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Stéphane Guindon (computational Evolution, Auckland, NZ)

Salle de formation du PRABI

par Vincent Daubin - 10 juillet 2014

Modelling competition and dispersal in a statistical phylogeographic framework

Competition between organisms influences the processes governing the colonization of new
habitats. As a consequence, species or populations arriving first at a suitable location may prevent
secondary colonization. While adaptation to environmental variables (e.g., temperature, altitude,
etc.) is essential, the presence or absence of certain species at a particular location often
depends on whether or not competing species co-occur. For example, competition is thought to play an important
role in structuring mammalian communities assembly. It can also explain spatial patterns of low
genetic diversity following rapid colonization events or the ``progression rule’’ displayed by
phylogenies of species found on archipelagos. Despite the potential of competition to maintain
populations in isolation, past quantitative analyses have largely ignored it because of the
difficulty in designing adequate methods for assessing its impact. We present here a new model that
integrates competition and dispersal into a Bayesian phylogeographic framework. Extensive
simulations and analysis of real data show that our approach clearly outperforms the traditional
Mantel test for detecting correlation between genetic and geographic distances. But most
importantly, we demonstrate that competition can be detected with high sensitivity and specificity
from the phylogenetic analysis of genetic variation in space.

Joint work with L. Ranjard, D. Welch and M. Paturel.

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