Establishment Of Forensic DNA Basis Database Of Yunnan Dai People

ObjectY chromosome and euchromosomes of human being is the most important object of forensic DNA. While the X chromosome resives more and more attention to the special concepts of heredity. Preliminary studies found that the genetic polymorphisms difference between populations of the same marker. The population special DNA database is needed to meet the forensic practice. In this article, we are going to build the forensic DNA database of the Dai people from Yunnan province, China.The Asia Y-SNP markers were chocied according to the Human Y-chromosome DNA Haplogroup to analysis to polymorphic in Dai. We also genotyped the Y-STR and X-STR markers for the same DNA samples. Then the Dai from Dehong and Banna were genotyped by 15 autosomal STRs. We also compared the DNA markers for other populations in order to make the DNA database more reliable.MethodWe enrolled 231 unrelated male participants from the Dai settlement of Dehong Longchuan, Yunnan, and they all participated voluntarily in providing informed consent. Genomic DNA was extracted using the Magnetic beads method of blood samples. The Y-SNPs were Anaylsis by MassARRAY technology. And 38 Y-STR and 19 X-STR loci were also analysed. A total of 790 non-related Dai individuals from two Dai settlements (Dehong and Banna) were studied by 15 autosomal STR loci. All the volunteers signed the informed consent to being involved in the study. Allele frequencies and genetic relationship among different populations according to the frequency data was performed using SPSS Version 21.0 and population genetics software.Result1. Y chromosome DNA markers① Y-SNP 43 Y-SNP markers were analysed by 2 multiple PCR panel and 25 of them detects mutations.0 haplogroup is the most major haplogroup in Dai population while O3a2cla sub haplogroup is 40.44 and O2alsubhaplogrous is 30.44%.② Y-STR There are 221 haplotypes in 231 samples while 1 haplotype has 4 cases,3 haplotypes has 2 cases and 2 haplotype has 3 cases.Allelic frequency between 0.01739-0.0043 and combined haplotype polymorphic is 4.2373×10-15. There are 6 NULL allele observed in 38 Y-STR loci while 3 of them came form 1 sample.2. X-STR loci 231 X-STR allele were observed in 19 X-STR loci in 231 male samples. The combine power of discrimination is 1-2.4092×10-13.3. Autosomal STR loci 184 autosomal STR allele and 726 genotype were observed in 790 Dai samples. The combine power of discrimination and combine power of exclusion are 1-2.2282×10-19 and 0.999 999 655. According to the forensic parameters, the FGA loci is the most polymorphic loci in Dai in 15 STR loci.4. Population genetic relationship By compared the Y DNA genetic relationship of Dai and related populations, the Dai show a closer relationship with Daic populations and Sino-Tibetan population. The Dai was affected by part of northern populations on the Y chromosome marker. And the Dai has more closer relationships to Austronesian on autosomal markers. The Y chromosome result maybe suffers by the limited population size.DiscussionThe allelic frequency distribution and statistical genetic parameters of forensic relevance were obtained for 43 Y-SNP markers,38 Y-STR loci and 19 X-STR loci in male population in Dai. And the allelic frequency distribution and statistical genetic parameters of forensic relevance for 15 autosomal STR loci in both genders were obtained. The forensic DNA database was build. By compared the genetic relationship between Dai and related populations, the Dai show a closer relationship to Daic populations. TThe Dai was affected by part of northern populations of the Y chromosome marker. And the Dai has more closer relationships to southern aboriginal people on autosomal markers.