Tree-based unrooted phylogenetic networks

Andrew Francis, Katharina Huber (Lead Author), Vincent Moulton

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)
15 Downloads (Pure)


Phylogenetic networks are a generalization of phylogenetic trees that are used to represent non-tree-like evolutionary histories that arise in organisms such as plants and bacteria, or uncertainty in evolutionary histories. An unrooted phylogenetic network on a non-empty, finite set X of taxa, or network, is a connected, simple graph in which every vertex has degree 1 or 3 and whose leaf set is X. It is called a phylogenetic tree if the underlying graph is a tree. In this paper we consider properties of tree-based networks, that is, networks that can be constructed by adding edges into a phylogenetic tree. We show that although they have some properties in common with their rooted analogues which have recently drawn much attention in the literature, they have some striking differences in terms of both their structural and computational properties. We expect that our results could eventually have applications to, for example, detecting horizontal gene transfer or hybridization which are important factors in the evolution of many organisms.

Correction available at
Original languageEnglish
Pages (from-to)404–416
Number of pages13
JournalBulletin of Mathematical Biology
Issue number2
Early online date13 Dec 2017
Publication statusPublished - Feb 2018


  • phylogenetic tree
  • phylogenetic network
  • Tree-based network
  • Hamiltonian path

Cite this