Homogeneous Real-Time Detection of Single-Nucleotide Polymorphisms by Strand Displacement Amplification on the BD ProbeTec ET System

Abstract

Abstract Background: The BD ProbeTec™ ET System is based on isothermal strand displacement amplification (SDA) of target nucleic acid coupled with homogeneous real-time detection using fluorescent probes. We have developed a novel, rapid method using this platform that incorporates a universal detection format for identification of single-nucleotide polymorphisms (SNPs) and other genotypic variations. Method: The system uses a common pair of fluorescent Detector Probes in conjunction with unlabeled allele-specific Adapter Primers and a universal buffer chemistry to permit analysis of multiple SNP loci under generic assay conditions. We used Detector Probes labeled with different dyes to facilitate differentiation of two alternative alleles in a single reaction with no postamplification manipulation. We analyzed six SNPs within the human β2-adrenergic receptor (β2AR) gene, using whole blood, buccal swabs, and urine samples, and compared results with those obtained by DNA sequencing. Results: Unprocessed whole blood was successfully genotyped with as little as 0.1–1 μL of sample per reaction. All six β2AR assays were able to accommodate ≥20 μL of unprocessed whole blood. For the 14 individuals tested, genotypes determined with the six β2AR assays agreed with DNA sequencing results. Conclusion: SDA-based allelic differentiation on the BD ProbeTec ET System can detect SNPs rapidly, using whole blood, buccal swabs, or urine.