Patent ID: 8163485

Claim:
A method of detecting the quantity of methylation at a locus within a population of nucleic acids, the method comprising (a) dividing the population of nucleic acids into at least two physically distinct portions, thereby generating at least a first portion and a second portion, (b) after step (a), contacting the first portion with a methylation-sensitive restriction enzyme to obtain a first portion of nucleic acids with fragmented unmethylated copies of the locus and intact methylated copies of the locus; (c) after step (b), quantifying the number of intact copies of the locus in the first portion; (d) after step (a), contacting the second portion with a methylation-dependent restriction enzyme to obtain a second portion of nucleic acids with fragmented methylated copies of the locus and intact unmethylated copies of the locus, wherein the methylation-dependent restriction enzyme is contacted to the second portion under conditions that allow for at least some copies of potential restriction enzyme cleavage sites for the methylation-dependent restriction enzyme in the locus to remain uncleaved; (e) after step (d), quantifying the number of intact copies of the locus in the second portion; and (f) determining the quantity of methylation at the locus within the population of nucleic acids by comparing the number of intact copies of the locus in the first portion and number of intact copies of the locus in the second portion.