Extended Data Figure 6. Maximum clade credibility (MCC) tree summaries of Bayesian spatio-temporal reconstruction comparing early and late strains (a: “env 133”, b: only “late” sequences from “env 133”).

In a), we classified US sequences as ‘early’ or ‘late’ depending on whether they were sampled before or after (and including) 1985. In b), the analysis was conducted on an empirical tree distribution of “env 133” from which we pruned early US sequences (in grey), but we still annotate the reconstruction on the complete phylogenies for reference. The tips of the tree correspond to the year of sampling while the branch (and node) colours reflect location: the sampling location for the tip branches and the inferred location for the internal branches (AF, Africa; CB, Caribbean; US early, the United States sampled < 1985; US late, the United States sampled in or after 1985; CA, California; GA, Georgia; NC, North Carolina, NY, New York). The diameters of the internal node circles reflect posterior location probability values. Thick outer circles represent internal nodes with posterior probability support > 0.95.