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

Nutrition support for myocardial infarction, Q. Nutrition Support for myoca...

Q. Nutrition Support for myocardial infarction patient? The nutrient requirements of a MI patient vary from time of getting hospitalized in an emergency to the time of getting

What are the plant tropisms, What are the plant tropisms? Tropisms are ...

What are the plant tropisms? Tropisms are the movements that caused by external stimulus. In Botany the studied plant tropisms are phototropism (tropism in response to light),

Cerebral palsy, Cerebral Palsy Cerebral palsy is a non-progressive neu...

Cerebral Palsy Cerebral palsy is a non-progressive neuromuscular disorder characterised by disorder of strength, muscle control, posture or movement due to brain injury, befor

Explain 3rd type of hypersensitivity, It is immune difficult mediated hype...

It is immune difficult mediated hypersensitivity. Typical manifestations contain rheumatoid arthritis, serum sickness, necrotizing etc.

Is herbivorism a form of predatism, Is herbivorism a form of predatism? ...

Is herbivorism a form of predatism? Herbivorism is a type of predatism in which first order consumers feed from producers (plants or algae). For instance, birds and fruits, hum

Electrophoresis, Electrophoresis is the technique of separating the large ...

Electrophoresis is the technique of separating the large molecules (for instance DNA fragments or proteins) from the mixture of identical molecules. An electric current is passed

What are the main cellular features of fungi, What are the main cellular fe...

What are the main cellular features of fungi? There are unicellular and pluricellular fungi. All fungi are eukaryotes and heterotrophs. Fungi have cells with cell wall made

Explain corrective surgery - endodontic surgery, Explain Corrective Surgery...

Explain Corrective Surgery - Endodontic Surgery perforation repair periodontal management (root resection, tooth resection) intentional reimplantation

Artificial inspiration, Artificial Inspiration : a. After artificial exp...

Artificial Inspiration : a. After artificial expiration, the rescue worker should slowly release the pressure on the back of the victim. b. This will cause the chest cavity t

Characteristics of female''s skeleton, CHARACTERISTICS OF FEMALE'S SKELETON...

CHARACTERISTICS OF FEMALE'S SKELETON - 1.      Skull is lighter. 2.      Shoulders are nanow. 3.      Sacrum is shorter but wider. 4.      Pelvis is wider. 5.

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