Genomic distribution of DNA methylation in granulopoietic cells. (A) A schematic picture of hematopoiesis showing the position of CMP, GMP, PMC, and PMN cell populations with regard to other hematopoietic cells. Dashed lines represent existence of intermediate populations. (B) Frequency plots showing the distribution of β-values in CGIs, shores (0-2 kb flanking islands), shelves (2-4 kb flanking islands), and open sea (unrelated to islands). DNA methylation was measured with the IlluminaHumanMetylome 450 Beadchip using biological triplicate samples for CMP, GMP, PMC, and PMN cells. Completely unmethylated CpG: β = 0; completely methylated CpG: β = 1.