Tissue type is a major modifier of 5hmC levels in genes. (A) Unsupervised hierarchical clustering of 12 loci by absolute 5hmC levels results in two groups containing high (HIGH) and low (LOW) levels of 5hmC, respectively, for each indicated tissue. (Red boxes) H19/IGF2 loci; (blue boxes) HOXA loci. (B) Box-plot of 5hmC (%) levels of all five loci in the HIGH cluster for each tissue shows that the range of 5hmC levels at HIGH loci varies markedly between tissues. (C) The relative global 5hmC content (Fig. 1C) correlates with average 5hmC (%) content of each tissue as determined by 5hmC-qPCR. (D) Inter-tissue differences in 5hmC levels do not correlate with inter-tissue expression levels. Average 5hmC (%) content of genic loci of H19 (upper panel) and IGF2 (lower panel) in each indicated tissue is plotted against expression of probes (H19 = 1 probe; IGF2 = 2 probes) for each gene obtained from the GNF expression database. The GNF expression database does not contain data for breast.
