Contrasting patterns of selection between MHC I and II across populations of Humboldt and Magellanic penguins |
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Authors: | Nicole Sallaberry‐Pincheira Daniel González‐Acuña Pamela Padilla Gisele P. M. Dantas Guillermo Luna‐Jorquera Esteban Frere Armando Valdés‐Velásquez Juliana A. Vianna |
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Affiliation: | 1. Laboratorio de Biodiversidad Molecular, Departamento de Ecosistemas y Medio Ambiente, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago, Chile;2. Escuela de Medicina Veterinaria, Facultad Ecología y Recursos Naturales, Universidad Andrés Bello, Santiago, Chile;3. Facultad de Ciencias Veterinarias, Universidad de Concepción, Chillán, Chile;4. Pontificia Universidade Catolica de Minas Gerais, Belo Horizonte, Brazil;5. Universidad Católica del Norte, Millenium Nucleus of Ecology and Sustainable Management of Oceanic Islands ESMOI, Centro de Estudios Avanzados en Zonas áridas CEAZA, Coquimbo, Chile;6. Centro de Investigaciones de Puerto Deseado, Universidad Nacional de la Patagonia Austral, Puerto Deseado, Argentina;7. Laboratorio de Estudios en Biodiversidad, Facultad de Ciencias Biológicas y Fisiológicas, Universidad Peruana Cayetano Heredia, Lima, Peru |
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Abstract: | The evolutionary and adaptive potential of populations or species facing an emerging infectious disease depends on their genetic diversity in genes, such as the major histocompatibility complex (MHC). In birds, MHC class I deals predominantly with intracellular infections (e.g., viruses) and MHC class II with extracellular infections (e.g., bacteria). Therefore, patterns of MHC I and II diversity may differ between species and across populations of species depending on the relative effect of local and global environmental selective pressures, genetic drift, and gene flow. We hypothesize that high gene flow among populations of Humboldt and Magellanic penguins limits local adaptation in MHC I and MHC II, and signatures of selection differ between markers, locations, and species. We evaluated the MHC I and II diversity using 454 next‐generation sequencing of 100 Humboldt and 75 Magellanic penguins from seven different breeding colonies. Higher genetic diversity was observed in MHC I than MHC II for both species, explained by more than one MHC I loci identified. Large population sizes, high gene flow, and/or similar selection pressures maintain diversity but limit local adaptation in MHC I. A pattern of isolation by distance was observed for MHC II for Humboldt penguin suggesting local adaptation, mainly on the northernmost studied locality. Furthermore, trans‐species alleles were found due to a recent speciation for the genus or convergent evolution. High MHC I and MHC II gene diversity described is extremely advantageous for the long‐term survival of the species. |
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Keywords: | Adaptation
MHC
positive selection
Spheniscus
trans‐species alleles |
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