Figure 4

Distribution of non-synonymous to synonymous (dN/dS) substitution rates for domains of different age combined in the same protein. dN/dS values were calculated in the domains found in 330 human and mouse 1:1 orthologous proteins. Differences in dN/dS between Old and Vertebrate domains were highly statistically significant (Wilcoxon test, p < 10^-5).