Y染色体STR基因座的异常基因型  

Abnormal genotypes of Y-chromosome STRs

作　　者：李桢[1] 程良红[1] 

机构地区：[1]深圳市血液中心,广东深圳518035

出　　处：《中国输血杂志》2016年第3期273-278,共6页Chinese Journal of Blood Transfusion

摘　　要：目的研究Y-STR的异常基因分型结果,获得更多的Y-STR遗传信息,为法医学鉴定提供依据。方法根据常染色体STR基因座的分型结果,将标本分为2组:"排除父子关系"的为1组,共49个案例,98个标本;"支持父子关系"的为1组,共252个案例,509个标本。采用Chelex方法提取血样DNA,使用Amp Fl STRYfilerTM试剂盒扩增16个Y-STR基因座并通过ABI 3130xl测序仪电泳、分析Y-STR基因型。结果在"支持父子关系"的509个标本中,除了单个基因的一步突变以外,9个标本出现了异常基因型。有3对父子(6个标本)的异常基因型出现在DYS385基因座,表现为三带型(13,14,18,峰高比例约为1∶1∶2)、四带型(13,17,18,20,峰高比例约为2∶1∶1∶1)、四带型(13,18,19,21,峰高比例约为2∶1∶1∶1);有1对父子在DYS439基因座出现双基因(12,13,其峰高比例约为1∶1);另外1对父子,儿子在DYS389II基因座为双基因(28,29,其峰高比例约为1∶1),但其父为正常单基因(28)。在"排除父子关系"的98个标本中有两个标本均在DYS448基因座发生了基因缺失。经统计,单基因座出现多个基因的发生率为1.4%,基因缺失的发生率为0.57%。结论 Y-STR分型中异常基因型的发生率虽然不高,但仍然存在一定的比例,在法医工作中需慎重对待,增加更多的STR基因座有助于正确地判断分析。Objective To study the abnormal genotypes of Y-chromosome short tandem repeat （STR） markers and then to provide more genetic information for forensic practice. Methods All samples were divided into two groups, one contained 49 father-son pairs （98 samples） which were excluded by autosomal STRs testing, another contained 252 father-son pairs （509 samples） which were confirmed by autosomal STRs testing. The DNA were extracted by Chelex 100 and then amplified by AmpFISTR？ Yfiler？ kit. Allele separation and detection were performed in an ABI 3130xl DNA sequencer. Results A total of 9 samples （5 father-son pairs） had abnormal genotypes in the confirmed father-son pairs except some had single mu- tations at single loci. The abnormal genotypes of three father-son pairs （6 samples） were found at DYS385 locus, which con- tained three-banded patterns （13, 14, 18; the proportion of peak height was 1： 1：2）, four-banded patterns （13, 17, 18, 20 ; the proportion of peak height was 2：1 ： 1 ： 1 ） and four-banded patterns （ 13, i8, 19, 21, the ration of peak height was 2 ： 1： 1：1 ）. Double alleles （12, 13; the ration of peak height was 1：1 ） were found at DYS439 locus in a father-son pair （2 samples）. In another father-son pair, only the son has double alleles （ 28,29, the ration of peak height was 1 ： 1 ） at DYS389II locus, but his father was normal at allele 28. There were two samplesboth with absence of genotype at DYS448 lo- cus in the excluded father-son pairs group （98 samples）. By statistical analysis, the ratio of multiple alleles at single locus was 1.4%. The ratio of genotype absence was 0. 57%. Conclusion Although the ratio of abnormal genotypes at the Y- chromosome STRs was very low, more attention should be given to this in forensic practice. Additional STRs would facilitate collection of accurate results.

关 键 词：Y-STR 异常基因型 三带型 四带型 基因缺失 

分 类 号：Q243[生物学—细胞生物学] Q786