CpG islands are regions of DNA near the
promoter of a
eukaryotic gene where a large concentration of
CpG sites exist. Unlike CpG sites in the
coding region of a gene, the CpG sites in the CpG islands are un-methylated. This raises the possibility that methylation of CpG may inhibit the
expression of a gene but altering the promoter.
All Wikipedia text
is available under the
terms of the GNU Free Documentation License