贵州多民族人群基因座遗传突变率研究

Exploration into Rate of Genetic Mutation with STR Loci among Multi-ethnic Populations in Guizhou

探讨贵州地区人群亲权鉴定特异性基因座的选择、亲权指数的优化及涉及突变的计算,希冀为相关理论研究与应用提供实际参考依据,以确保DNA亲子鉴定结论的准确性。收集本院司法鉴定中心2012年至2019年间的亲子鉴定案例5224件。血卡与毛发样品经直扩、Chelex法或成品试剂盒提取DNA样本,使用Goldeneye20A/20NC或美国AB公司的Identifiler-plus/ID试剂盒进行PCR复合扩增,扩增产物用ABI-3500xL序列分析仪进行电泳分离和激光扫描分析。结果显示,基于40个常染色体STR基因座,所分析5224例亲子鉴定案件中有140例出现基因突变,突变率为2.68%。最常发生突变的三个基因座分别为D12S391(突变21次),D18S51和Penta E(各突变15次)。汉族、布依族、苗族平均突变率分别为2.33%、2.47%、4.01%。突变源于父亲、母亲的比例为2.74∶1。父母生育年龄低于20岁或者高于60岁时,其子代更易发生基因突变。故基因突变表现出其基因座位置、个体性别及年龄差异。当然,许多研究发现突变与地域也有关联性。本文所得数据对贵州地区人群亲缘关系鉴定与研究以及亲权指数的计算具有参考价值。

This article is to explore about the selection of specific STR loci for paternity identification among the populations in Guizhou province,together with the optimization of causal paternity index(PI)and calculation of PI under occurrence of mutation,purposing to provide practical reference for relevant theoretical enquiry and application to carry on and ensure the validity of the conclusion of DNA parentage analysis.With 5224 parentage cases collected from 2012 to 2019 in the college’s forensic medicine center,the DNA samples were extracted through Chelex method or commercial kit/direct amplication.The Goldeneye20A/20NC or AB’s Identifiler-plus/ID kits were used for PCR multiplex amplification.The amplified products were separated by electrophoresis and analyzed by laser scanning with ABI-3500xL sequencer.From the involving 40 autosomal STR loci,mutations occurred into 140 cases out from the 5224 ones,bringing forth the average mutation rate of 2.68%.The three most frequently mutated loci were D12S391(21 mutations),D18S51 and Penta E(15 mutations each).Through analysis of race,gender and age of the individuals related to the cases occurring of mutation,it was revealed that the populations of ethnic-Han/Buyi/Miao demonstrated their average mutation rates as the respective 2.33%,2.47%and 4.01%;the paternal-to-maternal ratio regarding to mutation was 2.74׃1;genetic mutations were more likely to take place into the offsprings from the parents under 20 or over 60 years old.Therefore,STR loci were shown of mutation differences correlating to their chromosomal positions,involved individuals’gender and age.Certainly,many publications reported that mutation is also pertinent to geographical regions of people’s living.The data obtained here should be of providing reference for consanguinity enquiry and identification and PI calculation among the populations in Guizhou.