DIP-STR在不平衡混合DNA样本中的分析研究

当前,DNA检验技术作为打击犯罪的利器,在法医鉴定中发挥着巨大作用。但对于性侵、暴力犯罪等案件中提取的混合DNA样本,尤其是从受害人或嫌疑人的接触物上采集的高度不平衡混合DNA样本,利用常染色体STR检验方法得到的结果通常不是很理想。由于PCR扩增偏倚,从混合样本中检测出痕量DNA分型是一个巨大的挑战,也是当前法医DNA检验的一个难点。近年来的研究显示,利用新型连锁遗传标记DIP-STR,即结合缺失或插入多态性片段DIP(deletion–insertion polymorphisms)和STR的连锁位点,可以用来检测出混合DNA样本中任一性别和细胞起源的微量DNA,甚至在DNA混合比例高达1:1000时,DIP-STR标记的灵敏度、特异性仍旧相对较为理想。因此,DIP-STR标记的分析可以作为常染色体STR检验的有效补充。本文将对DIP-STR在不平衡混合DNA样本分析中的研究背景、方法及其应用前景进行综述。

The application of DIP-STR in the analysis of unbalanced DNA mixtures

At present,forensic DNA typing plays an important role in forensic science as an effective approach against crime.However,for the mixed DNA samples extracted from sexual assaults and violent crimes,especially the highly unbalanced mixed DNA samples collected from the victims or suspects’contacts,the results obtained by using autosomal STR processing are usually not very satisfactory.Because of PCR amplification bias,It is a tremendous challenge to detect trace DNA typing from mixed samples and a difficulty to forensic science.In recent years,a novel molecular marker,named DIP–STR that relies on pairing deletion–insertion polymorphisms(DIP)with STR,allows for the unambiguous genotyping of a minor component in the presence of a major component,the sensitivity and specificity of DIP-STR markers were still relatively ideal even when the DNA mixture ratio was as high as 1:1000.Therefore,DIP–STR analysis can be used for an effective supplement of autosomal STR.This review focus on the research background and the application of DIP-STR in the analysis of unbalanced genomic mixtures.