Abstract
Detailed structural studies were undertaken on five isolates of bovine rotavirus which showed variability in the migration patterns of their genome segments on electrophoresis in polyacrylamide gels. The individual genome segments of each isolate were characterized by partial digestion of terminally radiolabeled RNA with a base-specific nuclease. This analysis showed that whereas mobility variations were always associated with detectable changes in nucleotide sequence, sequence changes at least as great as those found in segments showing electrophoretic mobility variations were also detected in segments showing no mobility variation. Evidence for the occurrence of genome segment reassortment between viruses in the field was obtained from analyzing the species 11 RNAs from these five isolates. The overall conclusion from these results is that great care is required in the interpretation of simple genome profile analysis of different isolates for epidemiological purposes and that classification of these viruses solely on the basis of genome electropherotype could be misleading.