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Aggressiveness is associated with genetic diversity in landlocked salmon (Salmo salar)

Authors

  • Katriina Tiira,

    1. Integrative Ecology Unit, Department of Ecology and Systematics, Division of Population Biology, PO Box 65, FIN-00014, University of Helsinki, Finland,
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  • Anssi Laurila,

    1. Integrative Ecology Unit, Department of Ecology and Systematics, Division of Population Biology, PO Box 65, FIN-00014, University of Helsinki, Finland,
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    • Present address: Department of Population Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18d, SE-75236 Uppsala, Sweden.

  • Nina Peuhkuri,

    1. Integrative Ecology Unit, Department of Ecology and Systematics, Division of Population Biology, PO Box 65, FIN-00014, University of Helsinki, Finland,
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    • §

      Present address: Finnish Game and Fisheries Research Institute, Kotka Unit, Saponkatu 2, FIN-48100 Kotka, Finland.

  • Jorma Piironen,

    1. Joensuu Game and Fisheries Research, Kauppakatu 18–20, FIN-80100 Joensuu, Finland
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  • Esa Ranta,

    1. Integrative Ecology Unit, Department of Ecology and Systematics, Division of Population Biology, PO Box 65, FIN-00014, University of Helsinki, Finland,
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  • Craig R. Primmer

    Corresponding author
    1. Integrative Ecology Unit, Department of Ecology and Systematics, Division of Population Biology, PO Box 65, FIN-00014, University of Helsinki, Finland,
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Craig Primmer. Fax: + 358 9191 57694; E-mail: craig.primmer@helsinki.fi

Abstract

The amount of intraindividual genetic variation has often been found to have profound effects on life history traits. However, studies concerning the relationship between behaviour and genetic diversity are scarce. Aggressiveness is an important component of competitive ability in juvenile salmonids affecting their later performance and survival. In this study, we used an experimental approach to test the prediction that juveniles with low estimated genetic diversity should be less aggressive than juveniles with high estimated genetic diversity in fry from a highly endangered population of land-locked salmon (Salmo salar). This was achieved by using a method enabling the accurate estimation of offspring genetic diversity based on parental microsatellite genotype data. This allowed us to create two groups of offspring expected to have high or low genetic diversity in which aggressive behaviour could be compared. Salmon fry with low estimated genetic diversity were significantly less aggressive than fry with high estimated genetic diversity. Closer analysis of the data suggested that this difference was due to differences in more costly acts of aggression. Our result may reflect a direct effect of genetic variation on a fitness-related trait; however, we cannot rule out an alternative explanation of allele-specific phenotype matching, where lowered aggression is expressed towards genetically more similar individuals.

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