Fig. 3
From: The molecular determinants of antigenic drift in a novel avian influenza A (H9N2) variant virus
Schematic diagram of AH/17 and FJ/20 chimeras and mutants. A Amino acid substitutions in four chimeric viruses. Four types of chimeras were divided and grouped according to the position of different amino acids on the surface of HA protein. B Schematic illustration of the rescued chimeras and mutants by reverse genetics. Amino acid substitutions were introduced into the AH/17 and FJ/20 HA genes by PCR-based site-directed mutagenesis and viruses were generated by 6:2 reverse genetics system