Figure 2

Phylogeny of 60 influenza hemagglutinin nucleotide sequences from subtypes A-H3N2, B, and C. We reconstruct the phylogeny in (a) under a strict molecular clock via TREBLE [26]. The phylogeny in (b) is the same tree as in (a) with the divergence time between subtypes A and B recalibrated relaxing the molecular clock. (a) Without recalibration (b) With recalibration.