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chromatin |
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chromatin /chro·ma·tin/ (kro´mah-tin) the substance of chromosomes, the portion of the cell nucleus that stains with basic dyes. See euchromatin and heterochromatin. sex chromatin Barr body; the persistent mass of the inactivated X chromosome in cells of normal females.
chromatin [krō′mətin] Etymology: Gk, chroma, color the material within a cell nucleus from which the chromosomes are formed. It consists of fine, threadlike strands of DNA attached to proteins called histones and is readily stained with basic dyes. Chromatin occurs in two forms, euchromatin and heterochromatin, which are distinguishable during the phases of the cell cycle by their different degrees of staining, which in turn depends how tightly they are coiled. During cell division, portions of the chromatin condense and coil to form the chromosomes. Also called chromoplasm, karyotin. See also chromatid, euchromatin, heterochromatin, sex chromatin. chromatinic, adj. chromatin (krō´m n the genetic material present in the nucleus, consisting of DNA and associated proteins, seen as irregular clumps in quiescent cells. chromatin the substance of the chromosomes, composed of nucleic acids and basic proteins (histones), the material in the nucleus that stains with basic dyes. sex chromatin Barr body; the persistent mass of the material of the inactivated X chromosome in cells of normal females. See also drumstick. chromatin Genetics The stainable material of interphase nuclei corresponding to chromosomes; chromatin consists of nucleic acids–DNA and associated histone protein, which are packed into nucleosomes; euchromatin is loosely packed and
accessible to RNA polymerases. See Salt & pepper chromatin. Cf Heterochromatin. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
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This modification alters chromatin structure to influence gene expression. The scientists next disrupted the chromatin structure, dissociating the DNA from the histone H1. This technique is important, as changes in chromatin structure play an important role in the silencing of certain genes in cancer, and histone deacetylase inhibitors have demonstrated anti-cancer effect. |
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