Triples with duplication event at the root. Triples from T whose root is a duplication event are in general not displayed from the species tree S. (a) Triple with duplication event at the root obtained from the true evolutionary history of T shown in panel (b). Panel (c) is the true species tree. In the triple (a) the species y appears as the outgroup even though the x is the outgroup in the true species tree.
Hernandez-Rosales et al. BMC Bioinformatics 2012 13(Suppl 19):S6 doi:10.1186/1471-2105-13-S19-S6