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

Isolate genomic dna, You may have heard in the news currently that a new sp...

You may have heard in the news currently that a new species of frog was discovered within a rainforest. You objective are to isolate genomic DNA and construct an expression libr

Different blood groups in man, Different blood groups in man 1.Blood Gr...

Different blood groups in man 1.Blood Group "A": Persons having this blood group will have antigen "A' on their red blood cells and antibody "B" in their plasma. 2. Blood Gr

Kreb cycle, where does kreb cycle takes place

where does kreb cycle takes place

What are the hormones produced by the testicles, What are the hormones prod...

What are the hormones produced by the testicles and the ovaries? The testicles make androgenic hormones, the major of them being testosterone. The ovaries make estrogen and pro

Portal hypertension, Portal Hypertension: If you review the portal cir...

Portal Hypertension: If you review the portal circulation you may recall that normal blood flow to and from the liver depends on proper functioning of  the portal vein, the he

What happens to pepsin when it passes into the duodenum, Q. Since pepsin is...

Q. Since pepsin is a gastric enzyme does it have a basic or an acid optimum pH? What happens to pepsin when it passes into the duodenum? Pepsin acts contained by the stomach so

Issues to be discussed while counselling a diabetic patient, Q. Issues to b...

Q. Issues to be discussed while counselling a diabetic patient ? Issues to be discussed · Counselling at Diagnosis · Diabetes is Controllable · Counselling for Day

Explain the working of conical flasks, Explain the working of Conical Flask...

Explain the working of Conical Flasks? Conical flasks of different volumes can be used for media preparation and also for culturing large amount of microorganisms in liquid med

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