1例Y-STR突变的叔侄关系鉴定

Identification of an Uncle-Nephew Relationship with a Y-STR Mutation

摘要: 目的：探讨叔侄关系鉴定中Y-STR发生突变时的鉴定策略。方法：采集被鉴定人、疑为被鉴定人的叔叔以及被鉴定人生母的血样。采用沿溯21Plex试剂盒、GoldeneyeTM 22NC试剂盒和GoldeneyeTM 27Y试剂盒对常染色体STR和Y染色体STR进行复合扩增，毛细管电泳分析各STR分型。结果：采用叔侄指数(avuncular index, AI)定律分别计算有无生母参与时的AI值，生母没有参与时累积叔侄指数(CAI)为50.5278，叔侄关系概率(W)为0.9806；生母参与时，CAI为2909.5629，W为0.9997。GoldeneyeTM 27Y试剂盒进行Y-STR分型时发现，在DYS570基因座上被鉴定人与疑为被鉴定人叔叔的基因分型结果不一致，其余26个Y-STR基因座的分型结果完全一致。根据基因分型结果不排除两被鉴定人之间具有叔侄关系。结论：对于叔侄关系鉴定，应采集家族中多个已知血缘关系的个体参与鉴定，综合运用多种遗传标记(常染色体STR、性染色体STR)和多系统进行联合分析。当出现不符合遗传规律的现象时应综合分析不能随意否定二者的亲缘关系。

Abstract: Objective: Discussing the identification strategy for Y-STR mutations in uncle-nephew relationship testing. Method: Blood samples were collected from the identified person, the alleged uncle of the identified person, and the biological mother of the identified person. Yansu 21Plex kit, GoldeneyeTM 22NC kit and GoldeneyeTM 27Y kit were used for multiplex amplification of autosomal and Y chromosome STR loci, followed by capillary electrophoretic analysis for each STR genotype. Result: According to the avuncular index (AI) law, the AI values are calculated separately when there is or no presence of a biological mother. When the biological mother is not involved, the cumulative avuncular index (CAI) was 50.5278, and the probability of avuncular relationship (W) was 0.9806; when the birth mother participated, CAI was 2909.5629 and W was 0.9997. During Y-STR typing using the GoldeneyeTM 27Y kit, inconsistent results were observed in the genetic typing of the identified person and the alleged uncle at the DYS570 locus. However, the typing results of the remaining 26 Y-STR loci were completely consistent. Based on the genetic typing results, it is not ruled out that there is an uncle-nephew relationship between the two individuals. Conclusion: For the identification of uncle-nephew relationship, it is necessary to collect several individuals with known blood relationship in the family to participate in the identification, and comprehensively use a variety of genetic markers (autosomal STR, sex chromosome STR) and multiple systems for joint analysis. When the phenomenon does not conform to the law of heredity should be comprehensive analysis can not arbitrarily deny the genetic relationship between the two.