Correlation of genetic and epigenetic characteristics at coding region boundaries. (a) Bending propensity and CpG density were calculated for flanking sequences downstream of the start codon or upstream of the stop codon. The number of genes (gray curve measured on the right scale), methylation level (red curve), and nucleosome level (blue curve) were obtained according to the bendability (upper panels) and CpG density (lower panels) near the start codon (left panels) and stop codon (right panels). (b) A total of 25,883 genes were clustered by the strength of the marks near their coding ends. Marks with strengths higher than the median level of all genes were considered significant.