Fig 3. Tip-labelled maximum clade credibility phylogenetic tree reconstructed from 246 nationally distributed WNV genomes.

Each tip consists of the accession number, vector or host where the strain was derived, two letter state code (or 4 letter code for location in Mexico), and the date of sampling to the nearest hundredth of a year. The gradient squares indicates the phylogenetic position of the NY99 (blue), NA/WN02 (red), and SW/WN03 (orange) genotypes. NA/WN02 and SW/WN03 strains are defined by the E-V195A substitution and the SW/WN03 genotype is defined by the NS4A-A85T substitution. Clade-defining substitutions, as well as convergent substitutions, are denoted by stars. Posterior probabilities are represented by the size (larger circles have higher values) and color (defined by the color legend) of circles at each node.