Camille Coron

Quantifying the Mutational Meltdown in Diploid Populations

Mutational meltdown, in which demographic and genetic processes mutually reinforce one another to accelerate the extinction of small populations, has been poorly quantified despite its potential importance in conservation biology. Here we present a model-based framework to study and quantify the mutational meltdown in a finite diploid population that is evolving continuously in time and subject to resource competition. We model slightly deleterious mutations affecting the population demographic parameters and study how the rate of mutation fixation increases as the genetic load increases, a process that we investigate at two timescales: an ecological scale and a mutational scale. Unlike most previous studies, we treat population size as a random process in continuous time. We show that as deleterious mutations accumulate, the decrease in mean population size accelerates with time relative to a null model with a constant mean fixation time. We quantify this mutational meltdown via the change in the mean fixation time after each new mutation fixation, and we show that the meltdown appears less severe than predicted by earlier theoretical work. We also emphasize that mean population size alone can be a misleading index of the risk of population extinction, which could be better evaluated with additional information on demographic parameters.

Slow-fast stochastic diffusion dynamics and quasi-stationarity for diploid populations with varying size.

We are interested in the long-time behavior of a diploid population with sexual reproduction and randomly varying population size, characterized by its genotype composition at one bi-allelic locus. The population is modeled by a 3-dimensional birth-and-death process with competition, weak cooperation and Mendelian reproduction. This stochastic process is indexed by a scaling parameter

Impact of demography on extinction/fixation events

K

Bayesian estimation of species relative abundances and habitat preferences using opportunistic data

K that goes to infinity, following a large population assumption. When the individual birth and natural death rates are of order

Effects of demographic stochasticity and life-history strategies on times and probabilities to fixation: an individual-based model

K

Slow-fast stochastic diffusion dynamics and quasi-stationary distributions for diploid populations

K, the sequence of stochastic processes indexed by