Long-branch attraction bias and inconsistency in Bayesian phylogenetics.

Bayesian inference (BI) of phylogenetic relationships uses the same probabilistic models of evolution as its precursor maximum likelihood (ML), so BI has generally been assumed to share ML's desirable statistical properties, such as largely unbiased inference of topology given an accurate model...

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Main Authors: Bryan Kolaczkowski, Joseph W Thornton
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2009-12-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC2785476?pdf=render
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author Bryan Kolaczkowski
Joseph W Thornton
author_facet Bryan Kolaczkowski
Joseph W Thornton
author_sort Bryan Kolaczkowski
collection DOAJ
description Bayesian inference (BI) of phylogenetic relationships uses the same probabilistic models of evolution as its precursor maximum likelihood (ML), so BI has generally been assumed to share ML's desirable statistical properties, such as largely unbiased inference of topology given an accurate model and increasingly reliable inferences as the amount of data increases. Here we show that BI, unlike ML, is biased in favor of topologies that group long branches together, even when the true model and prior distributions of evolutionary parameters over a group of phylogenies are known. Using experimental simulation studies and numerical and mathematical analyses, we show that this bias becomes more severe as more data are analyzed, causing BI to infer an incorrect tree as the maximum a posteriori phylogeny with asymptotically high support as sequence length approaches infinity. BI's long branch attraction bias is relatively weak when the true model is simple but becomes pronounced when sequence sites evolve heterogeneously, even when this complexity is incorporated in the model. This bias--which is apparent under both controlled simulation conditions and in analyses of empirical sequence data--also makes BI less efficient and less robust to the use of an incorrect evolutionary model than ML. Surprisingly, BI's bias is caused by one of the method's stated advantages--that it incorporates uncertainty about branch lengths by integrating over a distribution of possible values instead of estimating them from the data, as ML does. Our findings suggest that trees inferred using BI should be interpreted with caution and that ML may be a more reliable framework for modern phylogenetic analysis.
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spelling doaj.art-9e02c5a751224b5da76cc63d92373a8e2022-12-21T19:56:40ZengPublic Library of Science (PLoS)PLoS ONE1932-62032009-12-01412e789110.1371/journal.pone.0007891Long-branch attraction bias and inconsistency in Bayesian phylogenetics.Bryan KolaczkowskiJoseph W ThorntonBayesian inference (BI) of phylogenetic relationships uses the same probabilistic models of evolution as its precursor maximum likelihood (ML), so BI has generally been assumed to share ML's desirable statistical properties, such as largely unbiased inference of topology given an accurate model and increasingly reliable inferences as the amount of data increases. Here we show that BI, unlike ML, is biased in favor of topologies that group long branches together, even when the true model and prior distributions of evolutionary parameters over a group of phylogenies are known. Using experimental simulation studies and numerical and mathematical analyses, we show that this bias becomes more severe as more data are analyzed, causing BI to infer an incorrect tree as the maximum a posteriori phylogeny with asymptotically high support as sequence length approaches infinity. BI's long branch attraction bias is relatively weak when the true model is simple but becomes pronounced when sequence sites evolve heterogeneously, even when this complexity is incorporated in the model. This bias--which is apparent under both controlled simulation conditions and in analyses of empirical sequence data--also makes BI less efficient and less robust to the use of an incorrect evolutionary model than ML. Surprisingly, BI's bias is caused by one of the method's stated advantages--that it incorporates uncertainty about branch lengths by integrating over a distribution of possible values instead of estimating them from the data, as ML does. Our findings suggest that trees inferred using BI should be interpreted with caution and that ML may be a more reliable framework for modern phylogenetic analysis.http://europepmc.org/articles/PMC2785476?pdf=render
spellingShingle Bryan Kolaczkowski
Joseph W Thornton
Long-branch attraction bias and inconsistency in Bayesian phylogenetics.
PLoS ONE
title Long-branch attraction bias and inconsistency in Bayesian phylogenetics.
title_full Long-branch attraction bias and inconsistency in Bayesian phylogenetics.
title_fullStr Long-branch attraction bias and inconsistency in Bayesian phylogenetics.
title_full_unstemmed Long-branch attraction bias and inconsistency in Bayesian phylogenetics.
title_short Long-branch attraction bias and inconsistency in Bayesian phylogenetics.
title_sort long branch attraction bias and inconsistency in bayesian phylogenetics
url http://europepmc.org/articles/PMC2785476?pdf=render
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