Fig. 7
From: Adaptive evolution in the toxicity of a spider’s venom enzymes
a Statistical analysis of SMase D classes for sum of sites under positive selection. The absolute frequency of summed amino acids is indicated for Classes I and II. Nonpolar, basic polar, neutral polar and acidic polar amino acids are indicated. The p-values obtained by the Wilcoxon test and t test are shown. b Distribution of nonpolar + basic and neutral and acidic residues in Class I and Class II members