Figure 1.

Consensus maximum-likelihood phylogenetic tree constructed with sequences of the dengue virus type 1 (DENV-1) envelope protein gene. Genotypes are identified by roman numerals. Clades of genotype V are identified by the letters a–e. Strains collected from blood donors from Puerto Rico are represented by black circles and the strain from Key West, Florida, are represented by a black square. 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 represents number of nucleotide substitutions between the analyzed viruses. The tree is mid-point rooted.