This method utilized methylation-sensitive restriction enzymes to digest DNA, cleaving at specific sites, which have been altered by DNA methylation, followed by Southern blot analysis of the DNA products. A very simple technique to analyze DNA methylation, however, it is very prone to numerous downfalls: poor sensitivity; very large amounts of DNA are required in order to receive a signal on blotting, and is only to detect methylated CpG’s that are recognized by the enzymes. Overall, there is little control of the sites/outcome of the test by the researcher, and a great deal of work and time must be spent in obtaining large amounts of DNA, and of good quality. Not recommended for any clinical samples/materials, such as biopsies and paraffin-embedded tissues because of this.
J.P.Issa, et al. Methylation of the oestrogen receptor CpG island links ageing and neoplasia in human colon. Nat. Genet. (1994) 7: 536-540.