Patent ID: 7312054

Claim:
A method for increasing the selectivity or fidelity of extension of a nucleic acid sample by polymerase enzymes utilizing a primer where the 3′ end of a primer does not hybridize perfectly with the target, wherein the primer is i) an added primer or ii) a growing nucleic acid chain that is being polymerized, the growing nucleic acid chain acting as a primer for the addition of the next nucleotide of the sequence, the method comprising the steps of: a) obtaining a nucleic acid sample; b) hybridizing the nucleic acid sample to a primer; c) providing a reaction extension mixture comprising a polymerizing enzyme and an ethidium bromide present in an amount of from about 4 to about 7 μg/ml; d) subjecting the hybridized nucleic acid sample to an extension reaction by extending the primer with a polymerizing enzyme, and blocking the primer in the extension reaction of step c) by polymerizing enzymes where the 3′ end of a primer does not hybridize perfectly with the target, thereby increasing the selectivity of single nucleotide mutation or gene analyses by suppressing false positive results, and e) detecting the presence of extension products or amplified products.