Y-STR非逐步突变机制研究及在男性家系调查的应用展望  

The research of non-stepwise mutation model and its application in the male lineage genetic marker Y-STR

作　　者：张艺严 黄磊 陈雪云[3] 邓钧 何玮[3] 翟滇[3] 聂慧杰 杨广森 程宝文 Zhang Yiyan;Huang Lei;Chen Xueyun;Deng Jun;He wei;Zhai Dian;Nie Huijie;Yang Guangsen;Cheng Baowen(School of Forensic Medicine,Kunming Medical University,Kunming 650500,China;Institute of Criminal Science and Technology,Kunming Public Security Bureau,Kunming 650000,China;Yunnan Provincial Public Security Department,Kunming 650031,China)

机构地区：[1]昆明医科大学法医学院,昆明650500 [2]昆明市公安局刑事科学技术研究所,昆明650000 [3]云南省公安厅,昆明650031 [4]云南公安刑事科学技术研究所,昆明650031

出　　处：《国际遗传学杂志》2023年第5期356-361,共6页International Journal of Genetics

基　　金：北京市现场物证检验工程技术研究中心(2021CSEEKFKT08)。

摘　　要：Y-STR是最常用的男性家系调查遗传标记之一, 其突变机制多以经典的逐步突变理论来考量。然而, 逐步突变并不能完全解释多步突变、扩增条带数量增减及基因型缺失等现象。非逐步突变的机制如非等位同源重组和基因转换, 前者介导DNA复制、缺失产生多带分型及基因型缺失, 后者介导二拷贝基因由"杂合子"分型突变为"纯合子"分型。此类突变机制产生的特殊分型可在法庭科学DNA数据库中核心、优选基因座中观察到, 并且父子对中稳定遗传、存在一定地域分布差异。经非逐步突变机制产生的特殊分型在男性家系调查中可用于标记、细分大家系, 在家系排查设置容差步长、突变率调查时应考虑非逐步突变机制造成特殊分型、多步突变的影响。本文综述非逐步突变机制及其所致特殊分型、多步突变, 为其更好应用于男性家系调查提供初步理论基础。Y chromosome short tandem repeats is one of the most commonly used genetic markers in forensic science.The"classical"stepwise mutation model(SMM)mostly considered as main mutation mechanism under of Y-STR mutation.With interpretation of some phenomena such as multi-allele pattern,multi-step mutation,and null allele,SMM doesn’t make sense.Non-stepwise mutation model includes non-allelic homologous recombination and gene conversion.Duplication and deletion are driven by NAHR to produce multi-allele pattern and genotype of null allele.The two-copy Y-STR loci underwent gene conversion,which changed the"heterozygous"typing to the"homozygous"type.Particular types produced by such non-stepwise mutation model can be observed in forensic science DNA database core and preference loci.It can also observe in father-son pairs and there are some distinctions in its geographic distribution.The kind of gene type can be used to identify and separate minor families from the main lineage in male family investigations.When determining tolerance step size and mutation rate investigation,it is important to take particular type and multi-step mutation caused by non-stepwise mutation model into account.Here,the non-stepwise mutation model and its resulting particular type and multistep mutation were reviewed.It provides a preliminary theoretical basis for better application in male lineage screening system.

关 键 词：法医物证学 Y-STR 突变机制 NAHR 基因转换 

分 类 号：D919[医药卫生—法医学]