Summary of chromatin patterns observed in Drosophila heterochromatin. The predominant enrichment patterns observed for selected histone modifications and proteins are summarized for active and silent genes and intergenic regions, in euchromatin, pericentric heterochromatin (including the S2-specific extensions), and the 4th chromosome. Red, “silent” marks and proteins; green, “active” marks. Heights of color blocks within each row indicate enrichment levels relative to the features shown below, whose combinatorial patterns are reflected in the colors and intensities. For example, the lighter red used for intergenic regions and silent genes in chromosome 4 indicate lower enrichments for “silent” marks compared with pericentric heterochromatin. Gradients across active genes reflect differences in the relative levels of “active” and “silent” marks; red, predominantly “silent” marks; green, predominantly “active” marks; yellow, enrichments for both. Silent genes in euchromatin are shown in gray to indicate the absence of “silent” marks.
