Conservation Genetics

, Volume 7, Issue 4, pp 515–530

Genetic variation at MHC, mitochondrial and microsatellite loci in isolated populations of Brown trout (Salmo  trutta)

Authors

    • Departamento de Bioquímica, Genética e Inmunología, Facultad de BiologíaUniversidad de Vigo
    • Area de Genética, Edificio de Ciencias ExperimentalesCampus Universitario
  • David Posada
    • Departamento de Bioquímica, Genética e Inmunología, Facultad de BiologíaUniversidad de Vigo
  • Paloma Morán
    • Departamento de Bioquímica, Genética e Inmunología, Facultad de BiologíaUniversidad de Vigo
Article

DOI: 10.1007/s10592-005-9063-z

Cite this article as:
Campos, J., Posada, D. & Morán, P. Conserv Genet (2006) 7: 515. doi:10.1007/s10592-005-9063-z

Abstract

We have studied levels and distribution of genetic variation in nine isolated populations of Brown trout in NW Spain. In the present study, we have tried to test the importance of preservation of genetic variability for the survival of a set of isolated Brown trout (Salmo trutta) populations from the same river drainage. We screened genetic variation in three different markers, mitochondrial, microsatellites and Major Histocompatibility Complex (MHC), presumed to be under different selective pressures. Overall, genetic diversity varied considerably across populations and the distribution of genetic variation was similar at MHC and microsatellites; highly polymorphic populations at the microsatellite loci were also highly polymorphic at the MHC. We also observed high levels of differentiation among populations. Although we found evidence suggesting that balancing selection has influenced the long term evolution of the MHC, genetic drift seems to have eroded the effect of selection, becoming the predominant evolutionary force shaping genetic variation in some of the smaller populations. Despite current lack of variation at the MHC, these small populations seem to have remained viable for a long time.

Keywords

MHC Brown trout Salmo trutta balancing selection ND1 microsatellite

Copyright information

© Springer Science+Business Media, Inc. 2006