Inferring Ancestral States without Assuming Neutrality or Gradualism Using a Stable Model of Continuous Character Evolution

Resource type
Date created
2014
Authors/Contributors
Author: Mooers, Arne
Abstract
BackgroundThe value of a continuous character evolving on a phylogenetic tree is commonly modelled as the location of a particle moving under one-dimensional Brownian motion with constant rate. The Brownian motion model is best suited to characters evolving under neutral drift or tracking an optimum that drifts neutrally. We present a generalization of the Brownian motion model which relaxes assumptions of neutrality and gradualism by considering increments to evolving characters to be drawn from a heavy-tailed stable distribution (of which the normal distribution is a specialized form).ResultsWe describe Markov chain Monte Carlo methods for fitting the model to biological data paying special attention to ancestral state reconstruction, and study the performance of the model in comparison with a selection of existing comparative methods, using both simulated data and a database of body mass in 1,679 mammalian species. We discuss hypothesis testing and model selection. The stable model outperforms Brownian and Ornstein-Uhlenbeck approaches under simulations in which traits evolve with occasional large “jumps” in their value, but does not perform markedly worse for traits evolving under a truly Brownian process.ConclusionsThe stable model is well suited to a stochastic process with a volatile rate of change in which biological characters undergo a mixture of neutral drift and occasional evolutionary events of large magnitude.
Document
Published as
BMC Evolutionary Biology 2014, 14:226 doi:10.1186/s12862-014-0226-8
Publication title
BMC Evolutionary Biology
Document title
Inferring Ancestral States without Assuming Neutrality or Gradualism Using a Stable Model of Continuous Character Evolution
Date
2014
Volume
14
Publisher DOI
10.1186/s12862-014-0226-8
Copyright statement
Copyright is held by the author(s).
Scholarly level
Peer reviewed?
Yes
Language
Member of collection
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s12862-014-0226-8.pdf 653.55 KB