Fig. 2

Enhancers with distinct densities of deMPs in HepG2 cell line have different functional constraints. a Distribution of densities of deMPs in HepG2 enhancers. The top, middle, and bottom 20% of enhancers correspond to fragile, regular, and stable enhancers, respectively. b deMPs are under strong purifying selection compared to enhancer regions. The y-axis shows the fraction of alignable nucleotides different from the chimp genome. The dashed line labels the expected fraction of alignable nucleotide different from the chimp genome using pseudogenes as the background. c More orthologous sequences of stable enhancers in the mouse genome have H3K27ac peaks than those of fragile enhancers. The p value was calculated based on Fisher’s exact test. d Larger fraction of stable enhancers located within phastCon conserved elements compared to fragile enhancers. p values were calculated using the Mann–Whitney–Wilcoxon test