Restriction fragment length polymorphism analysis of open reading frame 5 gene of porcine reproductive and respiratory syndrome virus isolates in Korea - Brief report

The genetic variability of porcine reproductive and respiratory syndrome vi rus (PRRSV) was studied by restriction fragment length polymorphism (RFLP) of polymerase chain reaction (PCR)-amplified fragments among 50 Korean isol ates from open reading frame 5. All Korean PRRSVs were isolated from the fi eld cases after the marketing of an U.S. ATCC VR2332-derived modified live PRRSV vaccine. Combining the restriction enzyme digestion patterns obtained with MluI, HincII, SacII, and HaeIII, we observed 19 distinct RFLP pattern s. Seventeen out of 50 PRRSV isolates (34%) exhibited the modified live PRR SV vaccine RFLP pattern. The genomic variations that have been identified i n the present study seemed to represent characteristic features of the Kore an PRRSV isolates. PCR-based RFLP analysis using several restriction enzyme s provides a good genetic estimate for isolate differentiation.