A rapid one-tube PCR method for simultaneously differentiating homozygotes and heterozygotes of the Sp1 binding site polymorphism in collagen type Ialpha1

Rapid detection of single-base changes is fundamental to molecular medicine. PCR amplification of specific alleles (PASA) has previously been used as a rapid method of genotyping single-nucleotide changes, but one reaction is required for each allele. This paper describes a Bidirectional PASA (Bi-PASA) method, which was developed to distinguish between homozygotes and heterozygotes in one PCR reaction. The method is tested using the Sp1 polymorphism in Collagen type Ialpha1. The results demonstrate that Bi-PASA is a simple and rapid method for detecting the zygosity of the polymorphism in a single PCR reaction.