Figure 1.

Phylogenetic tree of the nucleotide sequences of full S1 gene of Egyptian IBVs. Phylogenetic analysis was based on genotype classification of the S1 gene [7]. Maximum likelihood calculations were done using the IQTree software under the best fit model (TIM3 + F + I + G4) according to the Bayesian criterion. Egyptian IBVs were colored based on the genotype (purple = GI-1, brown = GI-13, green = GI-16, and red = GI-23). Vaccine strains used in Egypt are shown in the blue box. The strain names, locations, and accession numbers of different lineages are fully described in Valastro et al. 2016 [7].