Epigenetic and accessibility profiles reflect different modes of transcriptional control of genes within the H3K4me2 clusters. (A) H3K4me1 average profiles. (B) The number of DHSS in regions from TSS to 8 kb downstream is shown. (C) Comparison between the frequency of DHSS in genes within cluster 1 and that observed for all genes expressed at the same level. (D) Distribution of DHSS locations with respect to the TSS for each H3K4me2 cluster.