Fig. 2
From: The molecular determinants of antigenic drift in a novel avian influenza A (H9N2) variant virus
Sequence variation at the mutant sites in HA1 of H9N2 influenza A viruses. A Homotrimers of FJ/20 HA showing the amino acid difference between FJ/20 and AH/17. The mutations are shown as red with H9 numbering. B Maximum likelihood (ML) phylogeny of the H9N2 influenza virus HA amino acid sequence. The HA gene sequences from reference H9N2 viruses were downloaded from GISAID’s EpiFlu Database. The ML tree was constructed with the MEGA (7.0) software under the Jones–Taylor–Thornton (JTT) model with 1000 bootstraps. Vaccine strain AH/17 is in the red sub-clade. The blue sub-clade contains FJ/20. Amino-acid identity is shown by color, grouped by side-chain property, according to the legend