#heterochromatin
- Chromocenter — A microscopic nuclear structure formed by the fusion or aggregation of the pericentromeric heterochromatic regions (centromeres) of multiple chromosomes during cellular interphase. This dense structural formation, frequently observed within the salivary glands of certain insects (such as the polytene chromosomes of Drosophila), appears under the microscope as an intensely stainable central mass from which the euchromatic chromosomal arms radiate, lacking direct transcriptional activity in that zone.
- Allocyclies — An atypical mitotic or meiotic behavior of certain chromosomes or chromosomal segments (especially heterochromatin), structurally characterized by a desynchronized rhythm of condensation and replication compared to the rest of the chromosomal complement in the nucleus; it can be positive (precocious condensation) or negative (delayed condensation).