- Heterochromatin that is fixed and irreversible. Regions of constituitive heterochromatin are located at very specific spots in the genome (on chromosomes 1, 9, 16 and the Y chromosome, the tiny short arms of chromosomes 13-15 and 21 and 22, and near the centromeres of chromosomes) and consists of DNA that contains many tandem (not inverted) repeats of a short basic repeating unit (known as satellite DNA).
Medical dictionary. 2011.
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Heterochromatin — A genetically inactive part of the genome, heterochromatin was so named because it was chromosomal material (chromatin) that stained differently, more darkly, all through the cell cycle, than most chromosomal material (which was named… … Medical dictionary
Constitutive heterochromatin — domains are sections of DNA that occur throughout the chromosomes of eukaryotes, but particularly at the centromeres and telomeres. They often consist of very highly condensed, repetitive DNA and are largely transcriptionally silent. These… … Wikipedia