"The evolution of genetic architecture"Lesaffre, ThomasOrganisers: Dr. Thomas Lesaffre (thomas.lesaffre@unil.ch; Dept. of Ecology & Evolution, Univ. Lausanne, Switzerland) Prof. Charles Mullon (charles.mullon@unil.ch; Dept. of Ecology & Evolution, Univ. Lausanne, Switzerland) Abstract: A wide range of biological and ecological scenarios can favour the evolution of multiple discrete morphs in one or multiple populations connected by gene flow. These scenarios include intraspecific competition, which can drive character displacement; local adaptation, where different ecotypes are favoured in different locations; and sexual antagonism, which can be resolved by the emergence of sexual dimorphism. Generating phenotypic polymorphism, however, is not straightforward in sexual species, especially when the traits under selection have a polygenic basis. This is because sexual reproduction and recombination constantly break any potential linkage among co-adapted alleles. Such constant genetic reshuffling hinders the emergence of polymorphism and leads to the production of less fit intermediate phenotypes. To avoid the fitness loss associated with producing these intermediates, selection can act on the genetic architecture of traits to ensure greater trait heritability and the maintenance of the extreme types favoured by selection. This may happen through the evolution of modifiers affecting allele segregation and effect sizes, recombination, gene expression, or dominance. Recent advances in molecular approaches have revealed a wide variety of ways these modifiers come about, ranging from supergenes established via chromosomal inversions, to chromosomal fusions or the evolution of regulatory elements, such as small RNAs inhibiting or promoting the expression of specific genes. We propose a symposium to bring together scientists who use mathematical and computational modelling to understand how genetic architecture evolves, and how it can contribute to the coexistence of different phenotypes in complex environments. We have lined up four potential speakers whose work explores different aspects of genetic architecture evolution, including the evolution of dominance modifiers and regulatory sequences in response to sexual antagonism, the emergence and long-term maintenance of supergenes involved in local adaptation, and the build-up of genetic covariances between quantitative traits in response to selection for a changing optimum. Their research contributes to our understanding of the emergence and maintenance of trait variation within species, with implications for adaptation, speciation, and biodiversity. |
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