Quantitative relationships between active (K4me3) and repressive (K27me3) chromatin marks on the same promoter.

Input-normalized densities of K4me3 and K27me3 in TSS-proximal regions of individual autosomal genes are shown in a two-dimensional scatter plot in log-log space, with color (black to red) representing levels of gene expression (silent to strongly active) measured by FPKM values based on RNA-Seq. Three major regions of the plot correspond to distinct levels and correlation patterns of K4me3 and K27me3. These regions largely correspond to silent (region 1), bivalent (region 2) and active genes (region 3).