| Object:SNP(Single nucleotide polymorphism)is a kind of sequence polymorphism of DNA which the human Genome contains the most.SNP was considered as the third genetic marker after the STR(Short Tandem Repeats)and RFLP(restriction fragment length polymorphism).As the accomplishment of Human Genome Project,more and more SNPs were found and some SNPs named AIMs(Ancestry informative markers)have different gene frequency between different population.Differentiating the populations and inferring the ancestry information of individual using a set of these kinds of SNP are well known and applied in the practice.And our study is aim to develop an assay using SNP and build a reference data set,and then study the genetic structure of these population.Ultimately,our study promoted the DNA technology from matching passively using STR to finding positively using SNP in forensic practice and provided the new scientific and technological means for the counterterrorism stability and public security.Method:We selected 28 AIMs which are diallelic gene makers and developed an assay based on capillary electrophoresis apparatus and SNaPshot technology,then we genotyped 998 individuals from 21 populations that were collected by our laboratory.We analysis the result of capillary electrophoresis using GeneMapper and combine these results with the data we collected from 1000 genomes and HGDP-CEPH databank(total 3090 samples,43 populations)together and the methods of Structure cluster analysis and frequency PCA analysis were used to evaluate capacity of differentiation and inference of this panel.663 individuals were used as the test samples to evaluate the inference ability of this panel.Result:The phylogenetic tree demonstrated that populations within a region had a close genetic relationship and the populations from South Asia and Central Asia had a far relationship.The result of STRUCTURE,PCA and systematic tree analyzed using the 28 SNPs demonstrate that this assay could differentiate the populations into six proportions include the South Asia and Central Asia populations.The inference results of 663 individuals by AMP displayed that the system could infer the ancestry origin of the five continentals accurately and the accuracy rate of inference for the Southern Asia and Central Asia is over 90%.Conclusion:In sum,the multiplex system could differentiate the five continental populations and the admixture group.Compared with matching passively using STR traditionally,finding the unknown DNA and inferring the ancestry information of unknown individual using SNP could provide the new trains of thought,methods and theoretic framework in the forensic field of cases detection and family investigation. |
