Results of BEAST analyses of test sequence data.

1See Methods and Supporting Information: Lists S1 and S2. OG, outgroup, CAb, CAbMV cCP sequences. PRS, PRSV cCP sequences. 2Root age. The mean tree root height as ‘years before present’ (YBP) calculated by BEAST given a prior substitution rate of 1.2×10−4 substitutions/site/year. 3Mid-tree age. The mean divergence (YBP) of all pairs of cCP sequences linked through the mid point of the tree estimated from the two most distant sequences. 4Species age. The mean divergence (YBP) of the American CAbMV (rows b and d) or PRSV (rows c and e) cCP sequences linked through the basal node of each cluster. 5NA, Not applicable.