Studies On The Molecular Phylogeny Of Two Types Echinococcus In The Qinghai Province

?Objective?By collecting the specimen of hydatid disease patients after operation in Qinghai Provincial People's Hospital,mitochondrial DNA was extracted from the tissues of parasites.The mitochondrial cytochrome C oxidase subunit gene(Cox1)and nicotinamide adenine dinucleotide(Nad1)sequences of mitochondrial gene were amplified.The obtained sequence of the mitochondrial DNA of Echinococcus was compared with that of other species of Taenia,to further research the classification,phylogeny and origin of the Echinococcus in Qinghai Province.?Methods?Selected Qinghai Provincial People's Hospital 2016-2017 hepatic hydatid patients in general specimens after operation,all specimens confirmed by pathological examination cystic echinococcosis(CE)or alveolar echinococcosis(AE).The DNA purification recovery kit was used to extract and purify DNA and to design primers for the genetic information of Echinococcus sequences on Genbank.Amplify Cox1 and Nad1 genes in mitochondrial DNA with PCR.The amplified DNA was analyzed by DNAStar software,MEGA7.0 software with Neighbor-Jioning(NJ),to measure of mitochondrial Cox1 and Nad1 gene bases,gene variation and their role in species evolution of Echinococcus.By comparing the genetic differences between Qinghai Province Echinococcus and other tapeworm species,identify the variation of Echinococcus,predict the differentiation time and construct the phylogenetic tree of tapeworm.?Results?The Echinococcus granulosus and Echinococcus multilocularis was collected in Qinghai,determinate the sequence of Cox1 and Nad1 base on its mitochondrial DNA and construct the phylogenetic tree.It was found that all E.granulosus was G1 genotypes and all E.multiltilocularis was the Asian strain.the Cox1 and Nad1 gene sequences of E.granulosus were 1600 bp and 894 bp,and there were 7 and 5 different gene sequences,with 15 and 7 mutation sites,respectively.The Cox1 and Nad1 gene sequences of E.multilocularis were 1608 bp and 894 bp,and shared 4 and 1 different gene sequences with 7 and 1 mutation sites,respectively.By comparing the sequences of the Echinococcus and other Tapeworm,it was found that the base composition,the haplotype diversity index and the nucleotide diversity were mostly similar.Through analysing the molecular clock of the echinococcus,it was inferred that the E.granulosus originated 118 thousands years ago,and the E.multilocularis originated from 79 thouands years ago in Qinghai Province.?Conclusion?The dominant strain of E.granulosus in the Qingha Province is the G1 genotype,and the dominant strain of Echinococcus multilocularis is the Asian strain.By comparison with other tapeworm strains,the bases composition are similar with each other.The haplotype diversity index of Cox1 was higher than Nad1,indicating that the Cox1 gene was rich in genetic diversity.In addition,G1 genotype and G3 genotype of E.granulosus,Asian strains and North American strains,European strains of E.multilocularis have shorter divergence times,so they have many similar biological characteristics.