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Evidence for genetic distinction among sympatric ecotypes of Arctic char ( S alvelinus alpinus ) in south‐western A laskan lakes
Author(s) -
MayMcNally Shannan L.,
Quinn Thomas P.,
Woods Pamela J.,
Taylor Eric B.
Publication year - 2015
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1111/eff.12169
Subject(s) - salvelinus , arctic char , sympatric speciation , biology , ecology , ecotype , genetic divergence , arctic , sympatry , genetic diversity , range (aeronautics) , zoology , trout , fishery , population , materials science , demography , sociology , fish <actinopterygii> , composite material
Resource polymorphism may play an important role in the process of speciation. The Arctic char ( S alvelinus alpinus ) exhibits great phenotypic and genetic diversity across its range, making it an ideal species for studies of resource polymorphism and divergence. Here, we investigated genetic variation at 11 microsatellite loci among 287 Arctic char from five isolated yet proximate postglacial lakes in south‐western Alaska that were previously examined for resource polymorphism. Significant differences in pairwise F ST were detected among all lakes (range from 0.05 to 0.28, all P < 0.02). In one lake (Lower Tazimina Lake), we found evidence for two genetic groups of char and for significant differences in the distribution of microsatellite variability among at least two of the three previously described body size morphotypes (‘large’‐, ‘medium’‐, and ‘small’‐bodied char; maximum F ST = 0.09; differences in admixture proportions). We also found a significant association between genetic admixture proportions and gill raker counts among body size morphs ( r = −0.73, P < 0.001). Our data represent the first record of genetically distinct sympatric morphs of Arctic char in Alaska and provide further evidence that differences in morphology associated with feeding (gill rakers) and growth trajectories reflect niche diversification and promote genetic divergence in Holarctic populations of Arctic char.