A non exchangeable coalescent arising in phylogenetics
August 5, 2015
A popular line of research in evolutionary biology is to use time-calibrated phylogenies in order to infer the underlying diversification process. This involves the use of stochastic models of ultrametric trees, i.e., trees whose tips lie at the same distance from the root. We recast some well-known models of ultrametric trees (infinite regular trees, exchangeable coalescents, coalescent point processes) in the framework of so-called comb metric spaces and give some applications of coalescent point processes to the phylogeny of bird species. However, these models of diversification assume that species are exchangeable particles, and this always leads to the same (Yule) tree shape in distribution. Here, we propose a non-exchangeable, individual-based, point mutation model of diversification, where interspecific pairwise competition is only felt from the part of individuals belonging to younger species. As the initial (meta)population size grows to infinity, the properly rescaled dynamics of species lineages converge to a one-parameter family of coalescent trees interpolating between the caterpillar tree and the Kingman coalescent. Recording during the thematic meeting: "Probability and biological evolution" the June 17, 2015 at the Centre International de Rencontres Mathématiques (Marseille, France)
Alice and the Enigmatic Tree of Rabbits
July 5, 2015
Wonderland is far away, and the white rabbit is sad: its phylogenetic tree is unbalanced, and he is very isolated at the end of its branch! Hopefully, Alice is here, and ready to help him disentangle the factors responsible for macroevolutionary patterns of species diversification!
Amaury at the Ernest
February 13, 2015
(Movie in French) Amaury Lambert explique les grands principes qui guident les travaux actuels dans le domaine de la modélisation mathématique de l'évolution du vivant.
Prédire le passé : Évolution, hasard et mathématiques
September 9, 2014
Entretien avec Amaury Lambert, chercheur au Centre Interdisciplinaire de Recherche en Biologie.