NUCLEOTIDE-SEQUENCES OF AUSTRALIAN ISOLATES OF THE FELINE IMMUNODEFICIENCY VIRUS - COMPARISON WITH OTHER FELINE LENTIVIRUSES

Proviral DNA from four Australian isolates of feline immunodeficiency virus (FIV) was amplified by PCR and the nucleotide sequence determine d for two conserved regions within gag (p 15/p 24) and pol (RT) genes. Comparison with the nucleotide and deduced amino acid sequence of two previously described U.S. isolates from California (Petaluma and PPR) , and a third from Maryland (MD) as well as the Japanese isolate TM 2, revealed a close similarity between the Australian and Californian is olates with 95-97% nucleotide and 96-99% amino acid homologies. By con trast, the Maryland and Japanese isolates were more distantly related with only 84-87% nucleotide and 90-94% amino acid homology with either the Australian or Californian isolates. The relationship of the Austr alian FIV isolates to other domestic isolates as well as eight lentivi ral isolates from wild felidae (panthers) published previously, was in vestigated further by constructing a phylogenetic tree based on the po l sequence. This revealed two subgroups of FIV, an Australian/Californ ian group and a less tightly clustered Maryland/Japanese group. These results suggest that the genomic variability of FIV is reflected by mo re than simply geographic distance. Furthermore, the relative genetic homogeneity found between Australian isolates suggest a shorter period of evolution of the virus in Australia than in North America.