Figure 4
From: Duplication and selection in the evolution of primate β-defensin genes
The rates of synonymous and nonsynonymous substitutions within first and second exons. Graphs of the number of synonymous substitutions per synonymous site (dS) against the number of nonsynonymous substitutions per nonsynonymous site (dN) for comparisons between (a) the first exons and (b) second exons of all genes in the dataset. In each case the diagonal line represents dN = dS.