Patent ID: 7771973

Claim:
A method for determining the sequence of a target single-stranded polynucleotide, comprising monitoring the sequential incorporation of complementary nucleotides, wherein at least one incorporation is of a nucleotide having a removable 3′-OH blocking group covalently attached thereto, such that the 3′ carbon atom has attached a group of the structure —O—Z wherein Z is any of allyl, —C(R′) 2 —N 3 , —C(R IV ) 2 —O—R″, —C(R′) 2 —N(R″) 2 , —C(R′) 2 —N(H)R″, or —C(R IV ) 2 —S—R″, wherein —C(R IV ) 2 —O—R″ is of the formula —CR 4 (R 5 )—O—CR 4 (R 5 )—OR 6 or of the formula —CR 4 (R 5 )—O—CR 4 (R 5 )—SR 6 ; and wherein —C(R IV ) 2 —S—R″ is of the formula —CR 4 (R 5 )—S—CR 4 (R 5 )—OR 6 or of the formula —CR 4 (R 5 )—S—CR 4 (R 5 )—SR 6 ; each R″ is or is part of a removable protecting group; each R′ is independently a hydrogen atom, an alkyl, substituted alkyl, arylalkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocyclic, acyl, cyano, alkoxy, aryloxy, heteroaryloxy or amido group, or a detectable label attached through a linking group; or (R′) 2 represents an alkylidene group of formula ═C(R′″) 2 wherein each R′″ may be the same or different and is selected from the group comprising hydrogen and halogen atoms and alkyl groups; each R 4 and R 5 is independently a hydrogen atom or an alkyl group; and R 6 is alkyl, cycloalkyl, alkenyl, cycloalkenyl or benzyl, and wherein the blocking group is removed prior to introduction of the next complementary nucleotide.