Fin whale MDH-1 and MPI allozyme variation is not reflected in the corresponding DNA sequences

Authors

  • Morten Tange Olsen,

    Corresponding author
    1. Evolutionary Genetics Group, Department of Genetics, Microbiology, and Toxicology, Stockholm University, S-106 91 Stockholm, Sweden
    • Correspondence

      Morten Tange, Section for Evolutionary Genomics, Centre for Geogenetics, Natural History Museum of Denmark, University of Copenhagen,Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark. Tel: +45 42661525; Fax: +45 35322325; E-mail: mortentolsen@gmail.com

      Per J. Palsbøll, Marine Evolution and Conservation, Centre for Ecological and Evolutionary Studies, University of Groningen, PO Box 11103, 9700 CC Groningen, The Netherlands. Tel: +31 50 363 9882;

      Fax: +31 (0)50 363 9620;

      E-mail: p.j.palsboll@rug.nl

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  • Christophe Pampoulie,

    1. Marine Research Institute, IS-101 Reykjavík, Iceland
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  • Anna K. Daníelsdóttir,

    1. Matís, IS-113 Reykjavík, Iceland
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  • Emmelie Lidh,

    1. Evolutionary Genetics Group, Department of Genetics, Microbiology, and Toxicology, Stockholm University, S-106 91 Stockholm, Sweden
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  • Martine Bérubé,

    1. Evolutionary Genetics Group, Department of Genetics, Microbiology, and Toxicology, Stockholm University, S-106 91 Stockholm, Sweden
    2. Marine Evolution and Conservation, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands
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  • Gísli A. Víkingsson,

    1. Marine Research Institute, IS-101 Reykjavík, Iceland
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  • Per J. Palsbøll

    Corresponding author
    1. Evolutionary Genetics Group, Department of Genetics, Microbiology, and Toxicology, Stockholm University, S-106 91 Stockholm, Sweden
    2. Marine Evolution and Conservation, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands
    • Correspondence

      Morten Tange, Section for Evolutionary Genomics, Centre for Geogenetics, Natural History Museum of Denmark, University of Copenhagen,Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark. Tel: +45 42661525; Fax: +45 35322325; E-mail: mortentolsen@gmail.com

      Per J. Palsbøll, Marine Evolution and Conservation, Centre for Ecological and Evolutionary Studies, University of Groningen, PO Box 11103, 9700 CC Groningen, The Netherlands. Tel: +31 50 363 9882;

      Fax: +31 (0)50 363 9620;

      E-mail: p.j.palsboll@rug.nl

    Search for more papers by this author

Abstract

The appeal of genetic inference methods to assess population genetic structure and guide management efforts is grounded in the correlation between the genetic similarity and gene flow among populations. Effects of such gene flow are typically genomewide; however, some loci may appear as outliers, displaying above or below average genetic divergence relative to the genomewide level. Above average population, genetic divergence may be due to divergent selection as a result of local adaptation. Consequently, substantial efforts have been directed toward such outlying loci in order to identify traits subject to local adaptation. Here, we report the results of an investigation into the molecular basis of the substantial degree of genetic divergence previously reported at allozyme loci among North Atlantic fin whale (Balaenoptera physalus) populations. We sequenced the exons encoding for the two most divergent allozyme loci (MDH-1 and MPI) and failed to detect any nonsynonymous substitutions. Following extensive error checking and analysis of additional bioinformatic and morphological data, we hypothesize that the observed allozyme polymorphisms may reflect phenotypic plasticity at the cellular level, perhaps as a response to nutritional stress. While such plasticity is intriguing in itself, and of fundamental evolutionary interest, our key finding is that the observed allozyme variation does not appear to be a result of genetic drift, migration, or selection on the MDH-1 and MPI exons themselves, stressing the importance of interpreting allozyme data with caution. As for North Atlantic fin whale population structure, our findings support the low levels of differentiation found in previous analyses of DNA nucleotide loci.

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