Chromatin signatures of different classes of genes. (A) Enrichment of specific chromatin marks or combination of marks (including DNA methylation) in expressed, activated, and occluded genes. Asterisks indicate that activatable and occluded genes are statistically different for a mark or combination of marks, with P-values calculated by two-tailed Fisher's exact test. (B) Occluded genes tend to have larger enrichment peaks than activatable genes for H3K9me3 and H3K27me3. (C) Expressed genes have a more average number of predicted active enhancers than silent genes. (D) More occluded than activatable genes correspond to genes possessing bivalent promoters in ESCs (Bernstein et al. 2006).
