Comparison of hypomethylated regions (HMRs) in fibroblasts and keratinocytes. (a) Venn diagram showing overlapping fibroblast (91X) and keratinocyte (36X) HMRs. Big color pie charts show genomic localization (five groups) of tissue-specific and common HMRs. The common HMRs are enriched in the promoter region (red). Small black-white pie charts show the composition of CG methylation. Low-methylated CGs (10% to 50% methylated, in gray) are enriched in tissue-specific HMRs while unmethylated CGs (<10% methylated, in white) are enriched in common HMRs. (b) Overlap between keratinocytes (Ker) and fibroblast (Fb) HMRs. The percent of the genome represented for two tissue-specific (S1) and eight groups of overlapping HMRs (C1-C5) are shown. Pie charts show fraction of HMRs in five genomic regions. (c) Length comparison between keratinocytes and fibroblasts HMRs. For the tissue-specific HMRs (S1, blue for Fb, and red for Ker), the length of HMRs in the other cell is 0. (d) Heat map of CG methylation for the tissue-specific and common HMRs along with two published methylomes for embryonic stem (ES) and neuronal progenitor (NP) cells . The common HMRs are unmethylated (red) in all four methylomes. Fibroblast and keratinocyte specific differentially methylated regions (S1) are more methylated than the common HMRs (C1). Keratinocyte specific HMRs in fibroblasts show intermediate methylation compared to neighboring sequences and vice-versa.