Patent ID: 8148064

Claim:
A method for detecting the extension of a primer annealed to a target polynucleotide, comprising: (a) providing at least one nucleoside comprising (1) a label attached via a first linker to the nucleoside base, and (2) a protecting group attached via a second linker to the 2′ or 3′ oxygen of the nucleoside sugar, wherein the first and second linkers are both cleavable under a single set of conditions; (b) extending the annealed primer with the nucleoside only if the nucleoside base is complementary to the base at the corresponding position of the target polynucleotide; (c) detecting the presence of the label on the extended primer; and (d) incubating the extended primer under the single set of cleavage conditions, whereby both the first and second linkers are cleaved; thereby detecting the extension of the primer.