Heterochromatin is a tightly packed form of DNA. Its major characteristic is that transcription is limited. As such, it is a means to control gene expression, through regulation of the transcription initiation.
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heterochromatin
highly condensed chromatin that stains deeply; thought to be genetically inert
Source: Jenkins, John B. 1990. Human Genetics, 2nd Edition. New York: Harper & Row ...
Heterochromatin, other than centromeric heterochromatin, dispersed throughout eukaryotic chromosomes.
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Heterochromatin Chromatin which is condensed in interphase and which replicates later than the rest of the genome.
Heterochromatin. Dark-stained regions of chromosomes thought to be for the most part genetically inactive.
Heteroduplex. A double-stranded DNA molecule or DNA-RNA hybrid, where each strand is of a different origin.
Heterochromatin and Euchromatin
Heterochromatin is tightly wound DNA and visible during interphase. It is inactive because DNA cannot be transcribed while it is tightly wound.
Euchromatin is not tightly wound. It is active.
Heterochromatin
The term proposed by Heitz (1928) for parts of chromosomes with an abnormal degree of contraction or of staining properties at nuclear divisions (Gk. heteros, different). Composed of repetitive DNA, stains dark bands in G-banding.
Heterochromatin properties are mediated by proteins specifically associated with satDNAs that, however, are poorly characterized.
Heterochromatin stains more strongly and is a more condensed chromatin. Euchromatin stains weakly and is more open (less condensed). Euchromatin remains dispersed (uncondensed) during Interphase, when RNA transcription occurs.
heterochromatin Chromatin that stains intensely and appears to represent inactive genetic areas.
heterochrony Evolutionary change in the relative time of appearance or rate of development of characteristics from ancestor to descendant.
Heterochromatin HeterodimerComplex of two different proteins. Heteroduplex DNA Heteroplasmy HeterotrophicRequiring a supply of organic compounds (food) from the environment.
The predominant type of chromatin found in cells during interphase, euchromatin is more diffuse than the other kind of chromatin, which is termed heterochromatin.
The centromeric DNA is normally in a heterochromatin state, which is probably essential for its function. In this chromatin, the normal histone H3 is replaced with CENP-A, a centromere-specific variant.
It exists in two forms: less dense euchromatin can be transcribed, and heterochromatin is highly condensed and cannot be transcribed. Inactive X chromosome of female mammals is an example of heterochromatin.
active genes in euchromatin, and inactive genes in heterochromatin
B.
amplification of some genes such as rRNA genes ...
 See also: Chromatin, Chromosome, DNA, Chromosomes, Protein
  
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