A model of temporal patterns of chromatin state changes during differentiation. (A) Increased gene expression level is associated with enhanced enrichment in chromatin states (color bars). Promoter regions (P) are particularly prone to modifications. G, gene body; E, enhancer. (B) Patterns of chromatin state dynamics during adipogenic differentiation. A blank state is commonly temporally followed by loading of chromatin states (color bars). States can then be replaced by another (substitution), become a site of emergence of one or more other states (insertion), or may shift in position (shift).