Not all phylogenetic networks are leaf-reconstructible

Abstract

Unrooted phylogenetic networks are graphs used to represent evolutionary relationships. Accurately reconstructing such networks is of great relevance for evolutionary biology. It has recently been conjectured that all phylogenetic networks with at least five leaves can be uniquely reconstructed from their subnetworks obtained by deleting a single leaf and suppressing degree-2 vertices. Here, we show that this conjecture is false, by presenting a counter example for each possible number of leaves that is at least~4. Moreover, we show that the conjecture is still false when restricted to binary networks.