多重置换扩增技术用于法医学微量DNA检测效果

Effect of multiple displacement amplification on forensic minute DNA analysis

目的探讨多重置换扩增(MDA)技术对法医学微量DNA样品STR检测分型的效果。方法用MDA技术对不同模板量DNA进行全基因组扩增(WGA),扩增产物用实时荧光定量PCR技术定量、用Profiler PlusTM试剂盒检测基因型。结果该方法可对模板DNA增加104～106倍。1ng样品DNA的MDA产物可获得9个STR基因座和Amelogenin性别基因座的准确分型结果;低于0.1ng的样品DNA经MDA扩增后,基因座检出数增加,但可见等位基因不平衡或丢失现象。结论MDA技术可有效增加DNA模板量和提高微量DNA分型效果。但样品DNA量低于0.1ng时,MDA产物的STR分型结果判读须慎重。

Objective To study the effect of multiple displacement amplification （MDA） on forensic minute DNA analysis. Methods Whole genome amplification （WGA） was performed for various amount of sample DNA, and the amplified products were quantitated by real-time quantitative PCR and genotyped by Profiler Plus^TM kit. Results The template DNA can be amplified 10^4 to 10^6 folds by MDA. Using this technology, all 9 STR loci and Amelogenin gene can be correctly genotyped by MDA from 1 ng genomic DNA. When the genomic DNA is not more than 0.1 ng, The loci detected of MDA products are more than the sample DNA not for MDA, but allelic dropouts and allelic imbalance of MDA products was observed. Conclusion MDA is helpful for increasing the ammount of minite DNA and improving the effect of minite DNA analysis. If the sample DNA is not more than 0.1ng, the caution should be put into the STR genotypes of their MDA products.