FIG 5.

Possible evolutionary pathways toward the generation of clade 2.3.4.4 HPAI H5N2/N6/N8 viruses and the diverse genotypes of HPAI H5N6 viruses. Virus particles are represented by colored ovals containing horizontal bars that represent the eight gene segments (from top to bottom: PB2, PB1, PA, HA, NP, NA, M, and NS). Segments in descendant viruses are colored according to their corresponding source viruses (top) to illustrate gene ancestry through reassortment events. Source viruses for a reassortment are adjacent to arrow tails; arrowheads point to the resulting reassortants. A broken bar in segment 6 (NA) indicates a stalk region deletion. The timeline on the left indicates the possible time of virus emergence or reassortment events.