Uma bordagem bayesiana na avaliação do impacto de eventos históricos nas taxas de diversificação

A Bayesian approach for evaluating the impact of historical events on rates of diversification

1. Brian R. Moorea,1 and
2. Michael J. Donoghueb,1
Contributed by Michael J. Donoghue, November 29, 2008 (sent for review June 22, 2008)

Evolutionary biologists often wish to explore the impact of a particular historical event (e.g., the origin of a novel morphological trait, an episode of biogeographic dispersal, or the onset of an ecological association) on rates of diversification (speciation minus extinction). We describe a Bayesian approach for evaluating the correlation between such events and differential rates of diversification that relies on cross-validation predictive densities. This approach exploits estimates of the marginal posterior probability for the rate of diversification (in the unaffected part of the tree) and the marginal probability for the timing of the event to generate a predictive distribution of species diversity that would be expected had the event not occurred. The realized species diversity can then be compared to this predictive diversity distribution to assess whether rates of diversification associated with the event are significantly higher or lower than expected. Although simple, this Bayesian approach provides a robust inference framework that accommodates various sources of uncertainty, including error associated with estimates of divergence times, diversification-rate parameters, and event history. Furthermore, the proposed approach is relatively flexible, allowing exploration of various types of events (including changes in discrete morphological traits, episodes of biogeographic movement, etc.) under both hypothesis-testing and data-exploration inference scenarios. Importantly, the cross-validation predictive densities approach facilitates evaluation of both replicated and unique historical events. We demonstrate this approach with empirical examples concerning the impact of morphological and biogeographic events on rates of diversification in Adoxaceae and Lupinus, respectively.

Footnotes

1To whom correspondence may be addressed. E-mail:brian.moore@berkeley.edu or michael.donoghue@yale.edu

Author contributions: B.R.M. and M.J.D. designed research; B.R.M. performed research; B.R.M. analyzed data; and B.R.M. and M.J.D. wrote the paper.

The authors declare no conflict of interest.
Freely available online through the PNAS open access option.
© 2009 by The National Academy of Sciences of the USA

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