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

Which does not contain a guanidinium group, Which of the following does NOT...

Which of the following does NOT contain a guanidinium group Select one: a. Urea b. arginine c. creatine d. guanidinium ion

Is the embryonic development in birds indirect or direct, Q. Is the embryon...

Q. Is the embryonic development in birds indirect or direct? The embryonic development is direct there is no larval stage. Q. What are the predominating chemical compounds

Which are plant tissues that form the plant roots, Which are plant tissues ...

Which are plant tissues that form the plant roots? Roots have a central portion called medulla made of vascular tissue outer phloem and inner xylem. Medulla is delimited by per

Explain energy requirement during tuberculosis, Explain Energy requirement ...

Explain Energy requirement during tuberculosis Energy  :  The criteria to establish  the energy intake is the body weight status coupled with the rise  in body temperature. Con

Method of cloning dna fragments into plasmids, During our discussion of rep...

During our discussion of replication origins we took a step-by-step look at the method of cloning DNA fragments into plasmids . Based on your knowledge of this discussion which

Explain coarctation of aorta, Explain Coarctation of Aorta ? Coarctati...

Explain Coarctation of Aorta ? Coarctation of aorta may be isolated or it may have other co-existing cardiac and vascular lesions. In critically ill neonates with coarctation,

Production diseases, Pr o d u c t i o n Diseases The production...

Pr o d u c t i o n Diseases The production diseases, which were previously referred as metabolic diseases, include diseases like parturient paresis (milk fever), downer

Explain class bivalvia in animal kingdom, Explain Class Bivalvia in animal ...

Explain Class Bivalvia in animal kingdom? This name of this Class reflects the group's most distinguishing feature. Clams, oysters, scallops and mussels all have two shells tha

Classification of drugs, CLASSIFICATION OF GENERAL DRUGS - 1 .       ...

CLASSIFICATION OF GENERAL DRUGS - 1 .       NATURAL DRUGS - Obtained from natural sources as minerals, animals, plants & microorganism. (i)       Minerals - It include

Which statement about asexual reproduction is false, Which statement below ...

Which statement below about asexual reproduction is FALSE? a.With asexual reproduction, offspring are genetically identical to the parent. b.Asexual reproduction requires no

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