Example simulation. Example of simulating a pair of correlated gene trees, with 0 < c < 1. (a) The dated species tree. (b) The first speciation happens at date 2. (c) A duplication occurs at date 1.42. This duplication only occurs in the left gene tree; the right child of the duplication is paired to the original branch in the right gene tree. (d) Another speciation happens at date 1. (e) A transfer occurs in both trees at date 0.55. (f) There are no further events and we reach the time of the leaves (date 0). (g) The resulting gene trees.