Abstract
To examine the possibility of past intragenic recombination events in rotaviruses, 207 VP7 gene sequences were collected from the international DNA databanks (DDBJ/EMBL/GenBank) and subjected to the molecular evolutionary analyses. In the phylogenetic tree reconstructed, two strains (CH55 and CHW17) bearing the G3 serotype made a cluster with G1 strains, but not with other G3 strains. By conducting statistical analyses, we found that the VP7 genes of those strains had the mosaic structure of G1 and G3 sequences. As a result, we concluded that the intragenic recombination may be one of the escaping mechanisms from the host immune system in rotaviruses. This process contributes to production of antigenic variation, thus implying the limited effectiveness of multivalent vaccines for the prevention of rotavirus infection.