The present invention provides a method of identifying a base at a target position in a single-stranded sample DNA sequence wherein an extension primer, which hybridizes to the sample DNA immediately adjacent to the target position, is provided and the sample DNA and extension primer are subjected to a polymerization reaction in the presence of a deoxynucleotide or dideoxynucleotide, whereby the deoxynucleotide or dideoxynucleotide will only become incorporated and release pyrophosphate if it is complementary to the base in the target position. Release of pyrophosphate is detected enzymatically and pyrophosphate detection enzyme(s) are included in the polymerization step.
EP 0932700-B1 (2001-08-29); JP 3510272-B2 (2004-03-22)