Forensic Application And Population Genetic Structure Of Some Guizhou Human Populations Inferred From InDel Genetic Markers And Combined Microarray Data

Objective:Given their linguistic and cultural uniqueness,we selected seven ethnic groups in Guizhou with the largest number of population size.Using In Del genetic markers and combined gene chip typing technology,we studied the genetic structure,ethnic origin and forensic application value of these seven populations in Guizhou.Methods:1618 bloodstain samples were collected from unrelated volunteers living in the Guizhou of Southwest China.The population sample sizes were as follows:Han（N=200）,Miao（N=311）,Bouyei（N=205）,Dong（N=148）,Yi（N=152）,Sui（N=511）and Chuanqing（N=91）.We genotyped 30 In Del loci in 1618 individuals from the above seven Guizhou populations and 50 In Del loci in 591 individuals from Han,Dong,Yi and Chuanqing,using the Qiagen Investigator^?DIPplex kit and AGCU In Del 50 kit respectively.Amplified fragments were isolated using the capillary electrophoresis in an Applied Biosystems 3500XL Genetic Analyzer.Genotypes were determined by Gene Mapper ID-X software v1.3.Then,we merged our In Del with previously published population data from worldwide.We use software like STRAF,Arlequin v3.5,SNP Analyzer v2.0,MVSP v3.2,phylip v3.6,DISPAN,Genepop v4.2,MEGA v6.0,STRUCTURE v2.3.4 to evaluate the forensic efficacy infer the genetic relationship between the studied populations and other previous published reference populations.We collected saliva samples from 14 Chuanqing individuals from Bijie Prefecture and 15 Sui individuals from Sandu Prefecture.Human genomic DNA was extracted using the QIAamp DNA Blood Mini Kit,genotyping was performed on the Illumina We Gene Arrays covering 690,193 SNPs at the We Gene genotyping centre,Shenzhen.Then,we merged our In Del and microarray data with previously published population data of genome-wide level from worldwide.We use software like smartpca,ADMIXTURE,f statistics,qp Wave and qp Adm to evaluate their efficiency of forensic kits in forensic application and infer the genetic structure and admixture for populations in Guizhou.Results:（1）We have succeeded in obtaining the first batch of genotype data of30 In Dels included in the Investigator^?DIPplex kit in seven Guizhou populations,50In Dels included in the AGCU In Del 50 kit in four Guizhou populations,and 690,193SNPs in Sui and Chuanqing people.After applying the multiple tests of Bonferroni correction,there are no significant departures from LD,all studied markers were found to be in Hardy-Weinberg equilibrium.The allele frequency of insertion ranges from0.0493（HLD111）to 0.9440（HLD118）and 0.1933（rs72085595）to0.8187（rs140323077）.The polymorphism information content varies from0.0894（HLD111）to 0.3750（HLD136）and from 0.2878（rs67700747）to0.3750（rs5787309）.The combined power of discrimination varies from0999999999966088（Dong）to 0.999999999979629（Han）and from0.9999999999999999995823（Chuanqing）to 0.9999999999999999997787（Yi）.The combined power of exclusion varies from 0.984095（Bouyei）to 0.986654（Chuanqing）and from 0.9995625（Dong）to 0.9997599（Han）.（2）The frequency heat map showed that the 30 markers in the Investigator^?DIP plex kit have different allele frequencies in different populations,especially among intercontinental populations.Our population genetic results from principal component analysis,genetic distance calculation,phylogenetic tree construction and STRUCTURE analysis suggested that the seven Guizhou populations genetically cluster with populations with the same linguistic and geographic affilation.For example,the Tai-Kadai-speaking Guizhou Sui,Bouyei,Dong are grouped with Guangxi Zhuang,Guangxi Gelao,Liuzhou Zhuang,and Vietnamese.The Hmong-Mien-speaking Guizhou Miao are grouped with Guangxi Yao,and Guangxi Miao.The Sinitic-speaking Han and Chuanqing show a relatively close genetic affinity with Han groups in various regions of China.Tibeto-Burman-speaking populations are dispersed in cluster analysis except for Tibetan populations.We also found a closer relationship between the Guizhou Yi and Guizhou Han,Guizhou Miao,and Chengdu Han.（3）The analysis of microarray data confirmed that Guizhou Chuanqing is genetically similar to southern Han Chinese,Miao,She and Tujia populations.The Y chromosomal lineages characteristic in Han Chinese reach high frequencies in Chuanqing.The maternal mt DNA lineages of our samples are consistent with the general profile of this region with high frequency of B4,D4 and M7.The genetic structure of Guizhou Sui is genetically closer to the one of Dai people in Xishuangbanna.Conclusion:（1）The 30 In Dels included in the Investigator^?DIPplex（?）kit and 50In Dels included in the AGCU In Del 50 kit had good polymorphism in the studied Guizhou populations,which could be used for individual identification independently and be used as a supplemental tool for some special paternity testing cases.Forensic parameters of 47 autosomal In Dels contained in the AGCU In Del 50 kit were all higher than those based on 30 In Dels contained in Investigator^?DIPplex kit.AGCU In Del 50kit is more suitable for Chinese people.（2）Miao,Dong,Bouyei and Sui groups of Guizhou genetically cluster with populations who share the same linguistic and geographic affiliation.The Han and Chuanqing of Guizhou genetically cluster with southern Han Chinese.Guizhou Yi shows a distinct genetic profile from Tibeto-Burman speaking populations in different regions.The Guizhou Yi had a closer genetic relationships with the Honghe Yi group.（3）From the analysis results tend to think that Guizhou Chuanqing is the Han population migrated from the north or a population with Han genetic characteristics formed during massive population expansion and genetic admixture for nearly two thousand years.The Sui group in Guizhou is a typical group of Tai-Kadai-speaking.The results show that the Sui group in Guizhou are an ancient ethnic group living in southern China thousands of years ago.