heterochromatin


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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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

het·er·o·chro·ma·tin

(het'ĕr-ō-krō'mă-tin),
The part of the chromonema that remains tightly coiled and condensed during interphase and thus stains readily.
Synonym(s): heteropyknotic chromatin
Farlex Partner Medical Dictionary © Farlex 2012

heterochromatin

(hĕt′ə-rō-krō′mə-tĭn)
n.
Tightly coiled chromosomal material that stains deeply during interphase and is believed to be genetically inactive.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

het·er·o·chro·ma·tin

(het'ĕr-ō-krō'mă-tin)
The part of the chromonema that remains tightly coiled and condensed during interphase and thus stains readily.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

heterochromatin

A length of chromatin in the genome that is permanently highly condensed and whose DNA is not transcribed.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

heterochromatin

any chromosomal segments or whole chromosomes that appear darkly stained during interphase of the CELL CYCLE (as compared to EUCHROMATIN) due to tight condensation, which may indicate genetic inactivity. Hetero chromatin may be condensed at all times (constitutive) or only at certain times (facultative). see C-BANDING.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
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References in periodicals archive ?
Indeed, long CTG-repetitions were shown to induce heterochromatin formation, which can then spread into neighbouring regions [22].
Transcriptionally repressive chromatin remodelling and CpG methylation in the presence of expanded CTG-repeats at the DM1 locus
Adams, "Molecular dissection of formation of senescence-associated heterochromatin foci," Molecular and Cellular Biology, vol.
Cell senescence in myxoid/round cell liposarcoma
The karyotype of specimens from the central population, Iraquara (MN 68092 and MN 68094) and distribution of constitutive heterochromatin (C-banding; Fig.
Diferenciacao cromossomica em Kerodon rupestris (Rodentia: Caviidae) da regiao semiarida brasileira
TFL2/LHP1, the plant homologue of animal HP1, surprisingly does not primarily localize to heterochromatin but it participates in the regulation of specific genes in euchromatic regions.
Histones and plant hormones: new evidence for an interesting interplay
The structure of a nucleus of this participant at an early stage of reprogramming (mainly heterochromatin and lack of a nucleolus) convinces us that it is an oligodendrocyte.
Increased cell fusion in cerebral cortex may contribute to poststroke regeneration
The analysis of the C-banding pattern revealed large blocks of constitutive heterochromatin located on the pericentromeric regions of all chromosomes (Figure 2), and the first pair presented a completely heterochromatic long arm.
Description of the karyotype of Geophagus cf. proximus (Perciformes, Cichlidae, Geophaginae)/Descricao do cariotipo de Geophagus cf. proximus (Perciformes, Cichlidae, Geophaginae)
C., 1971.--Distribution of constitutive heterochromatin in mammalian chromosomes Chromosoma (Berl.).
Caracterizacion cariologica de tres monos Aotus griseimembra (Primates: Aotidae) mantenidos en cautiverio
These characteristics have been frequently related to the presence of large terminal heterochromatin blocks on the rye chromosomes (Thomas & Kaltsikes, 1974; Merker, 1976; Bennett, 1977; Roupakias & Kaltsikes, 1977; Gustafson & Bennet, 1982; Naranjo & Lacadena, 1982; Soler et al., 1990; Jouve & Soler, 1996) .
Telomeric heterochromatin, seeds and meiotic characteristics in two tricepiro lines/Heterocromatina telomerica, semillas y caracteristicas meioticas en dos lineas de tricepiro
Earlier research had suggested that in the absence of stress, ATF-2 plays a role in silencing certain genes through the formation of heterochromatin, a tightly-packed variety of chromatin whose state is epigenetically heritable.
RIKEN: Mechanism for Stress-induced Epigenetic Inheritance Uncovered in New Study
Jmjd2b antagonizes H3K9 tri-methylation at pericentric heterochromatin in mammalian cells.
Epigenetic alterations in liver of C57BL/6J mice after short-term inhalational exposure to 1,3-butadiene

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