Diversity and prevalence of influenza A(H5N6) viruses isolated from humans, China. Circles represent the corresponding virus genotypes and their times of isolation. Gene segments are ordered as polymerase basic 2, polymerase basic 1, polymerase acidic, hemagglutinin, nucleoprotein, neuraminidase, matrix, and nonstructural from top to bottom within circles. A total of 13 genotypes are listed; the genotype name is shown under each circle. Names of each human H5N6 virus are listed besides the genotype to which they belong. To illustrate the history of reassortant events, segments in descendant viruses are colored according to their corresponding source viruses on the bottom line.