Patent ID: 7160680

Claim:
A method for mass-spectrometric analysis of a known mutation site in genome DNA, the method comprising: providing an extension primer having a nucleotide chain that contains a photocleavable linker and attaching the primer to the DNA adjacent to the mutation site; extending the primer using mutation dependent primer extension with a complementary mixture of non-terminating and terminating nucleoside triphosphate derivatives, said mixture having a ratio of one non-terminating to three terminating nucleoside triphosphate derivatives, or two non-terminating to two terminating nucleoside triphosphate derivatives, the terminating nucleoside triphosphate derivatives terminating the extension at one of a plurality of predetermined lengths; cleaving the photocleavable linker with UV light irradiation to produce a DNA cleavage product; and analyzing the DNA cleavage product using mass spectrometric analysis to determine the nucleotide present at the mutation site.