Figure 2.

Positions of the ZIKV strains for the first two major axes of principal component analysis of the (a) dinucleotide observed/expected ratios, (b) relative synonymous codon usage, and (c) amino acid frequencies. The proportion of variance explained by each axis is displayed, placed between parentheses. Strains in the plot are colored according to their clade assignment depicted in Figure 1 (i.e., in blue, red, green, violet, and black).