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Heterochromatin

Heterochromatin

(Science: cell biology, genetics) The chromosomal regions that are condensed during interphase and at the time of nuclear Division.

They show what is considered an abnormal pattern of staining as opposed to euchromatin. Can be subdivided into constitutive regions (present in all cells) and facultative heterochromatin (present in some cells only). The inactive x chromosome of female mammals is an example of facultative heterochromatin.


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Re: Difference between chromatid and chromatin?

... In mitosis (and meiosis), general transcription is shut down, DNA associates with proteins tightly, becomes a very dense structure called heterochromatin. Chromosomes are now visible under light microsope. Note, that chromosomes are now visible as duplicates, so we actually call each chromosome ...

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by kk
Sat Jan 17, 2009 1:55 pm
 
Forum: Cell Biology
Topic: Difference between chromatid and chromatin?
Replies: 3
Views: 3180

homologous sex chromosomes

... say that they have big homologous regions. I'm not sure how pertinent your analogy is, but if you are referring to differences in euchromatin and heterochromatin, I don't believe that is known. BTW, if that's what you wanted to know, you might have just asked. However, if crossing over occurs(which ...

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by Aggie2
Thu Aug 23, 2007 12:09 am
 
Forum: Genetics
Topic: homologous sex chromosomes
Replies: 5
Views: 824

Replies

... use their careers for. One thing I can say: a chromosome has a linear amount of DNA (a sequence of genes) that can be silenced (turned into heterochromatin) or activated (turned into euchromatin) in different ways, at different times. So, its the different interactions that take place within ...

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by rui_benfeitas
Sat Feb 17, 2007 1:24 pm
 
Forum: Molecular Biology
Topic: Protein-biomolecules
Replies: 4
Views: 1508

The Fiber Disease

... maize genome (2). In Drosophila, ˜10–15% of the genome is estimated to be made up of TEs, most of which are found in distinct regions of centric heterochromatin (3). TEs are classified in families according to their sequence similarity. Two major classes are distinguished by their differing modes ...

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by codon blue
Tue Nov 14, 2006 8:04 pm
 
Forum: Human Biology
Topic: The Fiber Disease
Replies: 7403
Views: 748648

i need an illustration

... The red can represent the maternal, and the blue paternal, or vice versa. Now for the phases: G1 - no chromosomes are formed, only uncondensed heterochromatin exist, which cannot be seen by the naked eye. In contrast, constitutive chromatin cannot decondense, so these regions are visible; however, ...

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by majik1213
Fri Jun 30, 2006 4:39 pm
 
Forum: Cell Biology
Topic: i need an illustration
Replies: 1
Views: 671
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