利用Y染色体全基因组测序数据构建东亚人群Y单倍群谱系树及分歧时间计算

Y染色体为父系遗传、不重组、突变是唯一的多样性来源，各人群具有特异的Y单倍群。Y单倍群呈有规律的地理分布，能揭示人群迁移路线和群体遗传关系，并能重建人群的父系进化历史。Y染色体可实现家族排查功能，方便对犯罪嫌疑人的查找，也逐步被法医学运用所重视。目前构建Y单倍群系统发育树的SNPs只是已被发现的突变，因大量的变异被忽略而产生强烈的偏倚，导致系统发育树的解析度不够。用Y-SNPs和Y-STRs组合计算分歧时间时，因Y-STRs突变太快，古老支系上容易出现多样性饱和而不再具有分辨率，该方法也很难避免Y-STRs多样性的采样偏差。本研究利用Y染色体高覆盖区域测序数据构建稳健的系统发育树，其分支长度可基于突变数目计算出来，按已知突变率将突变数目信息转换成时间，实现准确地估算系统发育树的分歧时间。研究将极大地推进该学科的发展及相关运用技术的进步，研究具有重要的科学意义及运用前景。

Y chromosome is paternal inheritance, no recombination, mutation is the only source of polymorphism, each population has its specific haplogroups. Y haplogroups have specially geographical distribution, which can reveal the prehistoric migration route and genetic relationship of populations, and reconstruct the paternal evolution history. Y chromosome can perform family screening, which is convenient for the search of criminal suspects, and is gradually used in forensic science. At present, the SNPs of constructing phylogenetic trees of Y haplogroups are only mutations that have been found. Because a large number of mutations are unknown, there stays a strong bias, resulting in the lack of resolution of phylogenetic trees. When Y-SNPs and Y-STRs are used to calculate the divergence time, because Y-STRs mutation rate is too fast, it is easy to appear diversity saturation on the old branch and no longer have resolution, and it is difficult to avoid the sampling deviation of Y-STRs diversity. In this study, a robust phylogenetic tree is constructed based on the sequencing data of high coverage region of Y chromosome. The branch length can be calculated based on the number of mutations, and the mutation number can be converted into time according to the known mutation rate, so it could accurately estimate the branches divergence time of phylogenetic tree. The study will greatly promote the development of this research field and the progress of related application technology. The research has important scientific significance and application prospects.