Abstract
The DNA polymerase from Amherst pheasant virus (APV), a member of the pheasant virus species of retroviruses, was compared to the DNA polymerases of avian leukosis viruses (ALV) and a reticuloendotheliosis virus (spleen necrosis virus [SNV]). Immunoglobulin inhibition tests and competition immunoassays showed that APV and ALV DNA polymerases are closely related to their active sites. The determinants common to their active sites are not shared by SNV DNA polymerase. By using a species-specific radioimmunoassay, it was shown that APV and SNV DNA polymerases are grossly different from ALV DNA polymerase. The specificity of the relationship of the active sites of APV and ALV DNA polymerases was confirmed by a heterlogous radioimmunoassay. The data indicate that pheasant viruses are evolutionarily linked to ALV.