Perspective on Possible Recombination Event in Fusion Protein Gene of Newcastle Disease Viruses Isolated in Iran

Background and Aims: Newcastle disease (ND), caused by the virulent Newcastle disease virus (NDV), is one of the most important viral diseases in birds. In recent years recombination occurring throughout the NDVs genome isolated in China and Indonesia has been reported. This study was focused to investigate the recombination events in the F gene of the Iranian NDVs to generate useful data that can be applied in controlling programs. Materials and Methods: Sequences of 1200 base pairs of the F gene of Iranian NDVs were analyzed compared with the isolates from other reference strains. Divergence between the gene sequences and the influence of natural selection were estimated. The neutralizing epitopes and potential N-glycosylation sites within F proteins were determined. Possible recombination within the sequences was analyzed using RDP3 software. Results: Alignment and phylogenetic analysis based on the F gene revealed that Iranian NDVs share a higher nucleotide identity with NDVs representing genotype VII and further clustered into two sub-genotypes. The calculated Ka/Ks and negative Tajima’s D test indicate purifying/stabilizing selection. No recombination events were detected in F gene of Iranian NDV sequences deposited in GenBank. Conclusions: While no recombination event was identified for the gene, constant molecular and pathological characterization of circulating NDVs are needed to detect an evolutionary feature of the viruses.