Patent ID: 6610486
Filing Date: 2003-08-26
Classification: C12Q

Abstract:
A method of detecting a nucleotide variation within a first nucleic acid, comprising:a) generating a set of single-stranded extension products from the first nucleic acid in the presence of modified nucleotide bases, wherein the extension products incorporate modified nucleotides and thereby limit exonuclease activity to the 3â€²-terminal nucleotide base, and wherein the extension products have variable lengths; b) hybridizing the variable length extension products to a reference nucleic acid; c) contacting the hybridizing nucleic acids with a first enzyme which can remove the 3â€²-terminal nucleotide of the extension products, and with a second enzyme which extends those extension products that can be further extended in the presence of selected labeled nucleotides, wherein extension products that terminate with a 3â€²-nucleotide that does not hybridize with the corresponding position on the reference nucleic acid are replaced with a nucleotide that hybridizes with the corresponding nucleotide on the reference nucleic acid and wherein those extension products that had a non-hybridizing nucleotide at the 3â€²-terminus can now be distinguished from those extension products that had a hybridizing nucleotide at the 3â€²-terminus; and d) distinguishing those extension products that had a non-hybridizing nucleotide at their 3â€²-terminus from those extension products that had a hybridizing nucleotide at their 3â€²-terminus, thereby detecting nucleotide variation in the first nucleic acid.