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The Role of Eco-Evolutionary Dynamics and Genomic Evolution in Trait Variation

Applicant Mullon Charles
Number 181243
Funding scheme Eccellenza fellowship
Research institution Département d'Ecologie et d'Evolution Faculté de Biologie et de Médecine Université de Lausanne
Institution of higher education University of Lausanne - LA
Main discipline Ecology
Start/End 01.01.2020 - 31.12.2024
Approved amount 1'606'792.00
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Keywords (5)

social evolution; genetic architecture; meta-population; limited dispersal; adaptive dynamics

Lay Summary (French)

Lead
Au sein de toutes les populations, les individus ont des physiologies, des morphologies et des comportements différents. Comment une telle diversité est-elle possible alors que ces individus partagent le même patrimoine génétique et le même environnement ? Ce projet vise à répondre à cette question via la modélisation mathématique.
Lay summary

Un des objectifs fondamentaux de la biologie de l’évolution est de comprendre les processus qui produisent et maintiennent la diversité de la vie entre et au sein des espèces. Les modèles mathématiques nous ont déjà apporté une base théorique pour prendre en compte des facteurs tels que la sélection naturelle et les caractéristiques de l’environnement. Un des défis de cette approche mathématique, souvent trop réductrice, est de mieux représenter la complexité des populations naturelles, de leur écologie et de leur génétique.   

Dans ce contexte, l’objectif de ce projet est d’élaborer de nouveaux modèles mathématiques pour analyser les dynamiques réciproques de la diversité génétique au sein des populations, de la démographie de ces populations et de leur environnement écologique. Nous étudierons d’abord comment la coévolution de plusieurs espèces affecte la diversité au sein des espèces. Puis, nous nous intéresserons à l’évolution des interactions entre gènes à l’intérieur du génome et de son effet sur la diversité phénotypique. Nos recherches aideront à mieux comprendre comment les relations réciproques entre les gènes, les phénotypes, et l’écologie affectent la diversité biologique.

Le projet relève de la recherche fondamentale. Il a pour objectif de générer des prédictions (a) sur les conditions écologiques favorisant la diversité entre individus, et (b) sur la base génétique de cette diversité. Il a des implications dans des domaines de recherche plus appliqués, tels que la gestion de la biodiversité et la conservation.

Direct link to Lay Summary Last update: 12.11.2019

Responsible applicant and co-applicants

Employees

Abstract

A major goal of biology is to understand the mechanisms that contribute to natural variation in quantitative traits. Among the most striking displays of natural variation is the stable coexistence of individuals with highly-differentiated phenotypes. Models to understand how such polymorphism emerges and persists largely rest on the assumption that populations are well-mixed. This condition, however, is rarely met in nature. Because most organisms are dispersal limited, natural populations are very often genetically structured. Such structure has critical consequences for many fundamental ecological and evolutionary processes, from population genomics to social and ecological interactions. Genetic structure is therefore extremely relevant for the origin and maintenance of polymorphism, but a cohesive understanding of its manifold effects is lacking. The aim of this project is to design and analyse mathematical models to better understand how intertwined ecological and evolutionary processes, from genomic changes to community evolution, influence polymorphism and trait variation. My proposal is composed of three lines of research. First, we will investigate the influence of spatial structure on the emergence of polymorphism in ecologically relevant traits, in particular traits that influence local interactions within and between species. We will extend existing adaptive dynamics models to study disruptive selection in a landscape composed of patches that are inhabited by small communities of several species. Our analyses will seek to identify the ecological conditions that lead to polymorphism when these communities are dispersal-limited and co-evolve with one another. Second, we will study how traits under disruptive selection co-evolve with their genetic architecture in spatially structured populations. We will determine the conditions under which modifiers of genetic architecture invade when dispersal is limited. We will focus on dominance modifiers that are due to changes in gene-regulation, and recombination modifiers that are due to chromosomal re-arrangements. This research will help us better understand the relationships between polymorphism and genome biology. Finally, we will study the evolution of differences in gene expression that underlie polymorphism. Using ants as a model system, we will investigate how morph-biased gene expression evolves under the joint action of natural selection and genetic drift. We will first develop a population genetics model for a colony-structured population. We will use this model to make predictions on the influence of colony life-history traits, such as the number of queens per colony, on patterns of morph-biased gene expression. We will then test our predictions using transcriptomic data from 20 ant species. Our results will help disentangle the roles of selection and genetic drift in gene expression differences that are at the basis of polymorphism. The proposed analyses will enable us to better understand the nature of the interplay between evolutionary and ecological change, and provide a clearer picture of the ultimate and proximate causes of polymorphism. The different projects will generate novel insights into the ecological conditions that favour differences between individuals, and into the genomic features that underlie such differences. The proposed research therefore has the potential for a broad scientific impact, with implications for research in evolution, ecology and conservation biology.
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