Patent ID: 7238476

Claim:
A method of performing a primer extension reaction to identify variant nucleotides of target nucleic acids using chain terminators, comprising: obtaining an amplicon having a sequence generated from a target nucleic acid and a sequence generated from a first strand amplification primer, by amplifying a target nucleic acid having a nucleotide sequence containing a variant nucleotide flanked by an invariant nucleotide, wherein the first strand amplification primer employed to generate the sequence from the first strand amplification primer comprises a 5′ tag incapable of hybridizing to the target nucleic acid under amplification conditions, and wherein the 5′ tag contains the same nucleotide bases in sequence as the variant nucleotide and the invariant nucleotide of the target nucleic acid, employing the amplicon in a primer extension reaction wherein the identity of the variant nucleotide in the sequence generated from the target nucleic acid is determined by hybridizing a first identification primer immediately adjacent to the variant nucleotide in the sequence generated from the target nucleic acid; hybridizing a second identification primer immediately adjacent to the variant nucleotide in the sequence generated from the 5′ tag of the first strand amplification primer; extending the first and the second identification primers in the presence of two or more chain terminators and a polymerizing agent; and determining the identity of the variant nucleotide generated from the target nucleic acid by comparing extension product of the first identification primer and extension product of the second identification primer to identify the variant nucleotide of the target nucleic acid.