Summary: DNA methylation is an epigenetic event that affects
cell function by altering gene expression and refers to the
covalent addition of a methyl group, catalyzed by DNA
methyltransferase (DNMT), to the 5-carbon of cytosine in a CpG
dinucleotide. Methods for DNA methylation analysis can be
divided roughly into two types: global and gene-specific
methylation analysis. For global methylation analysis, there are
methods which measure the overall level of methyl cytosines in
genome such as chromatographic methods and methyl accepting
capacity assay. For gene-specific methylation analysis, a large
number of techniques have been developed. Most early studies
used methylation sensitive restriction enzymes to digest DNA
followed by Southern detection or PCR amplification. Recently,
bisulfite reaction based methods have become very popular such
as methylation specific PCR (MSP), bisulfite genomic sequencing
PCR. Additionally, in order to identify unknown methylation hot-
spots or methylated CpG islands in the geno