4) In heterochromatin, histones are hypo-acetylated: Histones may undergo post-translational modifications of their N-terminal ends which may affect the genetic activity of the chromatin. It appears darker under the microscope. There are many chromatin modifications that can be used to identify heterochromatin function. The heterochromatin regions are not present in the prokaryotic genome or are comparatively less. It is located around the centromere and usually contains repetitive sequences. Dark-stained regions of chromosomes thought to be for the most part genetically inactive. It persists throughout the cycle. HP1 and the dynamics of heterochromatin maintenance. Heterochromatin Definition. facultative heterochromatin: [ het″er-o-kro´mah-tin ] that state of chromatin in which it is dark-staining, genetically inactive, and tightly coiled. Euchromatin is the loosely packed DNA found in the inner body of nucleus and consists of transcriptionally active regions of DNA while heterochromatin is the tightly packed DNA discovered in the periphery of nucleus and consists of transcriptionally inactive DNA regions in the genome. Therefore, it is a permanent factor for a particular type of cells. Chromatin is the structure that holds the DNA strand of a chromosome. As stated above, the condensed state for structural heterochromatin is a constant phenomenon, as opposed to an optional one. Both play a role in the expression of genes. They are the tightly packed form of DNA in the nucleus. Generally, this type of heterochromatin is made up of highly repetitive DNA. inner body of the nucleus. CallUrl('en>wikipedia>orgmacroevolution>nethtml',0), ~TildeLink() 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 has condensed chromatin structure and is inactive for transcription, while euchromatin has loose chromatin structure and active for transcription. Euchromatin is defined as the area of the chromosome which is rich in gene concentration and actively participates in the transcription process. The structure of Heterochromatin is easily explained by analysing the ‘Constitutive Heterochromatin’ and ‘Facultative Heterochromatin’. Heterochromatic definition, of, having, or pertaining to more than one color. Its most notable property is its ability to silence euchromatic gene expression. Structural heterochromatin is a structure formed by a highly coiled state. 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