Figure 2.

Consensus maximum-likelihood phylogenetic tree constructed with sequences of the dengue virus type 4 (DENV-4) envelope protein gene. Genotypes are identified by roman numerals. Clades of genotype II are identified by the letters a–e. Sub-clade e.1 identifies the cluster where the 2010 Puerto Rican DENV-4 strains are located, and these strains are represented by black circles. Bayesian posterior probability (in italics) and bootstrapping values ≥ 80 are shown above and under the branch nodes, respectively. Branch lengths are proportional to the scale bar and the scale bar represent the number of nucleotide substitutions between the analyzed viruses. The tree is mid-point rooted.