Abstract：
In the practice of parentage testing, short tandem repeat (STR) genetic inconsistencies occasionally occur and are usually treated as genetic mutations. However, they arise for various reasons. To elucidate the reasons for their occurrence, this study investigates a typical trio. For the D6S1043 locus, the genotype of the biological mother comprised the heterozygous alleles \"7,20\"; that of the child, allele 20; and that of the alleged father, a heterozygous allele \"11,13,\" revealing a 7-step mutation. Different kits were first used to verify the data. The locus map, primers, and core sequences were then analyzed. Ultimately, the STR and single nucleotide polymorphisms of 6q were tested to determine the microdeletion range. The results revealed that this was indeed a true trio, and the underlying cause of the genetic inconsistency at this locus was a microdeletion of approximately 0.74-1.78 Mb in 6q15. Overall, genetic inconsistencies detected during practical work, and particularly rare multi-step mutations, cannot be directly identified as STR mutations. Different tools should be used to examine the causes of genetic inconsistencies from various perspectives and improve the effectiveness of genetic evidence.
摘要：
在亲子关系测试的实践中，短串联重复序列(STR)遗传不一致偶尔发生,通常被视为基因突变.然而,它们的出现有各种原因。为了阐明它们发生的原因，这项研究调查了一个典型的三人组合。对于D6S1043基因座，生物母亲的基因型包括杂合等位基因“7,20”；孩子的基因型，等位基因20；以及所谓的父亲，一个杂合等位基因“11,13”，揭示了一个7步突变。首先使用不同的试剂盒来验证数据。轨迹图，引物,然后分析核心序列。最终,检测6q的STR和单核苷酸多态性以确定微缺失范围.结果显示，这确实是一个真正的三人组合，该基因座遗传不一致的根本原因是6q15中大约0.74-1.78Mb的微缺失。总的来说,在实际工作中发现的遗传不一致，尤其是罕见的多步突变，不能直接鉴定为STR突变。应该使用不同的工具从不同的角度来检查遗传不一致的原因，并提高遗传证据的有效性。
