67个X-SNP位点的分型检测和连锁不平衡检验

摘要

目的 筛选一组在中国汉族人群中具有法医学应用前景的X-SNP位点.方法 根据dbSNP和HapMap两个数据库提供的位点信息和频率数据从X染色体上筛选出67个候选X-SNP位点,采用多重PCR联合基质辅助激光解析电离飞行时间质谱技术检测中国汉族人群428名无关个体,获得67个候选X-SNP位点在中国汉族人群中的频率数据,通过遗传多态性分析和连锁不平衡检验按拟定标准进一步筛选获得具有法医学应用前景的X-SNP位点. 结果 成功获得了67个候选X-SNP位点在中国汉族人群中的等位基因频率数据.Hardy-Weinberg平衡检验示仅有1个位点(rs 12849634)未达到遗传平衡；有2个位点(rs1229078、rs1544545)的最小等位基因频率低于0.3；有6对位点两两存在紧密连锁,有2对位点两两存在轻度连锁.最终确定52个相互独立的、在中国汉族人群中具有法医学应用前景的X-SNP,其在三联体和二联体亲权鉴定中的累积非父排除率分别为0.999 999 999 96和0.999 9995,在女性和男性群体中的累积个人识别率分别为0.999 999 999 999 999 999 999 84和0.999 999 999 999 999 31.结论 本研究筛选出52个相互独立的X-SNP位点,能够满足当前法医遗传学鉴定应用要求,有利于解决特殊亲缘关系的鉴定难题.%Objective To screen a panel of SNP loci on X chromosome(X-SNP loci) that is informative in Chinese Han population and evaluate its potential value in forensic identification. Methods Sixty-seven candidate X-SNP loci were selected according to the information on dbSNP and HapMap. Genomic DNA extracted from blood samples of 428 unrelated Chinese Han individuals were analyzed through multiplex amplification followed by matrix assisted laser desorption/ionization time-of-flight mass spectrometry, and allele frequencies of the 67 X-SNP loci were calculated. In view of the population data and situation of linkage disequilibrium, X-SNP markers promising in forensic identification were sorted out. Results Population data of the 67 X-SNP loci were obtained. Except rsl2849634, no deviations from Hardy-Weinberg equilibrium could be found. Of the rest 66 X-SNP loci, two loci (rsl229078 and rsl544545) were found to be low informative (minor allele frequency<0.3). Closely linked alleles were observed at six pairs of X-SNP loci and slightly linked alleles were observed at two pairs of X-SNP loci. Fifty-two X-SNP loci showing independent inheritance and high polymorphisms were finally selected. The markers were promising in forensic identification. CPE in trio and duo cases were 0.999 999 999 96 and 0.999 999 5, respectively. CDP in female and male populations were 0.999 999 999 999 999 999 999 84 and 0.999 999 999 999 999 31, respectively. Conclusion A panel of 52 informative X-SNP loci showing independent inheritance is selected. These markers meet the needs of individual identification and relationship testing in judicially disputed cases.