A provisional classification of cytoplasmic polyhedrosis viruses based on the sizes of the RNA genome segments.

The RNA genome segments of thirty-three isolates of cytoplasmic polyhedrosis viruses (CPVs) were examined by polyacrylamide gel electrophoresis. Major differences were observed in the gel profiles of the RNA segments from many of the viruses; differences which were reinforced by polyacrylamide gel electrophoresis of the virus structural proteins. As a result of these studies, a provisional classification scheme for CPVs is proposed, where viruses with similar RNA gel profiles are included within the same 'type', while isolates differing in the molecular weights of most, or all of the RNA segments are assigned to different types. Using this system, eleven distinct CPV types were recognized. All eleven CPV types, like reoviruses, probably contain ten segments of RNA with a toatl mol. wt. of approx. 15 X 10(6).