Figure 2

Sample evolutionary networks. Two evolutionary networks N₁ and N₂, each with eight leaves (labeled A,..., H) and two network nodes X and Y. Shown are the orientation of the network edges; all other edges are directed away from the root (toward the leaves) Notice that the difference between the two networks is that node X in N₁ has lineage G as one of its parents, whereas node X in N₂ has lineage H as one of its parents.