Multiplex genotyping and allele frequency estimation in pooled DNAs using non-gel capillary electrophoresis

We present a novel approach of single-nucleotide polymorphism (SNP) analysis in which allele-specific oligonucleotide hybridization is followed by non-gel capillary electrophoresis (ASOH-NGCE) in conjunction with laser-induced fluorescence (LIF). This allows rapid multiplex allelotyping and allele frequency estimation. This method, based on site separation of the hybridization duplexes, retains the simplicity and specificity of ASOH and the homogeneous feature of NGCE with poly(N,N-dimethylacrylamide) (PDMA) as a sieving medium. ASOH-NGCE can be applied to multiplex SNP loci genotyping with excellent separation of hybridization mixtures. Average relative standard deviations (RSDs) were low for within-day (1.10%) and between-day (2.41%) reproducibility. Moreover, the allele frequencies in pooled DNAs were accurately determined from peak areas and equilibrium dissociation constants. Our method was highly sensitive in detecting alleles with frequency as low as 1% and in distinguishing allele frequencies differing by 1% between pools. The average value of differences between real and estimated frequencies (accuracy) was only 0.004.