Patent ID: 7846693

Claim:
A method for determining the methylation status of a potential methylation site in genomic nucleic acid comprising: treating genomic nucleic acid with an agent which modifies cytosine bases but does not modify 5-methyl-cytosine bases under conditions to form a modified nucleic acid template from two complementary strands of genomic nucleic acid containing a potential methylation site; providing a first clamp containing a first capture sequence and a second capture sequence, first capture sequence being complementary to a region flanking one side of the potential methylation site in the first strand of the modified nucleic acid template, and the second capture sequence being complementary to a region flanking one side of the potential methylation site in the second strand of the modified nucleic acid template; providing a second clamp containing a third capture sequence complementary to a region flanking the other side of the potential methylation site in the modified nucleic acid template; allowing the first clamp and the second clamp to hybridise to the modified nucleic acid template; ligating the hybridised first and second clamps to form a probe spanning the potential methylation site in the modified nucleic acid template; digesting the modified nucleic acid template to obtain the probe; and detecting the probe and determining the methylation status of the potential methylation site in the modified genomic nucleic acid.