MaxTiC: Fast Ranking Of A Phylogenetic Tree By Maximum Time Consistency With Lateral Gene Transfers
Résumé
Lateral gene transfers between ancient species contain information about the relative timing of species diversification. Specifically, the ancestors of a donor species must have existed before the descendants of the recipient species. Hence, the detection of a transfer event can be translated into a time constraint between nodes of a phylogeny if the donor and recipient can be identified. When a set of transfers are detected by interpreting the phylogenetic discordance between gene trees and a species tree, the set of all deduced time constraints can be used to rank the species tree, i.e. order totally its internal nodes. Unfortunately lateral gene transfer detection is challenging and current methods produce a significant proportion of false positives. As a result a set of time constraints deduced from predicted transfers is not always compatible with any ranking of the species tree. We propose a method, implemented in a software called MaxTiC (Maximum Time Consistency), which takes as input a species tree and a series of possibly inconsistent time constraints between its internal nodes, weighted by confidence scores. MaxTiC outputs a ranked species tree compatible with a subset of constraints with maximum confidence score sum. We extensively test the method on simulated datasets, under a wide range of conditions that we compare to measures on biological datasets. In most conditions the obtained ranked tree is very close to the real one, confirming the theoretical possibility of dating the history of life with transfers by maximizing time consistency. MaxTiC is available with a documentation and several examples described in this article: https://github.com/ssolo/ALE/tree/master/maxtic.
Domaines
Bio-informatique [q-bio.QM]
Origine : Fichiers produits par l'(les) auteur(s)
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