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A study on the interaction among natural selection, mutation and recombination, with Caenorhabditis elegans experimental evolution

Final Report Summary - EXPTEVOLCELEGANS (A study on the interaction among natural selection, mutation and recombination, with Caenorhabditis elegans experimental evolution)

How populations respond to changing environments is a challenging problem. This is because adaptation and population dynamics, such as extinction, depend on a complex interaction between the breeding mode of individuals, the nature, form and efficacy of natural selection, and the extent of standing levels of genetic variation.
During this project we developed the nematode Caenorhabditis elegans as a model for experimental evolution from standing genetic variation and also set of unique recombinant inbred lines to perform genome-wide association analysis of quantitative traits. We did several evolution experiments that allowed to better understand how adaptation to variable environments depends on the evolution of variable selfing and outcrossing. We showed that the evolutionary transition from outcrossing to selfing is possible if hermaphrodites provide reproductive assurance but once it is possible to maintain intermediate levels of selfing and outcrossing. One of the consequences of maintaining partial selfing, in constant or gradually changing environments, is that excess genetic diversity may be maintained because of balancing selection. In temporally fluctuating environments adaptation depends on the evolution of maternal effects. We have also shown that gradual rates of environmental change can hinder adaptation because of phenotypic plasticity. We expect that the progress that was accomplished by this project will help explain adaptation and extinction of natural populations, especially when they face variable environments.
Major goals of the project were to establish the PI’s team, encourage the team’s international recognition of excellence, and promote the PI’s professional career. All of them were accomplished. During the project the PI become tenured as an associate professor at the École Normale Supérieure in Paris, and the team is now established with 5 researchers, with secured funds for personnel until the end of 2018. The project also allowed the establishment of research collaborations in Europe and the USA. A total of 19 articles, several data sets and analytical software, have been/are expected to be published as a direct result of the project. The material and methods generated during the project have been archived and are being employed by several research teams throughout the world to better understand diverse topics in evolutionary biology, ecology and functional genetics.