Abstract: A pair of primers were designed according to the sequence of specific Mycobacterium paratuberculosis gene of C-2 chromosome(ISMav2), the ISMav2 gene was amplified by PCR and cloned into pMD18-T vector and then the gene sequence was detected.The results showed that the target gene band at a length 246 bp was amplified by PCR,with a homology of 99.6% to the gene sequence reported in GenBank. The experiments had proved that PCR assay possessed a high specificity,DNA bands couldn't be amplified in other bacterial except Mycobacterium paratuberculosis. And the sensitivity test results indicated that PCR assay was more sensitive,which could detect ISMav2 with only 1 pg/mL DNA.The successfully construction of the PCR assay provides strongly technical support for detection,identification and epidemiological investigations of bovine paratuberculosis.

Key words: bovine; brucella; PCR; detection