Pairwise comparisons of evolutionary rates for toxins and nontoxins. The histograms show the distributions of the (A) ratio of pairwise nonsynonymous to synonymous substitution rates (d N/d S), the (B) pairwise nonsynonymous substitution rates (dN), and the (C) pairwise synonymous substitution rates (dS) for the nontoxins. The vertical dashed lines represent the 95th percentile of the nontoxin values. The values for the toxin are shown as a rug plot, with values above the 95th percentile for the nontoxins indicated by gray triangles. P-values were based on Wilcoxon rank sum tests. Abbreviations: 3FTx–three-finger toxin, AChE–acetylcholinesterase, CTL–C-type lectin, CRISP–cysteine-rich secretory protein, KUN-Kunitz-type protease inhibitor, SVMP–snake venom metalloproteinase.