The attachment of a
methyl group (a -CH
3 group) to a
cytosine (one of four
nitrogenous bases found in DNA) in an
eukaryotic DNA mulecule. This is done routinely as a way to protect self DNA from the
enzymes and chemicals produced to destroy
foreign DNA and as a way to regulate
transcription of
genes in the DNA.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.