Phylodynamics of CHIKV Asian genotype epidemics.

<p>Time-scaled maximum clade credibility (MCC) tree of the CHIKV Asian genotype was inferred by Bayesian analysis. Sequences from different regions are colored as described in the key. The Caribbean outbreak (CO) clade is supported by Bayesian posterior probabilities (BPP) as 1 in BMCMC analysis and bootstrap values 96% in the maximum likelihood phylogeny. Subclades CO1 and CO2, supported by BPP over 0.98, are also marked in the tree. A small group of Nicaraguan sequences that are relatively distinct from other Nicaraguan sequences are highlighted by a red hash symbol (#). The major ancestral geographic states (state probabilities over 0.5) at the backbone of phylogenetic tree are colored by region and labeled in the tree. The nodes with state probabilities greater than 0.9 are marked by asterisks. The mean and 95% highest posterior density (HPD) of the most recent common ancestor (tMRCA) of the entire Asian genotype and tMRCAs of virus movement between regions are also indicated. The scale bar represents chronological time (in years).