Fig 8. rNNI moves around the different types of internal arcs.

For each type (BB, RR, BR, RB), we list the networks that can be obtained by performing an rNNI around that an arc of that type. The four types of arc are named on the basis of u and v being a bifurcation (B) or a reticulation (R). If some of the vertices in the drawing are not distinct (e.g., if α = γ in a move of type RR), or if a γ-β path exists in a move of type BR, then some of the moves above may not be applicable. See the proof of Proposition 2 (in the S1 Text) for details.