Figure 9.

Maximum Likelihood tree of DENV-4 based on envelope sequences (n = 1000). DENV-4 samples were collected from 16 countries across three regions of Asia, with a maximum number of 20 sequences per year included in the analysis. The nucleotide sequences were aligned using MAFFT v.7 and a phylogenetic tree was constructed in IQ-TREE v.2.2.2.6 using the GTR + F + I + R6 model with 1000 ultrafast bootstrap replicates. Bootstrap values are shown at the tree branches. Each terminal node is colored according to the country of origin. Locations, genotypes, and sampling years are shown in the legend. The scale bar represents the substitution rate per site. The panel on the right shows genotypes and ranges in sampling years corresponding to each taxon. Clades and groups (IIA and IIB) are indicated adjacent to the key branches, with colors corresponding to each genotype.