Smadi, Charline
Overview
Works:  6 works in 6 publications in 2 languages and 7 library holdings 

Roles:  Author, Other, Opponent, Thesis advisor 
Publication Timeline
.
Most widely held works by
Charline Smadi
The Effect of Recurrent Mutations on Genetic Diversity in a Large Population of Varying Size by
Charline Smadi(
)
1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide
A stochastic model for speciation by mating preferences by
Camille Coron(
)
1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide
Looking for the right mate in diploid species: How does genetic dominance affect the spatial differentiation of a sexual trait?(
)
1 edition published in 2018 in English and held by 1 WorldCat member library worldwide
Highlights: Assortative mating promoting migration drives spatial variation in preferred traits. In diploid model, codominant preference alleles can limit spatial differentiation. Dominance maintains spatial segregation despite stronger migration as codominance. Dominance between alleles can also favor local polymorphism. Our results stress out the need of diploid models of trait divergence and speciation. Abstract: Divergence between populations for a given trait can be driven by sexual selection, interacting with migration behaviour. Mating preference for different phenotypes may lead to specific migration behaviour, with departures from populations where the preferred trait is rare. Such preferences can then trigger the emergence and persistence of differentiated populations, even without any local adaptation. However the genetic architecture underlying the trait targeted by mating preference may have a profound impact on population divergence. In particular, dominance between alleles encoding for divergent phenotypes can interfere with the differentiation process. Using a diploid model of a trait determining both mating success and migration rate, we explored differentiation between two connected populations, assuming either codominance or strict dominance between alleles. The model assumes that individuals prefer mating with partners displaying the same phenotype and therefore tend to move to the other population when their own phenotype is rare. We show that the emergence of differentiated populations in this diploid moded is limited as compared to results obtained with the same model assuming haploidy. When assuming codominance, differentiation arises only when migration is limited compared to the strength of the preference. Such differentiation is less dependent on migration when assuming strict dominance between haplotypes. Dominant alleles frequently invade populations because their phenotype is more frequently expressed, resulting in higher local mating success and a rapid decrease in migration. However, depending on the initial distribution of alleles, this advantage associated with dominance (i.e. Haldane's sieve) may lead to fixation of the dominant allele throughout both populations. Depending on the initial distribution of heterozygotes in the two populations, persistence of polymorphisms within populations can also occur because heterozygotes displaying the predominant phenotype benefit from high mating success. Altogether, our results highlight that heterozygotes' behaviour has a strong impact on population differentiation and highlight the need for diploid models of differentiation and speciation driven by sexual selection
1 edition published in 2018 in English and held by 1 WorldCat member library worldwide
Highlights: Assortative mating promoting migration drives spatial variation in preferred traits. In diploid model, codominant preference alleles can limit spatial differentiation. Dominance maintains spatial segregation despite stronger migration as codominance. Dominance between alleles can also favor local polymorphism. Our results stress out the need of diploid models of trait divergence and speciation. Abstract: Divergence between populations for a given trait can be driven by sexual selection, interacting with migration behaviour. Mating preference for different phenotypes may lead to specific migration behaviour, with departures from populations where the preferred trait is rare. Such preferences can then trigger the emergence and persistence of differentiated populations, even without any local adaptation. However the genetic architecture underlying the trait targeted by mating preference may have a profound impact on population divergence. In particular, dominance between alleles encoding for divergent phenotypes can interfere with the differentiation process. Using a diploid model of a trait determining both mating success and migration rate, we explored differentiation between two connected populations, assuming either codominance or strict dominance between alleles. The model assumes that individuals prefer mating with partners displaying the same phenotype and therefore tend to move to the other population when their own phenotype is rare. We show that the emergence of differentiated populations in this diploid moded is limited as compared to results obtained with the same model assuming haploidy. When assuming codominance, differentiation arises only when migration is limited compared to the strength of the preference. Such differentiation is less dependent on migration when assuming strict dominance between haplotypes. Dominant alleles frequently invade populations because their phenotype is more frequently expressed, resulting in higher local mating success and a rapid decrease in migration. However, depending on the initial distribution of alleles, this advantage associated with dominance (i.e. Haldane's sieve) may lead to fixation of the dominant allele throughout both populations. Depending on the initial distribution of heterozygotes in the two populations, persistence of polymorphisms within populations can also occur because heterozygotes displaying the predominant phenotype benefit from high mating success. Altogether, our results highlight that heterozygotes' behaviour has a strong impact on population differentiation and highlight the need for diploid models of differentiation and speciation driven by sexual selection
Dynamique du modèle de Moran en environnement aléatoire by
Arnaud Personne(
)
1 edition published in 2019 in French and held by 1 WorldCat member library worldwide
In some ecosystems and more particularly in virgin tropical forests, different species having the same ecological requirements coexist in the same environment. For example, some forests have over a hundred different tree species on one hectare. To explain this incrediblediversity, scientists have built models in which the community composition isonly due to the stochastic dispersion of individuals.The mathematical model studied in this thesis follows this line. It was suggested by Mr. Kalyuzhni in an article where he justifies its relevance. It is known as the Moran model in random environment. It is therefore a question of studying a birth and death process taking into account the environmental stochasticity (climates, diseases, etc.) To study this dynamic, we use an approximation by a diffusion, on the classical scale where the acceleration in time is given by the square of the population size, moreover selective advantage and immigration are inversely proportional to thethis size. The selective advantage varies randomly and is modeled by a Markov jump process. We study the convergence in law of the processes sequence and give a quantitative estimate of the error made for a given population. We are then interested in the moments estimation of the population frequencies, motivated in particular by biodiversity indices such as the Simpson's index andbased on the approximations obtained before.In the case of a nonzero selection, the stochastic differential equation governing a moment appeals to the higher order moment. To overcome this difficulty, we create a closure method to reduce the study of the first moments to a finite system of differential equations. We give an estimation of the error made by neglecting the terms of higher degrees. Finally, in the case of two species and with constant coefficients, we give an estimate of the convergence speed of the diffusion towards the stationary measure. In a second time, we are interested in a time scale proportional to the size of the population. This leads to a convergence of the process law towards a deterministic limitcharacterized by an ordinary differential equation. The selection coefficient evolving randomly, still following a Markov jump process, this process is a PDMP.We then study the persistence of the different species and the potential coexistencethanks the persistence theory, developed by Benaïm and Schreiber. In this part, we are particularly interested in the case where all the species persist. With only two environments: we show that two species can persist but not three. With more environments,the explicit classification stay an open problem but an example of persistence with three speciesand three environments is given
1 edition published in 2019 in French and held by 1 WorldCat member library worldwide
In some ecosystems and more particularly in virgin tropical forests, different species having the same ecological requirements coexist in the same environment. For example, some forests have over a hundred different tree species on one hectare. To explain this incrediblediversity, scientists have built models in which the community composition isonly due to the stochastic dispersion of individuals.The mathematical model studied in this thesis follows this line. It was suggested by Mr. Kalyuzhni in an article where he justifies its relevance. It is known as the Moran model in random environment. It is therefore a question of studying a birth and death process taking into account the environmental stochasticity (climates, diseases, etc.) To study this dynamic, we use an approximation by a diffusion, on the classical scale where the acceleration in time is given by the square of the population size, moreover selective advantage and immigration are inversely proportional to thethis size. The selective advantage varies randomly and is modeled by a Markov jump process. We study the convergence in law of the processes sequence and give a quantitative estimate of the error made for a given population. We are then interested in the moments estimation of the population frequencies, motivated in particular by biodiversity indices such as the Simpson's index andbased on the approximations obtained before.In the case of a nonzero selection, the stochastic differential equation governing a moment appeals to the higher order moment. To overcome this difficulty, we create a closure method to reduce the study of the first moments to a finite system of differential equations. We give an estimation of the error made by neglecting the terms of higher degrees. Finally, in the case of two species and with constant coefficients, we give an estimate of the convergence speed of the diffusion towards the stationary measure. In a second time, we are interested in a time scale proportional to the size of the population. This leads to a convergence of the process law towards a deterministic limitcharacterized by an ordinary differential equation. The selection coefficient evolving randomly, still following a Markov jump process, this process is a PDMP.We then study the persistence of the different species and the potential coexistencethanks the persistence theory, developed by Benaïm and Schreiber. In this part, we are particularly interested in the case where all the species persist. With only two environments: we show that two species can persist but not three. With more environments,the explicit classification stay an open problem but an example of persistence with three speciesand three environments is given
Émergence et contrôle des épidémies dans les populations humaines by
Marina Voinson(
)
1 edition published in 2018 in French and held by 1 WorldCat member library worldwide
Infectious diseases have shaped the history of the human species. Nowadays, the emergence of new pathogens threatens public health. Understanding the interaction between pathogen ecology and human behaviour can help understanding the dynamics observed in human populations. In this thesis, two main axes were studied: the epidemic dynamics of emerging infectious diseases (EID's) in human populations and the impact of human behaviour on the control of infectious diseases. The epidemic dynamics of emerging pathogens is poorly understood because it is often studied without taking into account the effect of their characteristics, namely their persistence in a reservoir population and their ability to emerge in a broad range of species. For the first time, we modeled the dynamics of EID's and highlighted that transmission from both the reservoir and intermediate populations are critically important to consider in order to understand the many and unpredictable outbreaks that can be observed. Thereafter, the impact of human behaviour on infectious diseases control was studied by considering two aspects, vaccination decisionmaking and cultural practices. We show that consideration of cognitive biases related to vaccination decisionmaking and the interaction between behaviour and epidemiology can lead to the fluctuations observed in vaccination coverage. Finally, the study of cultural practices has shown that, although often assumed to favour the spread of pathogens in a population, certain practices can limit disease transmission. The results taken together suggest that an ecological approach is key for predicting the dynamics underpinning the emergence and reemergence of infectious diseases and adapt control strategies
1 edition published in 2018 in French and held by 1 WorldCat member library worldwide
Infectious diseases have shaped the history of the human species. Nowadays, the emergence of new pathogens threatens public health. Understanding the interaction between pathogen ecology and human behaviour can help understanding the dynamics observed in human populations. In this thesis, two main axes were studied: the epidemic dynamics of emerging infectious diseases (EID's) in human populations and the impact of human behaviour on the control of infectious diseases. The epidemic dynamics of emerging pathogens is poorly understood because it is often studied without taking into account the effect of their characteristics, namely their persistence in a reservoir population and their ability to emerge in a broad range of species. For the first time, we modeled the dynamics of EID's and highlighted that transmission from both the reservoir and intermediate populations are critically important to consider in order to understand the many and unpredictable outbreaks that can be observed. Thereafter, the impact of human behaviour on infectious diseases control was studied by considering two aspects, vaccination decisionmaking and cultural practices. We show that consideration of cognitive biases related to vaccination decisionmaking and the interaction between behaviour and epidemiology can lead to the fluctuations observed in vaccination coverage. Finally, the study of cultural practices has shown that, although often assumed to favour the spread of pathogens in a population, certain practices can limit disease transmission. The results taken together suggest that an ecological approach is key for predicting the dynamics underpinning the emergence and reemergence of infectious diseases and adapt control strategies
Stochastic dynamics of three competing clones : conditions and times for invasion, coexistence, and fixation by
Sylvain Billiard(
)
1 edition published in 2020 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 2020 in English and held by 0 WorldCat member libraries worldwide
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