目的：对X染色体上的插入/缺失（Insertion/Deletion，InDel）遗传标记进行研究，筛选18个基因座建立可用于中国汉族人群法医DNA鉴定的辅助分型系统。方法采用人类基因组浏览器和dbSNP数据库筛选得到18个X-InDel基因座，用Primer 3软件包设计多重复合扩增PCR引物，依据扩增片段长度分为3组，分别用FAM、HEX和TAMRA三种荧光素标记，建立多重PCR体系。对中国汉族和主要的四大少数民族（回族、维族、蒙古族和藏族）进行群体遗传学调查及对比分析。结果成功研制了一个包含18个X-InDel基因座和Amelogenin性别鉴定基因座的复合荧光多重PCR扩增体系，命名为InDel X-18PLEX系统。多态性调查显示这18个X-InDel基因座在5个主要民族中等位基因频率分布符合Hardy-Weinberg平衡，但各等位基因的频率分布差异具有统计学意义。在中国汉族人群中，该系统在女性群体和男性群体的累积个人识别率分别为0.9999994、0.99988，在三联体和二联体的累积平均排除率分别为0.999992和0.99。结论 InDel X-18PLEX系统能够满足成为法医DNA鉴定辅助性试剂盒的要求，可以成为部分疑难案件的补充分析工具。%Objective To investigate Insertion/Deletion (InDel) polymorphism on the X chromosome and to screen 18 InDel loci for the Chinese Han population as a forensic DNA typing system auxiliary. Meth-ods Eighteen X-InDel markers were selected using the Human Genome Browser and dbSNP database. Multiplex PCR primer pairs of selected X-InDel markers were designed using Primer 3 software and di-vided into 3 groups according to the amplified fragment length, labeled by FAM, HEX and TAMRA fluorescence dye, respectively. The population genetics research and comparative analysis of Chinese Han nationality and 4 main minorities, the Hui, Wei, Mongol, and Tibetan nationalities, were investigated with the system. Results A new multiplex genotyping system, named InDel X-18PLEX, was successfully developed and validated, consisted of 18 X-InDel markers on the X chromosome and 1 Amelogenin gen-der marker. No deviation from Hardy-Weinberg equilibrium expectations was detected in the distribution of genotypes in the 5 investigated ethnic groups. However, there was significant difference between their distributions. From the investigation of Han nationality, high female (0.999 999 4) and male (0.999 88) overall discrimination power values were obtained, as well as high overall mean exclusion chance values in trios (0.999 992) and in duos (0.99). Conclusion InDel X-18PLEX meets the requirements as a forensic DNA complementary kit, providing effective supplementary analytical tools for difficult cases.
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