Patent ID: 8192961

Claim:
A method for identifying a nucleotide in a template nucleic acid sequence, said method comprising: a) providing a complex of a polymerase, a template nucleic acid sequence and a primer sequence, wherein said polymerase or said template nucleic acid sequence is immobilized on a solid support, b) contacting said complex with one or more types of optically labeled nucleotides, wherein the one of said one or more types of optically labeled nucleotides are unblocked at the 3′OH and each of the one or more types of optically labeled nucleotides comprises a base and a γ-phosphate having an optical label; c) producing an extended primer by incorporation of the bases of the one or more optically labeled nucleotides in a primer extension reaction and detecting said incorporation by cleaving said γ-phosphate from each of one or more nucleotides whose base or bases is/are incorporated into said extended primer and detecting an optical signal produced by said optical label on said γ-phosphate; and d) identifying the nucleotide in said template nucleic acid sequence.