法医SNP复合检测体系的构建及应用

目的构建48-SNP位点复合检测体系,用于个体识别、性别鉴定、ABO基因分型。方法采集225份无关个体样本(血斑及口腔拭子),18份案例样本(不同组织及体液斑),选择43个常染色体位点、4个ABO基因位点和1个性别鉴定位点,根据单碱基延伸技术通过GenomeLabTMSNPstream基因分型系统进行SNP分型;并检测体系灵敏度、同一个体不同组织同一性及模拟腐败检材。结果 48-SNP体系分型结果与测序结果的一致性为100%,最小DNA检出量为0.25ng,不同组织来源样本检测同一性很好;利用该体系检测225名无关汉族个体,所有位点均符合Hardy-Weinberg平衡,整个系统的随机匹配概率为9.4×10-18,累积非父排除率(CEP)为0.999 788,累积个体识别率大于0.999 999 999 999 999 99。结论本文48-SNP体系能同时进行个体识别、ABO基因分型和性别鉴定,可以作为现有STR检验体系的补充。

A multiplex SNP genotyping system and its application in forensic science

Objective To develop a multiplexed SNP assay for human identification and evaluate its application value in forensic science.Methods In total,225 samples of healthy unrelated Han Chinese individuals and 18 casework samples were collected.SNPs were selected according to the principle of high heterozygosity and low FST value.Typing results of the SNPs were obtained by a minisequencing approach with 12-plex GenomeLabTM SNPstream Genotyping System.In addition,sensitivity,tissue homogeneity and degraded sample detection ability were evaluated for the system.Results The SNP genotypes obtained by the established typing system were fully concordant with sequencing results.The low DNA detection limit was 0.25 ng.Different tissues of the same person showed consistent SNP types.Allele frequency data for the 48 SNPs were obtained from 225 healthy unrelated Han Chinese individuals.No meaningful deviations from Hardy-Weinberg equilibrium were observed for the tested SNPs.The combined DP was more than 0.999 999 999 999 999 99,and the combined PE and match probability were 0.999 788 and 9.4×10-18 respectively.Conclusions The established SNP panel can be applied to forensic individual identification as a supplementary to the current STR system.