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Phylogenetic trees of selected influenza virus H2 (a) and N3 (b) genes based on the nucleotide sequences of the ORFs. Horizontal distance is proportional to genetic distance. The trees are rooted to A/duck/Singapore/97 H5N3 (a) and A/tern/Astrakan/775/83 H3N3 (b). Numbers below nodes represent bootstrap values from 200 replicates.
