Institute of Forensic Medicine, West China School of Basic Science & Forensic Medicine, Sichuan University, Chengdu, 610041, China.
Institute of Forensic Medicine, West China School of Basic Science & Forensic Medicine, Sichuan University, Chengdu, 610041, China.
Forensic Sci Int Genet. 2020 Jan;44:102197. doi: 10.1016/j.fsigen.2019.102197. Epub 2019 Nov 3.
Mitochondrial DNA (mtDNA) is a key player in numerous multifaceted and intricate biological processes and plays a pivotal role in dissecting the peopling of different populations, due to its maternally inherited property and comparatively high mutation rate. In this study, 119 Tibetan individuals from the Muli Tibetan Autonomous County of China (average altitude above 3,000 m) were employed in mitochondrial genome (mitogenome) sequencing by massively parallel sequencing (MPS) techniques using the Precision ID mtDNA Whole Genome Panel on an Ion S5XL system. The dataset presented 88 distinct haplotypes, resulting in the haplotype diversity of 0.9909. The majority of haplotypes were assigned to East Asian lineages and the distribution of haplogroups of Muli Tibetan significantly differed from reference Tibetan populations. The maximum parsimony phylogeny reconstructed by 119 newly generated mitogenomes revealed 12 major Muli Tibetan lineages. Intriguingly, a Sherpa-specific sub-haplogroup A15c1 with the lack of mutations at 4216 and 15,924 was discerned in our dataset, which suggested that the maternal gene pool of Sherpas may derive from Tibetan populations. The shared haplogroups between Muli Tibetan and lowland Han Chinese hinted that these lineages may derive from non-Tibetans and have already differentiated before their arrival on the Tibetan Plateau. Furthermore, extensive pairwise population comparisons displayed that Muli Tibetan had a closer genetic relationship with ethnically or linguistically close Nyingtri Tibetan, Nyingtri Lhoba and Chamdo Tibetan populations. Genetic affinity was also observed between the Muli Tibetan and North Han Chinese. Collectively, the results generated in this study enriched the existing forensic mtDNA database and raised additional interest in the application of whole mitogenome sequencing in forensic investigations.
线粒体 DNA（mtDNA）是众多多方面和复杂的生物学过程中的关键参与者，由于其母系遗传性质和相对较高的突变率，在解析不同人群的迁徙中起着至关重要的作用。在这项研究中，使用 Ion S5XL 系统上的 Precision ID mtDNA 全基因组面板，通过大规模平行测序（MPS）技术对来自中国木里藏族自治县（平均海拔超过 3000 米）的 119 名藏族个体进行了线粒体基因组（mitogenome）测序。该数据集呈现了 88 个不同的单倍型，导致单倍型多样性为 0.9909。大多数单倍型被分配到东亚谱系，而木里藏族的单倍型组分布与参考藏族人群显著不同。通过 119 个新生成的线粒体基因组重建的最大简约系统发育树揭示了 12 个主要的木里藏族谱系。有趣的是，我们的数据集中发现了一个特定于夏尔巴人的亚单倍型 A15c1，其在 4216 和 15924 处没有突变，这表明夏尔巴人的母系基因库可能来自藏族人群。木里藏族与低地汉族之间的共享单倍型群提示这些谱系可能来自非藏族人，并且在他们到达青藏高原之前已经分化。此外，广泛的成对人群比较显示，木里藏族与在种族或语言上相近的比如林芝藏族、林芝珞巴族和昌都藏族人群具有更密切的遗传关系。木里藏族与北方汉族之间也存在遗传亲和力。总的来说，本研究的结果丰富了现有的法医 mtDNA 数据库，并提高了在法医调查中应用全线粒体基因组测序的兴趣。
