Planar Phylogenetic Networks

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A phylogenetic network is a rooted, directed acyclic graph, with a single root, whose sinks correspond to a set of species. Such networks are commonly used to represent the evolution of species that have undergone reticulate evolution. Recently, there has been great interest in developing the theory behind and algorithms for constructing such networks. One issue with phylogenetic networks is that, unlike rooted evolutionary trees, they can be highly non-planar (i.e. it is not possible to draw them in the plane without some arcs crossing). This can make them difficult to visualise and interpret. In this paper we investigate properties of planar phylogenetic networks and algorithms for deciding whether or not phylogenetic networks have certain special planarity properties. In particular, as well as defining some natural subclasses of planar phylogenetic networks and working out their interrelationships, we characterize when the well-known level-k networks are planar as well as showing that planar regular networks are closely related to pyramids. Our results make use of the highly developed field of planar digraphs, and we believe that the link between phylogenetic networks and this field should prove useful in future for developing new approaches to both construct and visualise phylogenetic networks.
Original languageEnglish
JournalIEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication statusAccepted/In press - 6 Jun 2022

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