Genetic relatedness among animal rotaviruses

The genomic relatedness among representative rotavirus strains was examined by employing cross-hybridization techniques. Single stranded (ss) RNA prepared by in vitro transcription of purified rotavirus particles and labeled with either 32P or 125I was hybridized to denatured genomic, double stranded (ds) RNAs. The hybrids formed were analyzed by polyacrylamide gel electrophoresis (PAGE) or by testing their sensitivity to digestion with single strand specific nuclease (S-1 nuclease). A relatively high degree of genomic homology was found to exist among several bovine rotavirus strains obtained from different geographical areas. Similarly, a high degree of homology was found between two different simian rotavirus strains, and also between two porcine strains. The human Wa strain exhibited a low degree of genomic homology with simian, bovine and canine strains whereas a higher level of homology was detected between the human Wa strain and the porcine strains. The observed RNA sequence divergences of rotaviruses isolated from different animal species are in agreement with the restricted host range of these viruses and their known antigenic differences and suggest a divergent evolution of their genomes.