The PinPoint Assay

Single base extension methods such as the PinPoint assay have an advantage for multiplexed SNP marker analysis. Notably, they can combine aU assays irrespective of the alleles to be genotyped simply by using the four dideoxynucleotides 

A simple way to avoid ambiguities related to the inconvenient mass difference between pinpoint products is the use of mass-modified terminator nucleotides, as introduced by Smith and coworkers (153). The rationale design of terminator nucleotides with a perfect mass separation can be achieved by selecting appropriate mass-modifying chemical moieties. 

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