Publication

Inferring ancestral states without assuming neutrality or gradualism using a stable model of continuous character evolution

Elliot, M. G. & Mooers, A. O., 28-Nov-2014, In : BMC Evolutionary Biology. 14, 15 p., 226.

Research output: Contribution to journalArticleAcademicpeer-review

Background: The 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).

Results: We 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.

Conclusions: The 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.

Original languageEnglish
Article number226
Number of pages15
JournalBMC Evolutionary Biology
Volume14
Publication statusPublished - 28-Nov-2014
Externally publishedYes

    Keywords

  • Comparative methods, Ancestral state reconstruction, Evolutionary models, SQUARED-CHANGE PARSIMONY, PHYLOGENETIC ANALYSIS, BODY-SIZE, INDEPENDENT CONTRASTS, STABILIZING SELECTION, ADAPTATION, LIKELIHOOD, RECONSTRUCTION, DISTRIBUTIONS, MAMMALS

ID: 76751386