Evolutionary Dynamics and Emergence of Panzootic H5N1 Influenza Viruses
Virus particles outlined in black represent donor viruses (with mean TMRCAs above the particle) and those outlined in red represent characterized H5N1 genotypes placed at the year of first detection. Gene segments are ordered PB2, PB1, PA, HA, NP, NA, M and NS from top to bottom within the virus particle diagram. Arrows represent possible reassortment pathways of genotype development. The start of the black arrows (filled circles) indicate the earliest possible time of corresponding genotype generation. Colored arrows represent reassortment between existing H5N1 genotypes.