Fig. 8.

Conditional probabilities of ranked and unranked anomaly zones given species tree shape for all possible six-taxon unlabeled, unranked species tree topologies. The exact probabilities of tree shapes under the Yule birth process are displayed on the x-axis. The results are based on 5,000 species trees simulated under the birth process with n = 6, $\lambda =0.5$, and μ = 0. Among the shapes with both AGTs and ARGTs, the third tree shape, with four taxa descended from one side of the root and two from the other, produces the largest combined frequency of AGTs and ARGTs. It is also the most probable shape under the birth process. Similar patterns occur for $\lambda =0.1$ and λ = 1 (not shown).