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

Classification of aquatic organisms, Classification of Aquatic Organisms ...

Classification of Aquatic Organisms After discussing the common types of the aquatic ecosystem let us now study in brief the ecological classification of aquatic organisms. I

Regulation of cholesterol biosynthesis, Cholesterol can be gained either fr...

Cholesterol can be gained either from the diet or it can be synthesized de novo, mainly in the liver. Cholesterol is transported round the body in lipoprotein particles. The rate

What are the major characteristics of the bryophytes, Q. What are the major...

Q. What are the major characteristics of the bryophytes? Bryophytes are nonvascular plants that is they do not have conductive tissues and they perform transport of nutrients a

Why do sharks need to agitate their body to swim, Q. How different are the ...

Q. How different are the swimming strategies in chondrichthyes and in osteichthyes? Why do sharks need to agitate their body to swim while bony fishes do not? Bony fishes have

What are the major organic molecules for living beings, Q. What are the maj...

Q. What are the major significant organic molecules for living beings? There are many types of organic molecules that are important for the living beings. Particularly importan

Gregor johann mendel, GREGOR JOHANN MENDEL 1.         Mendel was born o...

GREGOR JOHANN MENDEL 1.         Mendel was born on 22 July 1822 at Heizendorf in Austria at Selesia village. 2.         Mendel was worked in Augustion Monastry as monk at Br

What is a graduated cylinder and how is it used, What is a graduated cylind...

What is a graduated cylinder and how is it used? A graduated cylinder is a piece of laboratory glassware used to accurately calculate out volumes of chemicals for use in reacti

Dna replication, DNA Replication Deoxyribonucleic acid (DNA) is the car...

DNA Replication Deoxyribonucleic acid (DNA) is the carrier of genetic data for all living creatures. An organism's genome, made of DNA, encodes the genetic blueprint for buildi

Examine six bad listening habits, Discuss six bad listening habits. Which d...

Discuss six bad listening habits. Which do you think is the biggest challenge for you personally?

Brucellosis, Br u c e ll osi s It is also called as Bang's diseas...

Br u c e ll osi s It is also called as Bang's disease or contagious abortion as it causes abortion in late pregnancy and infertility. E t iology: It is cause

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