Identification of Trichinella isolates from China using PCR-RFLP based on COX I gene.

Objective To identify the different Trichinella isolates from China at molecular level.Methods One pairs of primers were synthesized based on the DNA sequence of mitochondrial cytochrome c-oxidase subunitⅠ(COXⅠ) gene of Trichinella.Polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) was applied for the molecular identification of seven swine Trichimella isolates from Henan,Hubei,Yunnan,Xi'an,Harbin,Tongjiang and Tianjin.International reference strains of five species of Trichinella [T.spiralis(T1),T.nativa(T2),T.britovi(T3),T.pseudospiralis(T4)and T.nelsoni(T7)]were used as control.Results The results of electrophoresis of PCR products of Trichinella COXⅠ genes showed that the band(419 bp) of international reference strains of five species of Trichinella(T1,T2,T3,T4 and T7) was the same as seven Trichinella isolates from China.Electrophoresis of COXⅠ gene PCR products digested by restriction endonuclease Tru1Ⅰ(MseⅠ) showed that T2,T3,T4,T7 and Tianjin isolate have their restriction fragments: T2(22 bp,70 bp,327 bp),T3(92 bp,327 bp),T4(419 bp),T7(62 bp,64 bp,70 bp,223 bp) and Tianjin isolate(92 bp,126 bp,201 bp).The other six isolates and T1 have the same restriction fragments(22 bp,70 bp,126 bp,201 bp).Conclusion This study reveals an intraspecies polymorphism in the 92 bp,70 bp and 22 bp fragments of COXⅠ gene of seven T.spiralis isolates from China.The isolates from Henan,Hubei,Yunnan,Xi'an,Harbin,Tongjiang are classified as one group,the Tianjin isolate is classified as another group.