Preferential methylation of PcG targets. The difference between average β-values for AML minus the average β-values in normal CD34+, CMP, and GMP progenitors is defined as Δβ. (A) Δβ for PcG-targeted genes; overall and for CpG residues within and outside CpG islands. (B) Venn diagram showing the overlap of PcG targets, bivalently marked genes, and DMC 1 + DMC 2 in relation to all measured CpG sites. The OR for overlap between PcG targets and DMC 1 + DMC 2 is 2.8 (P < 1 × 10−20) and for bivalently marked genes and DMC1 + DMC 2 is 4.4 (P < 1 × 10−20). (C) Δβ for genes with bivalent chromatin marks; overall and for CpG residues within and outside CpG islands. (D) Δβ for genes both bivalently marked and PcG-targeted (middle, dark blue, n = 694), PcG-targeted only (left, light green, n = 1662), and bivalently marked only (right, light blue, n = 1180). Error bars represent 95% CI.
