Phylogeny of G9 rotavirus genotype: a possible explanation of its origin and evolution

G9 rotavirus genotype was isolated in the 1980s and re-emerged without a clear explanation in the mid-1990s as one of the most frequently occurring genotypes with distinct genetic and molecular characteristics.

To study the G9 genotype sequence polymorphisms in Spain and compare them with the human and porcine G9 VP7 genes from the rest of the world. Complete phylogenetic analyses have been done to better characterize G9 genotypes, their relationships and evolution.

Twelve G9 VP7 genes from Spanish patients were sequenced and compared with 240 G genotype sequences. Nucleotide and amino acid sequence similarity percentages and neighbour-joining dendrograms were used to establish a new phylogenetic analysis.

Eight of the 12 Spanish sequenced samples had different nucleotide translated region sequences, which yielded only five different proteins. New nucleotide and amino acid sequence comparisons were made that differed from previously described results.

Spanish G9 genotype sequences have similar structure of those belonging to lineage III as the majority of the G9 sequences and share amino acid motifs with other sequences. The phylogenetic analyses of G9 genotypes confirmed the existence of 6 lineages, but did not confirm the 11 sublineages previously reported.