Evidence of Pathogen-Induced Immunogenetic Selection across the Large Geographic Range of a Wild Seabird

• Published in: Molecular Biology and Evolution
• Main Authors: Levy, Hila, Fiddaman, Steven, Vianna, Juliana, Noll, Daly, Clucas, Gemma, Sidhu, Jasmine, Polito, Michael, Bost, Charles, Phillips, Richard, Crofts, Sarah, Miller, Gary, Pistorius, Pierre, Bonadonna, Francesco, Le Bohec, Céline, Barbosa, Andrés, Trathan, Phil, Raya Rey, Andrea, Frantz, Laurent, Hart, Tom, Smith, Adrian
• Other Authors: Department of Zoology Oxford, University of Oxford Oxford, Department of Zoology, Peter Medawar Building for Pathogen Research UK, Departamento de Ecosistemas y Medio Ambiente Chile, Pontificia Universidad Católica de Chile (UC), Atkinson Center for a Sustainable Future and Cornell Lab of Ornithology USA, Cornell University New York, Department of Oceanography and Coastal Sciences, Louisiana State University (LSU), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Falklands Conservation, Carnegie Mellon University Pittsburgh (CMU), National Research Foundation Centre of Excellence at the Percy FitzPatrick Institute, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD France-Sud ), Département Ecologie, Physiologie et Ethologie (DEPE-IPHC), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Departamento de Ecología Evolutiva (Museo Nacional de Ciencias Naturales), Museo Nacional de Ciencias Naturales (MNCN), Centro Austral de Investigaciones Científicas Ushuaia (CADIC), Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires (CONICET), School of Biological and Chemical Sciences, Queen Mary University of London (QMUL)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Gentoo penguin; Antarctica and Southern Ocean; immunogenetics; positive selection; Toll-like receptors; pathogen-mediated selection; [SDV.BA]Life Sciences [q-bio]/Animal biology; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.NEU.PC]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Psychology and behavior; Southern Ocean; Antarc*; Antarctica; Pygoscelis papua
• Online Access: https://hal.archives-ouvertes.fr/hal-02988644; https://hal.archives-ouvertes.fr/hal-02988644/document; https://hal.archives-ouvertes.fr/hal-02988644/file/Levy%202020%20HAL.pdf; https://doi.org/10.1093/molbev/msaa040

International audience Over evolutionary time, pathogen challenge shapes the immune phenotype of the host to better respond to an incipient threat. The extent and direction of this selection pressure depends on the local pathogen composition, which is in turn determined by biotic and abiotic features of the environment. However, little is known about adaptation to local pathogen threats in wild animals. The Gentoo penguin (Pygoscelis papua) is a species complex that lends itself to the study of immune adaptation because of its circumpolar distribution over a large latitudinal range, with little or no admixture between different clades. In this study, we examine the diversity in a key family of innate immune genes - the Toll-like receptors (TLRs) - across the range of the Gentoo. The three TLRs that we investigated present varying levels of diversity, with TLR4 and TLR5 greatly exceeding the diversity of TLR7. We present evidence of positive selection in TLR4 and TLR5, which points to pathogen-driven adaptation to the local pathogen milieu. Finally, we demonstrate that two positively selected co-segregating sites in TLR5 are sufficient to alter the responsiveness of the receptor to its bacterial ligand, flagellin. Taken together, these results suggest that Gentoo penguins have experienced distinct pathogen-driven selection pressures in different environments, which may be important given the role of the Gentoo as a sentinel species in some of the world's most rapidly changing environments.