Figure 3. Representation of the posterior probability densities obtained when dating the most recent common ancestor of the Old World and New World begomoviruses using GRD integration times inferred from (A) the dated Nicotiana phylogeny (“Nicotiana phylogeny approach”) or (B) the estimated time till the most recent common ancestor of the integrated GRD sequences using the neutral substitution rate of Nicotiana ITS nrDNA sequences (“Neutral rate approach”).

Probability densities obtained with the median, upper 95% HPD limit and lower 95% HPD limit of estimated integration times using two different methods are represented by blue, yellow and purple colours respectively. Vertical dotted lines indicate the median estimated date of each estimate. The grey area represents the time interval during which the genus Bemisia originated. The vertical dashed line indicates the point during the Earth's history when global cooling closed the then expansive Beringian land bridge as a pathway permitting the dispersal of tropical plant and animal species between Asia and North America.