Comparative analysis estimates the relative frequencies of co-divergence and cross-species transmission within viral families (original) (raw)
Fig 1
Tanglegrams of phylogenetic trees created using simulated data.
Lines connect the virus with its respective host. Hence, if viruses and hosts have congruent phylogenies—indicative of strong virus-host co-divergence—then there will obviously be more horizontal than diagonal lines. Panel (A) illustrates a perfectly matched topology between virus and host trees and thus the nPH85 = 0. Panel (B) exemplifies an entirely mismatched topology between virus and host trees, where the nPH85 = 1. Data from viruses in nature will fall between these two extremes. Panels (C) and (D) illustrate two examples where the host trees have one incongruent node. Panel (C) corresponds to a shallower section of the tree than in panel (D), but the two nPH85 are the same, such that the position of the incongruence does not produce a systematic bias. Panel (E) elucidates the relationship between the nPH85 distance and the number of incongruent nodes between a pair of simulated trees with 100 tips.