口腔粘膜脱落细胞DNA多态性分型检测在法医学应用的初步研究

目的研究各类口腔粘膜脱落细胞的微量生物性捡材中DNA提取和检验的方法,初步论证牙刷等载体作为法医物证检材的可能性。方法分别采用Chelex-100法、有机萃取法、联合抽提法三种方法提取口腔粘膜脱落细胞载体的样本DNA,进行CTTv四个STR位点单步复合扩增和两步级联扩增两种STR-PCR方式的扩增及各位点的等位基因检测。结果实验样本中,除了1例牙刷和2例牙签未能STR位点的正确分型外,其余各无关个体口腔粘膜脱落细胞载体均可以得到与标准血痕阳性相同的STR基因型。结论根据检材的PCR相对模板DNA量,选择适宜的DNA多态性检测分型方法,各类常见的含有口腔粘膜脱落细胞检材可以进行DNA检测分型,这类检材在法医检案中具有应用价值。

Primary study on forensic application of oral mucosa exfoliative cells DNA polymorphism

Objective To study the DNA extraction and the Allelic gene typing in various carriers of oral mucosa exfoliative cells for exploring and reasoning its practicality for forensic physical evidence. Methods Chelex-100 extraction method, organic solvent extraction method and the combination extraction method were used to extract the sample DNA followed with CTTv -STR loci typing and comparison by two PCR modes (ONE-Step Multi-STR PCR/TWO-Step Cascading PCR). Results A toothbrush and 2 toothpicks from one volunteer failed to confirm STR locus typing, but the ratios of DNA typing accounted for a percentage of 98% in 200 such carrier samples by standard bloodstain genotypes. Conclusion With careful selected methods for matching quantity of DNA samples and the type of materials, various carriers of oral mucosa; exfoliative cells can be typed by DNA analysis, which is useful in forensic identification.