heterochromatin /het·ero·chro·ma·tin/ (-kro´mah-tin) that state of chromatin in which it is dark-staining, genetically inactive, and tightly coiled.
heterochromatin
heterochromatin [het″er-o-kro´mah-tin]
het·er·o·chro·ma·tin (h t  -r -kr m-t n)n. The part of the chromonema that remains tightly coiled and condensed during interphase and thus stains readily. |
heterochromatin
[-krō′mətin]
Etymology: Gk, heteros, different, chroma, color
the part of a chromosome that is inactive in gene expression but may function in controlling metabolic activities, transcription, and cell division. It stains most intensely during interphase and usually remains in a condensed state throughout the cell cycle. It consists of two types: constitutive heterochromatin, which is present in all cells and is characteristic of the Y chromosome, and facultative heterochromatin, which is present in the inactivated X chromosome of the mammalian female. Compare euchromatin. See also chromatin. heterochromatic, adj.
heterochromatin [het″er-o-kro´mah-tin]
that state of chromatin in which it is dark-staining, genetically inactive, and tightly coiled.
constitutive heterochromatin the chromatin in regions of the chromosomes that are invariably heterochromatic; it contains highly repetitive sequences of DNA that are genetically inactive and serves as a structural element of the chromosome.
facultative heterochromatin the chromatin in regions of the chromosomes that become heterochromatic in certain cells and tissues; for example, it makes up the inactive X chromosome in female somatic cells.
heterochromatin
that state of chromatin in which it is dark-staining, genetically inactive, and tightly coiled.
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