Development of restriction fragment-length polymorphism method to differentiate five subtypes of feline immunodeficiency virus

Feline immunodeficiency virus (FIV) isolates have been classified into five subtypes (A to E) based on the sequences of the env variable V3 to V5 regi on. In this study, we sequenced a partial gag region of 4 and 3 isolates be longing to subtypes C and E, respectively. Phylogenetic analysis revealed t hat the branching pattern based on the region was similar to that based on the env V3 to V5 region. Here, we propose a protocol to differentiate five subtypes by polymerase chain reaction amplifying 329 bp within the region f ollowed by restriction fragment-length polymorphism analysis using four res triction enzymes.