Chicken rotavirus Ch-1 shows a second type of avian VP6 gene.

VP6 protein from chicken rotavirus Ch-1 showed more than 13% amino acid differences in comparison with pigeon and turkey VP6 sequences. This difference is greater than that observed between subgroup I and II mammalian rotavirus VP6 sequences. Phylogenetic tree analysis demonstrated that RV Ch-1 VP6 is not a link between avian and mammalian VP6 sequences. RV Ch-1 showed variant aa in 17 positions which were otherwise absolutely conserved in mammalian and avian group A RVs. The 17 replacements were scattered through the entire VP6 sequence except the C-terminal part implicated in the assembly of subviral particles. In RV Ch-1 the proline residue 309, reported to be critical for the trimerization of VP6, was replaced by leucine, but VP6 trimers were still observed. The sequence and hydrophilicity analysis of avian RV VP6 do not explain the anomalous electrophoretic migration behavior of avian VP6 proteins.