Bisulfite conversion

Bisulfite modification of DNA is the most commonly used, "gold standard" method for DNA methylation studies providing single nucleotide resolution. This technology is based on the chemical conversion of unmethylated cytosine to uracil. Methylated cytosines are protected from this conversion allowing to determine DNA methylation at the singe nucleotide level. Various analyses can be performed on the altered sequence to retrieve this information: bisulfite sequencing, pyrosequencing, methylation-specific PCR, high resolution melting curve analysis, microarray-based approaches, and next-generation sequencing.

How it works

Treatment of DNA with bisulfite converts cytosine residues to uracil, but leaves 5-methylcytosine residues unaffected (see Figures).