When would DNA Methylation be used?

[thank.darwin]

When would this process be used? For what purpose? And briefly explain how it happens...

[DevGrp]

Just thrown down some ideas, sorry its abit random


DNA methylation appears to have at least two roles.

Human DNA is heavily and specifically methylated. This methylation protects the DNA from nucleases which are on the lookout for foreign invading DNA (Viral?) which will have different / no methylation and is thus attacked by the nucleases.

Methyaltion may also be a way of controlling gene expression. Methylated genes seems to be less expressed than non-methylated ones. The pattern of methylation is a very important step in the development of embryos. Maternal and paternal DNA is methylated to different degrees and this controls gene expression involved in development.
As you can see this may cause problems for cloned organisms where the neuclei come from adult cells with adult methyaltion patterns.

methylation may also have a role in cancer protecting chromosome ends in highly deviding cells.

Methylation also causes problems in molecular biology as some restriction enzymes don't work if their recognition site is methylated.

A good description of DNA methylation is given at:

http://www.muhlberg.edu/depts/chemistry ... /mbdna.htm

[thank.darwin]

Thank-you DevGrp for the information - It helped a lot