拓跋鲜卑与四个北方少数民族间亲缘关系的遗传学分析

为了从整体上了解拓跋鲜卑的遗传多态性及其对中国北方少数民族起源的影响,对33例东汉到魏晋时期的拓跋鲜卑遗存的线粒体DNA进行了遗传学分析.结合已发表的中国北方少数民族的数据,在遗传多态性、单倍型组分布状态、Fst遗传距离、系统发育和多尺度分析等方面,对拓跋鲜卑和四个北方少数民族(鄂伦春、鄂温克、达斡尔和蒙古)之间的亲缘关系进行了探讨.结果表明:在多态性方面,拓跋鲜卑表现为与北亚类型具有相似性;在和北方少数民族的亲缘关系上,拓跋鲜卑首先表现出与鄂伦春人之间有更近的亲缘关系,其次是蒙古人、鄂温克人,再次是达斡尔人.     

Development and validation of a custom panel including 183 Y-SNPs for Chinese Y-chromosomal haplogroups dissection using a MALDI-TOF MS system

Y-chromosome SNP haplogroups exhibit geographic structuring in many populations around the world. Therefore, Y-chromosome haplogroups have been widely used to infer paternal biogeographical ancestry and high-resolution paternal lineage classification. In the present study, we designed a customized panel containing 183 Y-SNPs based on previous studies and evaluated the genotyping performance and repeatability, concordance, sensitivity, and ability of analysing case-type samples using a MALDI-TOF MS platform. The average call rate for duplicate typing of any one SNP in the panel was 97.0%. In the concordance and accuracy study, the results of haplogroup designation obtained from MALDI-TOF MS platform were fully consistent with those obtained from the next-generation sequencing (NGS) platform. The optimal amount of template DNA in the PCR seemed to be 10 ng. However, if less DNA (≥156.25 pg) was available, it was still possible to obtain meaningful haplogroup information. For the application part, this panel could be applied for the detection of blood, semen, and buccal swabs samples. Particularly, blood stain on FTA card samples could be dissected by direct PCR amplification on the MALDI-TOF MS platform. Besides, 371 unrelated male individuals from four Chinese ethnic groups (Han, Hui, Mongolian, and Kazak) were detected using this panel. Total 78 terminal haplogroups were found and the haplogroup diversity was 0.933576. The results demonstrate that this panel could be an accurate, fast, and cost-effective method for database construction where the amount of sample material is less of a concern and when the cost of the assay is taken into consideration.     

Inference of population structure and admixture proportion from Y chromosomal data of Chinese population

In the past two decades, Y chromosome data has been generated for human population genetic studies. These Y chromosome datasets were produced with various testing methods and markers, thus difficult to combine them for a comprehensive analysis. In this study, we combine four human Y chromosomal datasets of Han, Tibetan, Hui, and Li ethnic groups. The dataset contains 27 microsatellites and 137 single nucleotide polymorphisms these populations share in common. We assembled a single dataset containing 2439 individuals from 25 nationwide populations in China. A systematic analysis of genetic distance and clustering was performed. To determine the gene flow of the studied population with worldwide populations, we modeled the ancestry informative markers. The reference panel was regarded as a mixture of South Asian (SAS), East Asian (EAS), European (EUR), African (AFR), and American (AMR) populations from 1000 Genomes data of Y chromosome using nonlinear data-fitting. We then calculated the admixture proportion of these four studied populations with 26 worldwide populations. The results showed that the Han and Hui have great genetic affinity, and Hui is the most admixed ethnic group, with 61.53% EAS, 34.65% SAS, 1.91% AFR, 1.56% AMR, and 0.04% EUR ancestry component (the AMR is highly admixed and thus should be ignored). All the other three ethnic groups contained more than 97% EAS ancestry component. The Li is the least admixed population in this study. The combined dataset in this study is the largest of this kind reported to date and proposes reference population data for use in future paternal genetic studies and forensic genealogical identification.     

恩施悬棺人骨mtDNA初步分析

本文以恩施宋代悬棺的骨骼或牙齿样品为对象,经过一系列的处理,获得并扩增了mtDNA的HVSI区的部分序列,通过几个实验初步认定是古DNA.同时通过与部分现代人mtDNA数据的比较参照,对所研究样品单倍群归属进行了初步确定,发现他们主要属于南方类型,但也可能有北方成分.