Comparison of STR Genotyping of Two Whole Genome Amplification Methods for Minute DNA

Abstract

Objective To apply multiple displacement amplification (MDA)to improve primer extension preamplification (IPEP) for whole genome amplification (WGA) and to compare their effects on forensic DNA analysis. Methods DNA samples of varying amounts were for WGA based on MDA and IPEP.WGA products yield was evaluated by real-time quantitative PCR and STR genotyping performance was determined with AmpFLSTR? Identifiler(R) Kit. Results The DNA quantity was increased about 103～106 folds by MDA and 25～310 folds by IPEP. The least genome DNA amount is 1ng for MDA and 0.05ng for IPEP to obtain accurate genotypes of all loci. IPEP products and MDA products of 0.01 ng～0.1 ng DNA exhibited more loci observed than original DNA that was not for WGA,and IPEP products exhibited more loci observed than MDA products. Conclusion Both MDA and IPEP can improve STR genotyping of forensic minute DNA. The yield of MDA is higher than IPEP but the sensitivity of IPEP is higher than MDA and the STR genotyping effect of IPEP products is better than MDA products so IPEP is better for forensic trace DNA analysis. Key words: Multiple displacement amplification; Improved primer extension preamplification; Whole genome amplification; STR genotyping