Department of Pathology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China.
Institute of Forensic Medicine, West China School of Basic Science and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China.
Mol Genet Genomic Med. 2020 May;8(5):e1209. doi: 10.1002/mgg3.1209. Epub 2020 Mar 12.
Shaanxi province, located in the upper Yellow River, has been evidenced as the geographic origin of Chinese civilization, Sino-Tibetan-speaking language, and foxtail or broomcorn millet farmers via the linguistic phylogenetic spectrum, archeological documents, and genetic evidence. Nowadays, Han Chinese is the dominant population in this area. The formation process of modern Shaanxi Han population reconstructed via the ancient DNA is on the way, however, the patterns of genetic relationships of modern Shaanxi Han, allele frequency distributions of high mutated short tandem repeats (STRs) and corresponding forensic parameters are remained to be explored.
Here, we successfully genotyped 23 autosomal STRs in 630 unrelated Shaanxi male Han individuals using the recently updated Huaxia Platinum PCR amplification system. Forensic allele frequency and parameters of all autosomal STRs were assessed. And comprehensive population genetic structure was explored via various typical statistical technologies.
Population genetic analysis based on the raw-genotype dataset among 15,803 Eurasian individuals and frequency datasets among 56 populations generally illustrated that linguistic stratification is significantly associated with the genetic substructure of the East Asian population. Principal component analysis, multidimensional scaling plots and phylogenetic tree further demonstrated that Shaanxi Han has a close genetic relationship with geographically close Shanxi Han, and showed that Han Chinese is a homogeneous population during the historic and recent admixture from the STR variations. Except for Sinitic-speaking populations, Shaanxi Han harbored more alleles sharing with Tibeto-Burman-speaking populations than with other reference populations. Focused on the allele frequency correlation and forensic parameters, all loci are in accordance with the minimum requirements of HWE and LD. The observed combined probability of discrimination of 8.2201E-28 and the cumulative power of exclusion of 0.9999999995 in Shaanxi Han demonstrated that the studied STR loci are informative and polymorphic, and this system can be used as a powerful routine forensic tool in personal identification and parentage testing.
Both the geographical and linguistic divisions have shaped the genetic structure of modern East Asian. And more forensic reference data should be obtained for ethnically, culturally, geographically and linguistically different populations for better routine forensic practice and population genetic studies.
陕西位于黄河中上游，语言学谱系、考古文献和遗传证据均表明，该地区是中华文明、汉藏语系和粟作农业的发源地。如今，汉族是该地区的主要人口。通过古 DNA 重建现代陕西汉族的形成过程正在进行中，然而，现代陕西汉族的遗传关系模式、高突变短串联重复（STR）等位基因频率分布和相应的法医参数仍有待探索。
本研究使用最新的华夏 Platinum PCR 扩增系统，成功对 630 名无关陕西男性汉族个体的 23 个常染色体 STR 进行了基因分型。评估了所有常染色体 STR 的法医等位基因频率和参数。并通过各种典型的统计技术探索了综合人口遗传结构。
基于欧亚人群的原始基因型数据集和 56 个群体的频率数据集的群体遗传分析表明，语言分层与东亚人群的遗传亚结构显著相关。主成分分析、多维尺度图和系统发育树进一步表明，陕西汉族与地理上相邻的山西汉族具有密切的遗传关系，并且从 STR 变异来看，汉族是一个具有同质性的人口。除了汉藏语系人群外，陕西汉族与藏缅语系人群共享的等位基因比与其他参考人群共享的等位基因更多。聚焦于等位基因频率相关性和法医参数，所有位点均符合 HWE 和 LD 的最小要求。在陕西汉族中观察到的 8.2201E-28 的联合鉴别概率和 0.9999999995 的累积排除概率表明，所研究的 STR 位点信息丰富且多态性高，该系统可作为个人识别和亲子关系鉴定的有力常规法医工具。
地理和语言的划分塑造了现代东亚的遗传结构。为了更好地进行常规法医实践和人口遗传研究，应该为具有不同种族、文化、地理和语言背景的人群获取更多的法医参考数据。
