What is barr body genes, Biology

Assignment Help:

Q. What is Barr body Genes?

Located inside nuclear envelope, it's a densely staining object which is an inactivated X chromosome in female mammalian cells. Most Barr body genes aren't expressed. They are reactivated in gonadal cells that undergo meiosis to form gametes. Female mammals are a mosaic of two different types of cells, those with an active maternal X and those with an active paternal X. Which of the two Xs will be inactivated is concluded randomly in embryonic cells. After an X is inactivated, all mitotic descendants will have same inactive X. As a consequence, if a female is heterozygous for a sex-linked trait, about half of her cells will express one allele and the other cells well express alternate allele. Illustrations of this type of mosaicism are coloration in calico cats and normal sweat gland development in humans. A woman who is heterozygous for this trait has patches of skin and patches of skin lacking sweat glands. X chromosome inactivation is related with DNA methylation. Methyl groups (-CH3) attach to cytosine, one of DNA's nitrogenous bases. Barr bodies are highly methylated compared to actively transcribed DNA. What determines which of two X chromosomes would be methylated? - A newly discovered gene, XIST is active only on the Barr body. Product of the XIST gene, X-inactive specific transcript, is an RNA; multiple copies of XIST attach to X chromosome inactivating it.


Related Discussions:- What is barr body genes

Define the role of fluorine in human body, Define the role of Fluorine in H...

Define the role of Fluorine in Human Body? Fluorine is potentially a toxic element. Its essentiality for humans is not established although the role of fluoride in providing pr

Mineral availability of organic mineral complexes, Mineral availability of ...

Mineral availability of organic mineral complexes A number of mineral chelates and complexes are available from a variety of manufacturers. A chelate is described as a metal c

Class of coclentrata, ????? # 100 ??????????? #Minimum ?????? ?????

????? # 100 ??????????? #Minimum ?????? ?????

Explain phylum platyhelminthes, Phylum platyhelminthes (13,000 species Fla...

Phylum platyhelminthes (13,000 species Flatworm) The body is flattened. Gastrovascular cavity is branched, dense bodies with many cell layers, mouth but no anus. Hermaphrodite

Explain about insulin concentrations, Insulin Concentrations The doctor...

Insulin Concentrations The doctor always prescribes insulin dosage in units. Thus all types of insulin (crystalline, NPH, Lente, and so forth) is available in 10-ml vials that

What is revisions, Q. What is Revisions? Revision accounts for only a s...

Q. What is Revisions? Revision accounts for only a section of a genus or for the elements as restricted to a continent or smaller geographical area. Some revisions are based so

Explain the multiple organ dysfunction syndrome (mods), Explain the Multipl...

Explain the Multiple Organ Dysfunction Syndrome (MODS) Failure of essential organs is the most severe complication of sepsis and may result in death. The treatment of systemic

State the term cercaria, State the term Cercaria? A stage in the life c...

State the term Cercaria? A stage in the life cycle of trematode flukes. Cercaria develops from redia found in intermediate host. This tadpolelike organism is released from inte

What are zymogens, Zymogens, or proenzymes, are enzymes secreted in inactiv...

Zymogens, or proenzymes, are enzymes secreted in inactive form. Under certain conditions, a zymogen shifts to the active form of the enzyme. Zymogen secretions in general occur due

What is the general cognitive ability, What is the General Cognitive Abilit...

What is the General Cognitive Ability General cognitive ability is usually assessed using standardised intelligence tests, such as Wechsler Intelligence Scale for Children Thir

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd