JCJC - Jeunes chercheuses & jeunes chercheurs

Epidémiologie évolutive et coévolutive – EPICE

Submission summary

The emergence and re-emergence of infectious diseases is an ever increasing source of concern. Understanding the dynamics of parasite populations may help limit the potentially devastating consequences of epidemics for animal and plant species. Yet a full comprehension of this dynamics requires multiple perspectives: (i) epidemiology, (ii) parasite evolution and (iii) host-parasite coevolution. So far these three different bodies of research have been developed independently and our goal is to reconcile these different approaches. In the theoretical part of the project our ambition is to lay the foundations for a new theoretical framework that will merge epidemiological, evolutionary and coevolutionary dynamics. This will allow us to explore three main components of host and parasite evolution: (1) The evolution of phenotypic traits. We will explore the coevolutionary dynamics between virulence and immune evasion in influenza. We will also analyse the evolution of drug resistance in an epidemiological model where the use of treatments may vary in space. (2) The evolution of mean fitness. In particular, we will focus on the dynamics of mean fitness across space and time. We will study the effects of migration, genetic drift and mosaics of selection on the emergence of local adaptation. (3) The evolution of traits (mutation, recombination, migration) affecting the evolutionary potential and, consequently, the level of adaptation. The second aim of this project is to develop an experimental bacteria-phage system (Escherichia coli and the lytic phage phix174) that will enable us to test the above theoretical predictions on the evolution of phenotypic traits and on the emergence of local adaptation. For this purpose we will carry out a series of evolution and coevolution experiments to study three main aspects of this bacteria-phage interaction: (1) The evolution of phage life history traits. We will study the effect of both bacteria and phage densities on the evolution of phage lysis time. (2) The emergence of parasite local adaptation. We will study the interaction between the effects of host and parasite migration rates, genetic drift and mosaics of selection on the sign and the magnitude of phage local adaptation. (3) The specificity of the interaction between a bacteria and its phage. We will characterise the pattern of specificity (polymorphism, costs associated with bacteria resistance and phage infectivity) emerging in our bacteria-phage coevolving populations. The originality of this project lays in our ambition to reconcile epidemiology, evolution and coevolution within a single theoretical framework. Our project will address similar questions on the evolution of host-parasite interactions with both a theoretical and an experimental approach because we believe in the importance of feedbacks between these two lines of research. The experimental system will help focus the theory on relevant and testable issues. In return, the theoretical framework will help design experiments and make predictions to better understand the evolutionary and coevolutionary dynamics of our biological system.

Project coordination

Sylvain GANDON (Organisme de recherche)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

Help of the ANR 199,368 euros
Beginning and duration of the scientific project: - 48 Months

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