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Distinguishing between convergent evolution and violation of the molecular clock for three taxa
journal contribution
posted on 2023-05-19, 19:13 authored by Jonathan MitchellJonathan Mitchell, Jeremy SumnerJeremy Sumner, Barbara HollandBarbara HollandWe give a non-technical introduction to convergence–divergence models, a new modeling approach for phylogenetic data that allows for the usual divergence of lineages after lineage-splitting but also allows for taxa to converge, i.e. become more similar over time. By examining the 3-taxon case in some detail, we illustrate that phylogeneticists have been “spoiled” in the sense of not having to think about the structural parameters in their models by virtue of the strong assumption that evolution is tree-like. We show that there are not always good statistical reasons to prefer the usual class of tree-like models over more general convergence–divergence models. Specifically, we show many 3-taxon data sets can be equally well explained by supposing violation of the molecular clock due to change in the rate of evolution along different edges, or by keeping the assumption of a constant rate of evolution but instead assuming that evolution is not a purely divergent process. Given the abundance of evidence that evolution is not strictly tree-like, our discussion is an illustration that as phylogeneticists we need to think clearly about the structural form of the models we use. For cases with four taxa, we show that there will be far greater ability to distinguish models with convergence from non-clock-like tree models.
Funding
Australian Research Council
History
Publication title
Systematic BiologyVolume
67Issue
5Pagination
905-915ISSN
1063-5157Department/School
School of Natural SciencesPublisher
Taylor & Francis IncPlace of publication
325 Chestnut St, Suite 800, Philadelphia, USA, Pa, 19106Rights statement
Copyright 2018 The AuthorsRepository Status
- Restricted