Objective: To develop a multiplex allele-specific PCR (AS-PCR) assay with three-color fluorescence labeling for mitochondrial DNA (mtDNA) SNP typing.
Methods: Based on the principle of AS-PCR, the primer sets were designed for 20 SNP located on the coding region of mtDNA and divided into 2 groups labeled with FAM and HEX fluorescence, respectively. A primer set included two forward (reverse) allelic specific primers with different sizes and a generic reverse (forward) primer. Blood samples from 200 unrelated individuals were analyzed by AS-PCR and capillary electrophoresis. Three random samples at least for each SNP site were examined and verified by direct sequencing. The haplotype frequency was investigated.
Results: Distinct electropherograms of 200 blood samples were obtained successfully. The typing results of direct sequencing were identical to those obtained from AS-PCR. The minimum detectable DNA concentration was 0.2 pg under the system of 10 microL. The sensitivity of the DNA concentrations ranged from 0.5 to 5 pg. The 200 individuals were assigned into 15 haplotype, and the haplotype diversity was 0.906 0.
Conclusion: AS-PCR is a simple, rapid and efficient method for mtDNA SNP typing, and can be applied to forensic practice.