Figure 4

Phylogenetic trees of the internal gene segments. Phylogenetic trees of the PB2, PB1, PA, NP, M and NS avian influenza virus gene segments are shown. The phylogeny was inferred using the Neighbor-Joining method. The evolutionary distances were computed using the Maximum Composite Likelihood method. The scale bars show the number of base substitutions per site. The NS scale is different due to the large distance between allele A and B. The green, blue, yellow and red squares represent Eurasian avian, Eurasian gull, American avian and American gull reference sequences, respectively [19]. The closed green and blue circles indicate Eurasian avian and Eurasian gull sequences obtained from GenBank, whereas the open green and blue circles are Eurasian avian and Eurasian gull sequences from this study (Additional file 2: Table S2).