Patent ID: 7452671

Claim:
A method for reducing the complexity of a genomic DNA sample comprising: (a) fragmenting the sample with a restriction enzyme that has a recognition sequence that comprises at least one variable position, wherein the at least one variable position is in the single-stranded overhang generated by cleavage with the restriction enzyme and cleavage generates a plurality of overhangs of different sequence wherein the plurality of different overhangs consists of a first, a second, a third and a fourth overhang that vary at a single position of the overhang; (b) ligating selective adaptors to the fragments to generate adaptor-ligated fragments, wherein a first, a second, a third and a fourth selective adaptor perfectly complementary to the first, second, third and fourth overhangs, respectively, are ligated to the fragments; and (c) amplifying at least some of the adaptor-ligated fragments by polymerase chain reaction using a primer complementary to the selective adaptor.