Figure 4. Schematic illustration of the reassortment process of avian influenza viruses in poultry from live poultry markets of Zheijang Province, eastern China.

The H9N2 avian influenza viruses donated internal genes to other viruses. The eight gene segments (from top to bottom) in each virus are PB2, PB1, PA, HA, NP, NA, M, and NS. Each color represents a separate virus background. The simplified schematic illustration is based on nucleotide-distance comparison and phylogenetic analysis. The arrows indicate subtypes of avian influenza viruses that can cause human infection.