Figure 5. A significant relationship between changes in promoter methylation and protein evolution between human and chimpanzee.

We performed a comparison of alterations in promoter methylation with (A) the frequency of amino-acid alterations and (B) the relative rate of coding to non-coding variation with genes (K_A/K_I) between human and chimpanzee. Using both metrics we observed a significant association between the rate of protein evolution and epigenetic regulatory changes. P-values are based on 1,000 permutations (Differentially methylated genes, n = 745; genes without significant changes in methylation, n = 6,507).