Rapid and coupled phenotypic and genetic divergence in Icelandic Arctic char ( Salvelinus alpinus )

Authors:
  • DGDavíð Gíslason
    Davíð Gíslason
  • MFMoira M. Ferguson
    Moira M. Ferguson
  • SSSkúli Skúlason
    Skúli Skúlason
  • SSSigurður S. Snorrason
    Sigurður S. Snorrason
  • KSKurt M. Samways
    Kurt M. Samways
  • PLPeter R. Leavitt
    Peter R. Leavitt
  • PMPierre Magnan
    Pierre Magnan
  • MRMarco A. Rodríguez
    Marco A. Rodríguez
  • PPPedro R. Peres-Neto
    Pedro R. Peres-Neto
  • NGNatalia V. Gordeeva
    Natalia V. Gordeeva
  • SASergey S. Alekseyev
    Sergey S. Alekseyev
  • AMArkadii N. Matveev
    Arkadii N. Matveev
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Abstract
Resource polymorphism has been proposed as an important phase of diversification and speciation in vertebrates. Studies of fish in young lakes of the Northern Hemisphere indicate variably advanced cases of adaptive trophic diversification. We have previously proposed a scheme describing this variation in terms of a gradient of resource-based polymorphic traits, emphasizing flexible behaviour in early phases and morphological divergence in more advanced phases. Here, we present data on Arctic char (Salvelinus alpinus) in Icelandic lakes exhibiting a variable degree of phenotypic and genotypic segregation. We show that (i) the morphs are at different levels of phenotypic segregation and reproductive isolation and in one case completely reproductively isolated, (ii) morphs within lakes appear to be of intralacustrine origin, and (iii) the morphological and genetic divergence of morphs is correlated, suggesting a role for trophic adaptation as a driving force in morph segregation.