FIG. 2.

Same analysis as in Fig. 1, presented in segment-by-segment fashion for all eight influenza virus segments. Blue asterisks represent human H1N1 strains, purple squares represent H5N1 found in humans, and red pluses represent the remaining human strains available from the NCBI database. Green crosses represent all the avian strains available in the NCBI database at the time of analysis. HA, hemagglutinin gene; NA, neuraminidase gene. PB1, PB2, and PA, the three viral polymerase subunits; NP, nucleoprotein; MP, matrix protein; NS, nonstructural.