MII-Y-STR单倍型遗传结构与Y染色体单倍群关联性的法医学祖先推断探索研究

One of the cutting-edge of science research for forensic genetics is to infer ethnic origin or bio-geographical ancestry of DNA samples in the scene of a crime. Y chromosome SNP haplogroups could provide important information for tracing the male line of descent. One of the challenges for forensic geneticists is the cost and time typically needed to genotype an appropriate number of SNPs to assign a given Y chromosome to a haplogroup. Our previous researches have indicated that the haplogroup information of a given Y chromosome predicted by its STR haplotypes could be used to inferred the ethnic origin or bio-geographical ancestry of DNA samples. The aim of this project is to realize this possibility by constructing a suite of modern machine learning algorithms which can automatically classify and predict haplogroups based on allelic data from a suite of Y-STRs. To achieve this aim we will, firstly, explore the maximally informative independent Y-STR markers (MII-Y-STRs) in Y chromosome as candidates for haplogroup prediction, and clarify the relationships between MII-Y-STR haplotypes and Y chromosome haplogroups. Then, the adaptability of the haplogroup prediction method for forensic genetics will be evaluated.

案件现场生物检材的个体祖先来源推断是法医学研究前沿之一。Y染色体单倍群是推断男性个体祖先来源的重要手段。目前通过繁复的SNP分型来判定Y染色体单倍群的方法严重地限制了Y染色体单倍群在法医学中的应用。我们前期的研究结果提示，通过Y-STR单倍型可以预测样本Y染色体单倍群并用于祖先推断。因此，本课题旨在以我们提出的高信息性独立型Y-STR标记（MII-Y-STR）为基础，对MII-Y­STR单倍型遗传结构与Y染色体单倍群的关联性进行研究，继而开展其用于法医学祖先推断的探索研究，包括：1）筛选适于单倍群预测的MII-Y-STRs；2）阐明MII-Y-STR单倍型遗传结构与Y染色体单倍群的关联性，并构建Y染色体单倍群预测模型和算法；3）在人群MII-Y-STR单倍型遗传结构和Y染色体单倍群关联数据的基础上，对预测模型进行验证和法医学评价，为法医学生物检材个体祖先推断提供新技术。

案件现场生物检材的个体祖先来源推断是法医学研究前沿之一。Y染色体单倍群是推断男性个体祖先来源的重要手段。目前通过繁复的SNP分型来判定Y染色体单倍群的方法严重地限制了Y染色体单倍群在法医学中的应用。本研究的目标是找到群体间差异显著、信息含量高且相互独立的高信息性独立型Y-STR标记（maximally informative & independent marker，MII-Y-STR），并对其进行适当组合，提高了单倍群预测精准度和效率，为基于Y-STR单倍型的Y染色体单倍群预测提供了有益探索，为相关试剂盒的开发提供新的参考信息。本课题实现的研究目标，包括：1）筛选了适合于Y染色体单倍群预测的MII-Y-STR标记；2）明确了MII-Y-STR单倍型遗传结构与Y染色体单倍群之间的关联性；3）构建了基于MII-Y-STR单倍型遗传结构的Y染色体单倍群预测模型并对其用于法医学祖先推断进行了探索和评价。