frequency-derived mutations, which are signals of selective sweeps. Additional coalescent simulations were carried out to test the significance of individual genes (Supplementary Data 3). (b) Fay and Wu’s H values estimated for functional groupings within chemosensory families. Horizontal lines indicate 95% bootstrap confidence intervals. Numbers along the right margin indicate the number of genes included in the analyses, with the asterisk indicating significantly negative H (95% confidence interval excludes 0). (c) Box plots contrasting the ratio of replacement diversity to silent diversity (a population-level measure of functional constraint) among the chemosensory families and the pooled non-chemosensory protein families. Significant heterogeneity exists among PR/PS values (P values<<0.01; Kruskal–Wallis test). The only pair-wise comparisons remaining significant after correcting for multiple tests are the chemosensory versus large family comparisons (Wilcoxon signed-rank tests P values<0.005).
