两种全基因组扩增方法用于微量检材STR基因座分型比较

目的 应用多重置换扩增(MDA)技术和改进型扩增前引物延伸（IPEP）技术对法医学微量DNA进行全基因组扩增，比较两种方法的STR分型效果及法医学应用价值。 方法 用MDA、IPEP方法分别对不同模板量DNA进行扩增，扩增产物用实时荧光定量PCR技术定量、用AmpFLSTR® Identifiler®试剂盒检测基因型。 结果 MDA方法可对模板DNA增加103～106倍，IPEP方法可增加25～310倍。为获得完整准确的分型结果，MDA最低需1ng基因组DNA，IPEP最低需0.05ng基因组DNA。当基因组DNA为0.01ng～0.1ng时，IPEP产物、MDA产物的平均基因座检出数均高于未经全基因组扩增的DNA，其中IPEP产物的平均基因座检出数高于MDA产物。 结论 MDA方法、IPEP方法均可提高微量检材的STR分型效果。MDA方法的产量高于IPEP方法；IPEP方法的灵敏度高于MDA方法，且对微量DNA的STR分型效果优于MDA方法，因此更适于法医学痕量DNA检测。

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

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.