Best Answer

The Lyon hypothesis states that in cells with multiple X chromosomes, all but one is inactivated during mammalian embryogenesis. X-inactivation leads to clumped chromatin termed Barr bodies, which are generally considered inert. This formation of Barr bodies is called Lyonization. In humans the X chromosome that is inactivated is determined by chance. In marsupials, however, the paternal X chromosome is always inactivated. Inactivation is achieved by methylation of the X chromosome DNA, a common way in which the cell silences particular genes. Certain animals have their coloring patters dictated by this phenomenon. For example, female Calico cats have unique patterns of fur due to certain areas where different X chromosomes are inactived. The X chromosomes that are activated express different coloring genes and lead to their mosaic fur color. However, there are now reports that women still express many genes from their inactive X chromosomes, and that different women express different genes from the inactive X. Research by Carrel and Willard (2005) indicates that 15% of the genes on the inactive X chromosome are actually active across all women, and a further 10% of genes were switched on in some women. The hypothesis was first stated by Mary F. lyon in 1961 while she was studying the genetic consequences of radiation exposure, and therefore bears her name.

User Avatar

Wiki User

14y ago
This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: What is the mechanism of Lyonization and example of organism that under go it?
Write your answer...
Still have questions?
magnify glass
Related questions

How is oxytocin an example of a hormone that is under positive regulaton?

Yes it is an example. There a positive feed back mechanism take place

The burrow a chipmunk digs under a patio stone is an example of an?

it could be the habitat (the place in which an organism lives)... that is a guess so don't get mad at me if it isn't ;)

How does an organism's niche differ from its habitat?

Niche: an organism's role in the environment. Habitat: specifically where it lives. For example, many organisms maybe have the same habitat (under a log, if we're considering insects), but as long as they occupy different niches, they will not be in competition.

Where unicellular organism is seen?

Under microscopes

What organism is found under a stone?

bacteria :)

What organism can flatten its backbone to get under a door?


How do you change a fuel pump on a 2001 Mazda Protege?

release gas pressure, get to the pump mechanism under the back seat, replace the pump in the mechanism

Do amoebas poop?

Actually, yes they do! Any living organism, including one celled organisms, have a mechanism for getting rid of waste. If you look at a living amoeba under a microscope, every now and then you can see it leave a small particle of waste behind. This is amoeba poop!

Your outside door handle mechanism has snapped is this under warranty?

Check with the dealership.

What is organisim?

An organism is a living thing. It can be a micro-organism, which can only be seen under a microscope, a fungus, a plant or an animal.

An individual organism?

Species (under the Biological Species Concept).

How do you open a 1987 Sonoma with a slim Jim?

the lock mechanism is in the rear, right under the lock, all you do is take the slim Jim and push the mechanism down and forward.