高分辨Y染色体遗传标记的法医复杂家系搜索研究

One of the cutting-edge of science research for forensic genetics is pedigree search based on DNA samples in the scene of a crime. It is important for narrowing the scope of suspects and guiding investigations. Y chromosome STR (Y-STR) has been successfully used for forensic pedigree search. However, when there are a few mismatched loci of Y-STR between the crime scene sample and all the reference male lineage samples, it is very difficult to determine whether there is any suspect family in the reference male lineage. This study aims to explore forensic complex pedigree searches based on high-resolution Y-chromosomal genetic markers, including: 1. to establish high-resolution Y-SNP haplogroups for forensic science and to clarify the distribution patterns of 6 ethnic groups in China; 2. to find out Y-STR with appropriate mutation rate to provide new markers for forensic complex pedigree searches; 3. to clarify the correlation between different distant relatives in same male lineage and Y-STR mutation distribution based on high-resolution Y-SNP haplogroups; 4. To establish a forensic complex pedigree search model based on the knowledge of high-resolution Y-SNP haplogroups and Y-STR haplotypes with different mutation rates; 5. To establish a next-generation sequencing method for high-resolution Y-SNP haplogroups and Y-STR haplotypes to provide new technologies for forensic complex pedigree searches.

法医学研究前沿之一是基于案件现场检材的家系搜索。这对缩小嫌疑人范围，指导案件调查至关重要。Y染色体STR（Y-STR）用于法医家系搜索已经取得了巨大成功。然而，犯罪现场检材与所有参比父系样本有少数Y-STR不一致时，判断参比父系中是否有嫌疑人家系十分困难。这是法医Y-STR家系搜索急需解决的科学问题。本课题旨在开展基于高分辨Y染色体遗传标记的法医复杂家系搜索研究，包括：1.建立法医学需要的高分辨Y-SNP单倍群并阐明在中国6个民族及群体的分布规律；2.探索发现突变率合适的Y-STR，为法医复杂家系搜索提供新标记；3.基于高分辨Y-SNP单倍群，阐明家系中远近亲与Y-STR突变分布的相关性，为法医复杂家系搜索提供新理论；4. 建立法医复杂家系搜索模型；5.建立高分辨Y-SNP和Y-STR新一代测序方法，为法医复杂家系搜索提供新技术。

基于案件现场检材的家系搜索是法医遗传学研究前沿之一，这对缩小嫌疑人范围，指导案件调查至关重要。本课题聚焦于法医所需高分辨Y-SNP单倍群与Y-STR单倍型的有机结合，即Y-SNP-STR单倍群/单倍型分析体系的建立。1. 构建了法医学所需的高分辨 Y-SNP系统进化树，包含256个Y-SNP位点，定义253种单倍群。含有27个Y-STR单倍型结果的样本会被定位到这些高分辨单倍群中，实现了法医系谱学和高分辨率的有机结合。阐明了Y-SNP-STR单倍群/单倍型在我国汉族、藏族、蒙古族、回族、维吾尔族、壮族、柯尔克孜族、彝族、羌族及黎族等10个民族的分布规律；2.开发了9个慢突变Y-STR，为法医复杂家系搜索提供了新标记；3.基于高分辨Y-SNP单倍群，用单倍型错配率揭示了Y-STR在单倍群内的突变分布规律，为法医复杂家系搜索提供了新理论；4.基于高分辨 Y-SNP-STR单倍群/单倍型，建立了法医复杂家系搜索模型并研制出软件YHP（Y Haplogroup Predictor），提供了人工智能新技术；5.建立了两套高分辨 Y-SNP-STR单倍群/单倍型检测体系。一套基于大规模并行测序（MPS）技术；另一套基于SNaPshot分型技术，包含一个初检体系和九个细分体系，适用于法医DNA实验室广泛使用的激光荧光毛细管电泳平台。Y-SNP-STR分型为法医复杂家系搜索提供了新技术。