Using Reciprocal Transplants to Assess Local Adaptation, Genetic Rescue, and Sexual Selection in Newly Established Populations

• Published in: Genes
• Main Authors: Labonne, Jacques, Manicki, Aurélie, Chevalier, Louise, Tétillon, Marin, Guéraud, François, Hendry, Andrew
• Other Authors: Ecologie Comportementale et Biologie des Populations de Poissons (ECOBIOP), Université de Pau et des Pays de l'Adour (UPPA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Redpath Museum and Department of Biology, McGill University = Université McGill Montréal, Canada, SALMEVOL-1041/Institut Polaire Français Paul Emile Victor, INRAE - National Research Institute for Agriculture, Food and the Environment (France)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: genetic rescue; local adaptation; mating success; gene flow; small population; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.GEN.GPO]Life Sciences [q-bio]/Genetics/Populations and Evolution [q-bio.PE]; Antarctic; Kerguelen; Kerguelen Islands; Antarc*
• Online Access: https://hal.inrae.fr/hal-03102333; https://hal.inrae.fr/hal-03102333/document; https://hal.inrae.fr/hal-03102333/file/2021_Labonne_Genes.pdf; https://doi.org/10.3390/genes12010005

International audience Small populations establishing on colonization fronts have to adapt to novel environments with limited genetic variation. The pace at which they can adapt, and the influence of genetic variation on their success, are key questions for understanding intraspecific diversity. To investigate these topics, we performed a reciprocal transplant experiment between two recently founded populations of brown trout in the sub-Antarctic Kerguelen Islands. Using individual tagging and genetic assignment methods, we tracked the fitness of local and foreign individuals, as well as the fitness of their offspring over two generations. In both populations, although not to the same extent, gene flow occurred between local and foreign gene pools. In both cases, however, we failed to detect obvious footprints of local adaptation (which should limit gene flow) and only weak support for genetic rescue (which should enhance gene flow). In the population where gene flow from foreign individuals was low, no clear differences were observed between the fitness of local, foreign, and F1 hybrid individuals. In the population where gene flow was high, foreign individuals were successful due to high mating success rather than high survival, and F1 hybrids had the same fitness as pure local offspring. These results suggest the importance of considering sexual selection, rather than just local adaptation and genetic rescue, when evaluating the determinants of success in small and recently founded populations.