74-plex SNPs复合检测体系在中国人群中的族群推断研究

The ancestry inference of Chinese populations using 74-plex SNPs system

使用一组祖源SNP可以分析某人群的遗传成分,推断某个体的族群来源。本课题组前期筛选出74个SNP位点实现了撒哈拉以南的非洲、北非、欧洲、美洲、大洋洲、南亚、西南亚、东亚、东北亚和东南亚等10个地理区域人群的推断,并基于Mass ARRAY质谱分析技术构建了74-plexSNPs复合检测体系。本研究利用该体系对14个中国人群1371份样本进行基因分型,验证评估该体系对中国人群的区分能力和法医学应用效能。首先,基于全球57个人群3628份个体构建参考人群分型库,采用Structure分析和等位基因频率热图等方法进行人群区分能力评估;然后,选取千人基因组计划中3个人群(不包含在参考人群分型库中)及本实验室检测的14个人群共计1654个体作为测试数据集,通过似然比和族群成分等统计分析,评估该体系对实际样本的族群来源推断能力。结果表明,DNA的量最低为1.5ng时,74个SNP均可正确判型,适用于微量检材的检测;该体系对全球10个地理区域人群有区分能力,针对测试人群中欧洲、美洲、南部非洲个体族群来源推断的准确率为95.4%、不排除率为1.06%,东亚个体推断的准确率为71.0%、不排除率为17.9%,东南亚个体推断的准确率66.4%、不排除率为33.3%。该方法可以为实际案件侦察提供线索。

A panel of ancestry informative SNPs(AISNPs) can be used to analyze the genetic components of a population and infer the ancestral origin of a DNA sample. Previously, we have selected a 74-AISNPs panel and used it to infer the ancestry of unknown individuals in the following ten geographical regions: Sub-Saharan Africa, North Africa, Europe, Pacific, Americas, Southwest Asia, South Asia, North Asia, East Asia and Southeast Asia. We have also established a 74-plex SNPs assay based on SEQUENOM system. In the present study, we genotyped 1371 individuals from 14 populations of China using this multiplex assay, and validated its ability to infer the ancestry in Chinese populations. Firstly, based on the reference database of 3628 individuals from 57 world populations, Structure and Heatmap were employed to evaluate the population differentiation capacity. The training data include 1654 individuals from 14 Chinese populations and 3 populations from 1 K Genome, which are not included in the reference database. Then the likelihood ratio and ancestry components were analyzed for individual ancestry assignment using the 74-plex SNPs. The minimum amount of DNA required for a full genotype of the 74 SNPs is 1.5 ng, which is applicable for forensic analysis. The results demonstrate that this system can be used in differentiating the population from ten geographical regions. The ancestry inference accuracy for EUR/SAFR/AME population is 95.4%, 71.0% for East Asia and 66.4% for Southeast Asia respectively. The ancestry inference inclusive rate for EUR/SAFR/AME population is 1.06%, 17.9% for East Asia and 33.3% for Southeast Asia respectively. The results suggest that this method can be used in forensic investigations of criminal cases.