Typing With Multiple-locus Variable-number Tandem Repeat Analysis For Yersinia Pestis And Study On The Geneti Relationship

Objective:The genotyping of Yersinia pestis DNA template in different regions of China was carried out by using MLVA genotyping technique to explore the genotyping and genetic relationship of Yersinia pestis in different regions.To provide a more abundant database and information for the tracing of Yersinia pestis in China.Methods:A total of 180 Yersinia pestis(Yersinia pestis)DNA templates from different regions were collected from the Yersinia pestis Department of the Center for Disease Control and Prevention of China Center for Disease Control and Prevention.There are 11 strains in Gansu Province,40 in Tibet,31 in Sichuan,37 in Xinjiang,25 in Qinghai and 36 in Inner Mongolia.In this experiment,"1412" classification scheme was selected,26 VNTR loci were used for MLVA typing,among which 14 loci were used for experimental strains typing in each region.The number of strains after 14 loci typing was more than that of MLVA type and 12 loci were further subdivided by 12 loci.Type.After the experimental analysis,the repetition number of each point is obtained,and the discrimination index of each point is obtained by the software Bio Numerics clustering analysis.In this study,the similarity of the discrimination index is more than 60%,which is divided into a gene group.The resolution index was identical and divided into one genotype.Draw clustering diagram and minimum spanning tree.Results:1.The basic characteristics of strain DNA: the samples were collected from 15 ecotypes and 3 biotypes in China,among which Xinjiang had 5 ecotypes,Gansu strains had 4 ecotypes,Qinghai had 3 ecotypes;There are only two ecotypes in Tibet,Sichuan and Inner Mongolia.Xinjiang and Gansu were derived from ancient and medieval strains,Sichuan and Qinghai from ancient and vole types,Inner Mongolia from voles and medieval strains,and all strains from Tibet from ancient typical strains.The results of MLVA typing at 14 loci in different regions showed that Xinjiang region was divided into 5 groups,among 22 genotypes,19 strains accounted for 51.4 strains,Qinghai region was divided into 4 groups and 14 genotypes.Gansu region is divided into 3 groups,and the number of strains in 6 genotypes B is the highest,accounting for 54.5%.2.The results of "14+12" MLVA genotyping in different regions showed that there were 2 groups and 13 genotypes at 14 loci in Tibet.The sample strains in Tibet were mostly concentrated in group B,and the number of MLVA 8 strains in group B was higher.After 12 locus typing,5 genotypes were further divided into group a and B,and there were 2 groups and 5 genotypes at 14 loci in Sichuan,among which the number of MLVA 2 strains in group A was higher.It was further divided into 5 groups of a-e,9 genotypes,and 14 loci of Inner Mongolia into 2 groups and 7 genotypes,among which group B MLVA 1 was further divided into 9 genotypes by 12 locus typing.The strains were divided into 15 genotypes by 12 locus typing.3.The results of MLVA typing at 14 loci in different regions were as follows: Xinjiang was divided into 5 groups,22 MLVA types,A group had the most MLVA type,19 strains accounted for 51.4%,Qinghai region was divided into 4 groups and 14 genotypes.Gansu region is divided into three groups,6 MLVA type,B group the largest number of strains,54.5%.4.Results of genotyping of different traditional MLVA genotypes: the 14 loci selected in this study divided 180 strains into 8 groups,25 clusters and 64 genotypes.A total of 9 ecotypes were completely distributed in specific gene groups,4 ecotypes were distributed in 2 different groups,1 ecotype was scattered and distributed in 3 gene groups.There were separate groups of vole type and medieval type,which did not cross with the ancient typical strains,and there were no separate groups of the ancient typical strains,which were scattered in different gene groups.5.Phylogenetic relationship: medieval strains evolved from the genes of medieval strains in Inner Mongolia and vole strains from the genes of vole strains in Qinghai;Most of the strains in Xizang and Xinjiang regions are relatively independent,but the genetic loci of a small number of typical strains in Sichuan,Qinghai,Gansu,Tibet and Xinjiang are relatively small,which can be evolved from the same genotypes.Conclusion:1.Only 14 locus MLVA typing method can have higher resolution for strains typing in Xinjiang,Gansu and Qinghai,while in Inner Mongolia,Tibet and Sichuan regions,it is necessary to combine 12 loci to improve the resolution of genotyping.2.Combined with the traditional analysis of Yersinia pestis,Yersinia pestis has a certain stability in genetic evolution.3.In this study,we found that there is not only genetic relationship among strains in the same region,but also the evolution and development of the genetic level in different regions by genotyping.