Phylogenetic tree of HA for HA-NA available strains of A/H1N1 virus.

Abstract

<p>The phylogenetic tree was constructed using 998 complete HA-coding nucleotide sequences for HA-NA available strains of A/H1N1 virus. Cluster I and II correspond to those in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040422#pone.0040422.s002" target="_blank">Figure S2</a>. (A) The strain names at exterior nodes were colored according to the net-charge in HA1; red: +14-+16, pink: +12-+13, orange: +10-+11, yellow: +8-+9, right blue: +6-+7, and blue: +4-+5. (B) The strain names at exterior nodes were colored red or orange when they had triple (Gln222, Met234, and Tyr274) or single (Tyr274) amino acid mutation in NA, respectively.</p