Histone modifications mark dynamically regulated genes. In all panels, shades of green indicate active marks, whereas shades of pink represent repressive marks. The orange and yellow colors mark regions of 5 mC and 5 hmC, respectively. (A) The distribution of histone methylation and acetylation marks, along with the degree of methylation, is illustrated across the promoter region, TSS (transcriptional start site), and gene body of a transcriptionally active gene. (B) Histone H3 methylation and DNA methylation are found in the promoter region and surrounding the TSS in transcriptionally repressed genes. (C) Bivalent chromatin domains consist of discrete pockets of histone H3K4me3 within large regions of histone H3K27me3. DNA 5hmC is also found in bivalent domains.