Table 1.
Main features associated to the different chromatin domains in higher eukaryotes
| Feature | Euchromatin | Heterochromatin |
|---|---|---|
| Structure | Loosely packed, open, accessible | Densely packed, closed, inaccessible |
| Composition | Mainly genes | Mainly repetitive elements |
| Activity | Expressed, active | Repressed, silent |
| DNA methylation | Hypomethylation | Hypermethylation |
| Histone post-translational modifications | Hyperacetylation of H3 and H4, H3K4me1, H3K4me2, H3K4me3, H3K27me3 | Hypoacetylation of H3 and H4 H3K9me2 |
| Histone variants | H2AX, H2A.Z | H2A.Z, CENH3 (CENP-A) |