Exploring the Tiers of Rooted Phylogenetic Network Space Using Tail Moves

Remie Janssen (1) , Mark Jones (1) , Péter Erdős (2) , Leo van Iersel (1) , Celine Scornavacca (3, 4)

1 DIAM - Delft Institute of Applied Mathematics
2 Alfréd Rényi Institute of Mathematics
3 UMR ISEM - Institut des Sciences de l'Evolution de Montpellier
4 IBC - Institut de Biologie Computationnelle

Popular methods for exploring the space of rooted phylogenetic trees use rearrangement moves such as rooted Nearest Neighbour Interchange (rNNI) and rooted Subtree Prune and Regraft (rSPR). Recently, these moves were generalized to rooted phylogenetic networks, which are a more suitable representation of reticulate evolutionary histories, and it was shown that any two rooted phylogenetic networks of the same complexity are connected by a sequence of either rSPR or rNNI moves. Here, we show that this is possible using only tail moves, which are a restricted version of rSPR moves on networks that are more closely related to rSPR moves on trees. The connectedness still holds even when we restrict to distance-1 tail moves (a localized version of tail moves). Moreover, we give bounds on the number of (distance-1) tail moves necessary to turn one network into another, which in turn yield new bounds for rSPR, rNNI and SPR (i.e. the equivalent of rSPR on unrooted networks). The upper bounds are constructive, meaning that we can actually find a sequence with at most this length for any pair of networks. Finally, we show that finding a shortest sequence of tail or rSPR moves is NP-hard.

Mots clés: Tail-move operation; Rearrangement; Diameter; Head-move operation; Network space; Phylogenetic network

Domaines: Informatique [cs]; Bio-informatique [q-bio.QM]; Mathématique discrète [cs.DM]

Remie Janssen, Mark Jones, Péter Erdős, Leo van Iersel, Celine Scornavacca. Exploring the Tiers of Rooted Phylogenetic Network Space Using Tail Moves. Bulletin of Mathematical Biology, 2018, 80 (8), pp.2177-2208. ⟨10.1007/s11538-018-0452-0⟩. ⟨hal-02154852⟩