Genetic and phylogenetic analysis of the non-structural proteins NS1, NS2 and NS3 of epizootic haemorrhagic disease virus (EHDV)

Three unique non-structural (NS) proteins are produced by Epizootic haemorrhagic disease virus (EHDV) during infection of a host cell; NS1, NS2 and NS3. This study presents a complete genetic and phylogenetic analysis of these proteins (and the genes that code for them) to allow comparison of the selective pressures acting on each. Accession numbers, gene and protein sizes, ORF positions, G + C contents, terminal hexanucleotides, start and stop codons and phylogenetic relationships are all presented. Unlike the core, or outer-coat proteins, there are no characteristic genetic or phylogenetic traits common to all of the EHDV NS proteins; indicating that each is evolving under different selection pressures. These differences are discussed. Evidence of genetic recombination in genome segment 8 (coding for NS2) is also presented, together with evidence of gene duplication and mutation, suggesting the EHDV genome may have evolved using mechanisms such as these.