Definition of Dna Methylation

DNA methylation is a process through which the structure of the DNA is modified as a methyl group comes, gets attached to it and renders changes in the genes’ functions and also affects the expression of these genes. DNA methylation comes under the category of epigenetic modification.


Example of DNA Methylation:

The nitrogenous base which gets methylated the most is cytosine. The methyl group attacks on the fifth carbon of cytosine and this results in forming 5-methylcytosine. Consequently, the process of transcription is inhibited as this methyl becomes part of the major groove of the DNA molecule. The genomic DNA of a human has 1.5% of this 5-methylcytosine and due to this fact, it is also known to be the fifth base of DNA.  


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