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Kjartan Ostbye - One of the best experts on this subject based on the ideXlab platform.
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Diversifying selection drives parallel evolution of Gill Raker number and body size along the speciation continuum of European whitefish
Ecology and Evolution, 2018Co-Authors: Katja Häkli, Per-arne Amundsen, Kimmo K. Kahilainen, Kjartan Ostbye, Kim PræbelAbstract:Adaptive radiation is the evolution of ecological and phenotypical diversity. It arises via ecological opportunity that promotes the exploration of underutilized or novel niches mediating specialization and reproductive isolation. The assumed precondition for rapid local adaptation is diversifying natural selection, but random genetic drift could also be a major driver of this process. We used 27 populations of European whitefish (Coregonus lavaretus) from nine lakes distributed in three neighboring subarctic watercourses in northern Fennoscandia as a model to test the importance of random drift versus diversifying natural selection for parallel evolution of adaptive phenotypic traits. We contrasted variation for two key adaptive phenotypic traits correlated with resource utilization of polymorphic fish; the number of Gill Rakers and the total length of fish, with the posterior distribution of neutral genetic differentiation from 13 microsatellite loci, to test whether the observed phenotypic divergence could be achieved by random genetic drift alone. Our results show that both traits have been under diversifying selection and that the evolution of these morphs has been driven by isolation through habitat adaptations. We conclude that diversifying selection acting on Gill Raker number and body size has played a significant role in the ongoing adaptive radiation of European whitefish morphs in this region.
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ongoing niche differentiation under high gene flow in a polymorphic brackish water threespine stickleback gasterosteus aculeatus population
BMC Evolutionary Biology, 2018Co-Authors: Kjartan Ostbye, Louis Bernatchez, Annette Taugbol, Mark Ravinet, Chris Harrod, Ruben Alexander Pettersen, Leif Asbjørn VøllestadAbstract:Background Marine threespine sticklebacks colonized and adapted to brackish and freshwater environments since the last Pleistocene glacial. Throughout the Holarctic, three lateral plate morphs are observed; the low, partial and completely plated morph. We test if the three plate morphs in the brackish water Lake Engervann, Norway, differ in body size, trophic morphology (Gill Raker number and length), niche (stable isotopes; δ15N, δ13C, and parasites (Theristina gasterostei, Trematoda spp.)), genetic structure (microsatellites) and the lateral-plate encoding Stn382 (Ectodysplasin) gene. We examine differences temporally (autumn 2006/spring 2007) and spatially (upper/lower sections of the lake – reflecting low versus high salinity).
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evolutionary history of the european whitefish coregonus lavaretus l species complex as inferred from mtdna phylogeography and Gill Raker numbers
Molecular Ecology, 2005Co-Authors: Kjartan Ostbye, Louis Bernatchez, T F Naesje, K J M Himberg, Kjetil HindarAbstract:We compared mitochondrial DNA and Gill-Raker number variation in populations of the European whitefish Coregonus lavaretus (L.) species complex to illuminate their evolutionary history, and discuss mechanisms behind diversification. Using single-strand conformation polymorphism (SSCP) and sequencing 528 bp of combined parts of the cytochrome oxidase b (cyt b ) and NADH dehydrogenase subunit 3 (ND3) mithochondrial DNA (mtDNA) regions, we documented phylogeographic relationships among populations and phylogeny of mtDNA haplotypes. Demographic events behind geographical distribution of haplotypes were inferred using nested clade analysis (NCA) and mismatch distribution. Concordance between operational taxonomical groups, based on Gill-Raker numbers, and mtDNA patterns was tested. Three major mtDNA clades were resolved in Europe: a North European clade from northwest Russia to Denmark, a Siberian clade from the Arctic Sea to southwest Norway, and a South European clade from Denmark to the European Alps, reflecting occupation in different glacial refugia. Demographic events inferred from NCA were isolation by distance, range expansion, and fragmentation. Mismatch analysis suggested that clades which colonized Fennoscandia and the Alps expanded in population size 24 500–5800 years before present, with minute female effective population sizes, implying small founder populations during colonization. Gill-Raker counts did not commensurate with hierarchical mtDNA clades, and poorly with haplotypes, suggesting recent origin of Gill-Raker variation. Whitefish designations based on Gill-Raker numbers were not associated with ancient clades. Lack of congruence in morphology and evolutionary lineages implies that the taxonomy of this species complex should be reconsidered.
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Evolutionary history of the European whitefish Coregonus lavaretus (L.) species complex as inferred from mtDNA phylogeography and Gill‐Raker numbers
Molecular Ecology, 2005Co-Authors: Kjartan Ostbye, Louis Bernatchez, T F Naesje, K J M Himberg, Kjetil HindarAbstract:We compared mitochondrial DNA and Gill-Raker number variation in populations of the European whitefish Coregonus lavaretus (L.) species complex to illuminate their evolutionary history, and discuss mechanisms behind diversification. Using single-strand conformation polymorphism (SSCP) and sequencing 528 bp of combined parts of the cytochrome oxidase b (cyt b ) and NADH dehydrogenase subunit 3 (ND3) mithochondrial DNA (mtDNA) regions, we documented phylogeographic relationships among populations and phylogeny of mtDNA haplotypes. Demographic events behind geographical distribution of haplotypes were inferred using nested clade analysis (NCA) and mismatch distribution. Concordance between operational taxonomical groups, based on Gill-Raker numbers, and mtDNA patterns was tested. Three major mtDNA clades were resolved in Europe: a North European clade from northwest Russia to Denmark, a Siberian clade from the Arctic Sea to southwest Norway, and a South European clade from Denmark to the European Alps, reflecting occupation in different glacial refugia. Demographic events inferred from NCA were isolation by distance, range expansion, and fragmentation. Mismatch analysis suggested that clades which colonized Fennoscandia and the Alps expanded in population size 24 500–5800 years before present, with minute female effective population sizes, implying small founder populations during colonization. Gill-Raker counts did not commensurate with hierarchical mtDNA clades, and poorly with haplotypes, suggesting recent origin of Gill-Raker variation. Whitefish designations based on Gill-Raker numbers were not associated with ancient clades. Lack of congruence in morphology and evolutionary lineages implies that the taxonomy of this species complex should be reconsidered.
Rebecca S. Piercey - One of the best experts on this subject based on the ideXlab platform.
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Going, going, gone: evidence for loss of an endemic species pair of threespine sticklebacks (Gasterosteus aculeatus) with implications for protection under species-at-risk legislation
Conservation Genetics, 2018Co-Authors: Eric B. Taylor, Rebecca S. PierceyAbstract:Genomic extinction occurs when the unique combination of genetic traits that characterize distinct phenotypes are eliminated by introgressive hybridization even if population size is greater than zero. Benthic and limnetic threespine sticklebacks ( Gasterosteus aculeatus ) constitute reproductively isolated undescribed biological species that have evolved independently in several lakes in southwestern British Columbia, Canada (known as “species pairs” in each lake). Here we investigated whether the two species that comprise the pair from Enos Lake, southeastern Vancouver Island, remain as two distinct gene pools. Multi-season samples (>1200 fish) obtained over two years from throughout the lake and assayed for variation in morphological traits characteristic of the two species (i.e., body depth, dorsal spine count, Gill Raker counts) and at 12 microsatellite DNA loci consistently indicated the existence of only a single group of sticklebacks. There was no consistent evidence of two groups in any morphological trait, and mean Gill Raker counts were consistently intermediate (20–21) to those of known benthics (~18) and limnetics (~24) which together comprised strikingly bimodal distributions in historical samples. Genetic analyses employing model-based clustering also consistently indicated the presence of only a single genetic group of sticklebacks. Compared to historical samples and to benthics and limnetics from other lakes, no Enos Lake fish could be identified confidently as a pure benthic or limnetic. Our results provide the strongest evidence yet that the Enos Lake sticklebacks now consist of a single morphological and genetic population of sticklebacks, that the unique combination of genetic and morphological traits that characterized benthic and limnetic sticklebacks no longer exist, and that their current status under Canada’s Species-at Risk Act as Endangered should be re-evaluated.
Louis Bernatchez - One of the best experts on this subject based on the ideXlab platform.
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ongoing niche differentiation under high gene flow in a polymorphic brackish water threespine stickleback gasterosteus aculeatus population
BMC Evolutionary Biology, 2018Co-Authors: Kjartan Ostbye, Louis Bernatchez, Annette Taugbol, Mark Ravinet, Chris Harrod, Ruben Alexander Pettersen, Leif Asbjørn VøllestadAbstract:Background Marine threespine sticklebacks colonized and adapted to brackish and freshwater environments since the last Pleistocene glacial. Throughout the Holarctic, three lateral plate morphs are observed; the low, partial and completely plated morph. We test if the three plate morphs in the brackish water Lake Engervann, Norway, differ in body size, trophic morphology (Gill Raker number and length), niche (stable isotopes; δ15N, δ13C, and parasites (Theristina gasterostei, Trematoda spp.)), genetic structure (microsatellites) and the lateral-plate encoding Stn382 (Ectodysplasin) gene. We examine differences temporally (autumn 2006/spring 2007) and spatially (upper/lower sections of the lake – reflecting low versus high salinity).
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Speciation Reversal in European Whitefish (Coregonus lavaretus (L.)) Caused by Competitor Invasion
2016Co-Authors: Shripathi Bhat, Per-arne Amundsen, Rune Knudsen, Louis Bernatchez, Karl Øystein Gjell, Svein-erik Fevolden, Kim PræbelAbstract:Invasion of exotic species has caused the loss of biodiversity and imparts evolutionary and ecological changes in the introduced systems. In northern Fennoscandia, European whitefish (Coregonus lavaretus (L.)) is a highly polymorphic species displaying adaptive radiations into partially reproductively isolated and thus genetically differentiated sympatric morphs utilizing the planktivorous and benthivorous food niche in many lakes. In 1993, Lake Skrukkebukta was invaded by vendace (Coregonus albula (L.)) which is a zooplanktivorous specialist. The vendace displaced the densely Rakered whitefish from its preferred pelagic niche to the benthic habitat harbouring the large sparsely Rakered whitefish. In this study, we investigate the potential influence of the vendace invasion on the breakdown of reproductive isolation between the two whitefish morphs. We inferred the genotypic and phenotypic differentiation between the two morphs collected at the arrival (1993) and 15 years after (2008) the vendace invasion using 16 microsatellite loci and Gill Raker numbers, the most distinctive adaptive phenotypic trait between them. The comparison of Gill Raker number distributions revealed two modes growing closer over 15 years following the invasion. Bayesian analyses of genotypes revealed that the two genetically distinct whitefish morphs that existed in 1993 had collapsed into a single population in 2008. The decline in association between the Gill Raker numbers and admixture values over 15 years corroborates the findings from the Bayesian analysis. Our study thus suggests an apparent decrease of reproductive isolation in a morph-pair of European whitefish within 15 years (.
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evolutionary history of the european whitefish coregonus lavaretus l species complex as inferred from mtdna phylogeography and Gill Raker numbers
Molecular Ecology, 2005Co-Authors: Kjartan Ostbye, Louis Bernatchez, T F Naesje, K J M Himberg, Kjetil HindarAbstract:We compared mitochondrial DNA and Gill-Raker number variation in populations of the European whitefish Coregonus lavaretus (L.) species complex to illuminate their evolutionary history, and discuss mechanisms behind diversification. Using single-strand conformation polymorphism (SSCP) and sequencing 528 bp of combined parts of the cytochrome oxidase b (cyt b ) and NADH dehydrogenase subunit 3 (ND3) mithochondrial DNA (mtDNA) regions, we documented phylogeographic relationships among populations and phylogeny of mtDNA haplotypes. Demographic events behind geographical distribution of haplotypes were inferred using nested clade analysis (NCA) and mismatch distribution. Concordance between operational taxonomical groups, based on Gill-Raker numbers, and mtDNA patterns was tested. Three major mtDNA clades were resolved in Europe: a North European clade from northwest Russia to Denmark, a Siberian clade from the Arctic Sea to southwest Norway, and a South European clade from Denmark to the European Alps, reflecting occupation in different glacial refugia. Demographic events inferred from NCA were isolation by distance, range expansion, and fragmentation. Mismatch analysis suggested that clades which colonized Fennoscandia and the Alps expanded in population size 24 500–5800 years before present, with minute female effective population sizes, implying small founder populations during colonization. Gill-Raker counts did not commensurate with hierarchical mtDNA clades, and poorly with haplotypes, suggesting recent origin of Gill-Raker variation. Whitefish designations based on Gill-Raker numbers were not associated with ancient clades. Lack of congruence in morphology and evolutionary lineages implies that the taxonomy of this species complex should be reconsidered.
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Evolutionary history of the European whitefish Coregonus lavaretus (L.) species complex as inferred from mtDNA phylogeography and Gill‐Raker numbers
Molecular Ecology, 2005Co-Authors: Kjartan Ostbye, Louis Bernatchez, T F Naesje, K J M Himberg, Kjetil HindarAbstract:We compared mitochondrial DNA and Gill-Raker number variation in populations of the European whitefish Coregonus lavaretus (L.) species complex to illuminate their evolutionary history, and discuss mechanisms behind diversification. Using single-strand conformation polymorphism (SSCP) and sequencing 528 bp of combined parts of the cytochrome oxidase b (cyt b ) and NADH dehydrogenase subunit 3 (ND3) mithochondrial DNA (mtDNA) regions, we documented phylogeographic relationships among populations and phylogeny of mtDNA haplotypes. Demographic events behind geographical distribution of haplotypes were inferred using nested clade analysis (NCA) and mismatch distribution. Concordance between operational taxonomical groups, based on Gill-Raker numbers, and mtDNA patterns was tested. Three major mtDNA clades were resolved in Europe: a North European clade from northwest Russia to Denmark, a Siberian clade from the Arctic Sea to southwest Norway, and a South European clade from Denmark to the European Alps, reflecting occupation in different glacial refugia. Demographic events inferred from NCA were isolation by distance, range expansion, and fragmentation. Mismatch analysis suggested that clades which colonized Fennoscandia and the Alps expanded in population size 24 500–5800 years before present, with minute female effective population sizes, implying small founder populations during colonization. Gill-Raker counts did not commensurate with hierarchical mtDNA clades, and poorly with haplotypes, suggesting recent origin of Gill-Raker variation. Whitefish designations based on Gill-Raker numbers were not associated with ancient clades. Lack of congruence in morphology and evolutionary lineages implies that the taxonomy of this species complex should be reconsidered.
Per-arne Amundsen - One of the best experts on this subject based on the ideXlab platform.
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Diversifying selection drives parallel evolution of Gill Raker number and body size along the speciation continuum of European whitefish
Ecology and Evolution, 2018Co-Authors: Katja Häkli, Per-arne Amundsen, Kimmo K. Kahilainen, Kjartan Ostbye, Kim PræbelAbstract:Adaptive radiation is the evolution of ecological and phenotypical diversity. It arises via ecological opportunity that promotes the exploration of underutilized or novel niches mediating specialization and reproductive isolation. The assumed precondition for rapid local adaptation is diversifying natural selection, but random genetic drift could also be a major driver of this process. We used 27 populations of European whitefish (Coregonus lavaretus) from nine lakes distributed in three neighboring subarctic watercourses in northern Fennoscandia as a model to test the importance of random drift versus diversifying natural selection for parallel evolution of adaptive phenotypic traits. We contrasted variation for two key adaptive phenotypic traits correlated with resource utilization of polymorphic fish; the number of Gill Rakers and the total length of fish, with the posterior distribution of neutral genetic differentiation from 13 microsatellite loci, to test whether the observed phenotypic divergence could be achieved by random genetic drift alone. Our results show that both traits have been under diversifying selection and that the evolution of these morphs has been driven by isolation through habitat adaptations. We conclude that diversifying selection acting on Gill Raker number and body size has played a significant role in the ongoing adaptive radiation of European whitefish morphs in this region.
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Speciation Reversal in European Whitefish (Coregonus lavaretus (L.)) Caused by Competitor Invasion
2016Co-Authors: Shripathi Bhat, Per-arne Amundsen, Rune Knudsen, Louis Bernatchez, Karl Øystein Gjell, Svein-erik Fevolden, Kim PræbelAbstract:Invasion of exotic species has caused the loss of biodiversity and imparts evolutionary and ecological changes in the introduced systems. In northern Fennoscandia, European whitefish (Coregonus lavaretus (L.)) is a highly polymorphic species displaying adaptive radiations into partially reproductively isolated and thus genetically differentiated sympatric morphs utilizing the planktivorous and benthivorous food niche in many lakes. In 1993, Lake Skrukkebukta was invaded by vendace (Coregonus albula (L.)) which is a zooplanktivorous specialist. The vendace displaced the densely Rakered whitefish from its preferred pelagic niche to the benthic habitat harbouring the large sparsely Rakered whitefish. In this study, we investigate the potential influence of the vendace invasion on the breakdown of reproductive isolation between the two whitefish morphs. We inferred the genotypic and phenotypic differentiation between the two morphs collected at the arrival (1993) and 15 years after (2008) the vendace invasion using 16 microsatellite loci and Gill Raker numbers, the most distinctive adaptive phenotypic trait between them. The comparison of Gill Raker number distributions revealed two modes growing closer over 15 years following the invasion. Bayesian analyses of genotypes revealed that the two genetically distinct whitefish morphs that existed in 1993 had collapsed into a single population in 2008. The decline in association between the Gill Raker numbers and admixture values over 15 years corroborates the findings from the Bayesian analysis. Our study thus suggests an apparent decrease of reproductive isolation in a morph-pair of European whitefish within 15 years (.
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The role of Gill Raker number variability in adaptive radiation of coregonid fish
Evolutionary Ecology, 2011Co-Authors: Kimmo K. Kahilainen, Rune Knudsen, Anna Siwertsson, Karl Ø. Gjelland, Thomas Bøhn, Per-arne AmundsenAbstract:Gill Raker divergence is a general pattern in adaptive radiations of postglacial fish, but few studies have addressed the adaptive significance of this morphological trait in foraging and eco-evolutionary interactions among predator and prey. Here, a set of subarctic lakes along a diversifying gradient of coregonids was used as the natural setting to explore correlations between Gill Raker numbers and planktivory as well as the impact of coregonid radiation on zooplankton communities. Results from 19 populations covering most of the total Gill Raker number gradient of the genus Coregonus , confirm that the number of Gill Rakers has a central role in determining the foraging ability towards zooplankton prey. Both at the individual and population levels, Gill Raker number was correlated with pelagic niche use and the size of utilized zooplankton prey. Furthermore, the average body size and the abundance and diversity of the zooplankton community decreased with the increasing diversity of coregonids. We argue that zooplankton feeding leads to an eco-evolutionary feedback loop that may further shape the Gill Raker morphology since natural selection intensifies under resource competition for depleted prey communities. Eco-evolutionary interactions may thus have a central role creating and maintaining the divergence of coregonid morphs in postglacial lakes.
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Resource competition and interactive segregation between sympatric whitefish morphs
Annales Zoologici Fennici, 2004Co-Authors: Per-arne Amundsen, Rune Knudsen, Anders Klemetsen, Roar KristoffersenAbstract:Two whitefish morphs have been identified in lakes in northern Norway from a bimodal distribution of Gill Raker numbers: a sparsely- and a densely-Rakered. Habitat choice and feeding ecology of whitefish were studied in five lakes with the two morphs living in sympatry, and in five lakes harbouring only the sparsely-Rakered morph. In sympatry, the two whitefish morphs exhibited a strict niche segregation, the sparsely-Rakered morph mainly residing in the littoral zone feeding on zoobenthos, whereas the densely-Rakered morph predominantly fed on zooplankton and dominated in the pelagic zone. In allopatry, however, the densely-Rakered morph exhibited a larger niche width, utilising both the benthic and pelagic habitats and having a diet that included both zoobenthos and zooplankton. Thus, in sympatry with densely-Rakered whitefish, the sparsely-Rakered morph appears to be relegated from the pelagic zone, resulting in an interactive segregation due to resource competition between the two morphs.
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Gill Raker morphology and feeding ecology of two sympatric morphs of European whitefish (Coregonus lavaretus)
Annales Zoologici Fennici, 2004Co-Authors: Per-arne Amundsen, Thomas Bøhn, Gry H. VagaAbstract:European whitefish is a polymorphic species where different morphs often are identified by differences in their Gill Raker numbers. Gill Rakers may play an important role in food-particle retention, particularly with respect to zooplankton feeding. Possible associations between feeding ecology and Gill Raker number and morphology were studied in European whitefish in the Pasvik watercourse. The numbers of Gill Rakers exhibited a bimodal distribution pattern, demonstrating the presence of two sympatric forms, including a sparsely-Rakered morph with 18-30 and a densely-Rakered morph with 28-42 Rakers. The morphology of the Gill Rakers was correlated to the Raker number and exhibited distinct differences between the morphs; sparsely-Rakered whitefish having shorter, thicker and less densely packed Rakers than the densely-Rakered morph. Differences in habitat choice and trophic ecology between the two morphs appeared to be correlated to Gill Raker number and morphology. Densely-Rakered whitefish exhibited a diet dominated by zooplankton and other pelagic prey, whereas the sparsely-Rakered morph mainly fed on zoobenthos. Within the morphs, however, the feeding ecology of individual fish was not correlated with number and morphology of the Gill Rakers. Thus, whereas Gill Raker number and morphology appear to be a reliable marker for identifying ecologically and genetically different European whitefish morphs, the functional role with respect to the feeding performance of individual fish is less obvious.
Kjetil Hindar - One of the best experts on this subject based on the ideXlab platform.
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evolutionary history of the european whitefish coregonus lavaretus l species complex as inferred from mtdna phylogeography and Gill Raker numbers
Molecular Ecology, 2005Co-Authors: Kjartan Ostbye, Louis Bernatchez, T F Naesje, K J M Himberg, Kjetil HindarAbstract:We compared mitochondrial DNA and Gill-Raker number variation in populations of the European whitefish Coregonus lavaretus (L.) species complex to illuminate their evolutionary history, and discuss mechanisms behind diversification. Using single-strand conformation polymorphism (SSCP) and sequencing 528 bp of combined parts of the cytochrome oxidase b (cyt b ) and NADH dehydrogenase subunit 3 (ND3) mithochondrial DNA (mtDNA) regions, we documented phylogeographic relationships among populations and phylogeny of mtDNA haplotypes. Demographic events behind geographical distribution of haplotypes were inferred using nested clade analysis (NCA) and mismatch distribution. Concordance between operational taxonomical groups, based on Gill-Raker numbers, and mtDNA patterns was tested. Three major mtDNA clades were resolved in Europe: a North European clade from northwest Russia to Denmark, a Siberian clade from the Arctic Sea to southwest Norway, and a South European clade from Denmark to the European Alps, reflecting occupation in different glacial refugia. Demographic events inferred from NCA were isolation by distance, range expansion, and fragmentation. Mismatch analysis suggested that clades which colonized Fennoscandia and the Alps expanded in population size 24 500–5800 years before present, with minute female effective population sizes, implying small founder populations during colonization. Gill-Raker counts did not commensurate with hierarchical mtDNA clades, and poorly with haplotypes, suggesting recent origin of Gill-Raker variation. Whitefish designations based on Gill-Raker numbers were not associated with ancient clades. Lack of congruence in morphology and evolutionary lineages implies that the taxonomy of this species complex should be reconsidered.
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Evolutionary history of the European whitefish Coregonus lavaretus (L.) species complex as inferred from mtDNA phylogeography and Gill‐Raker numbers
Molecular Ecology, 2005Co-Authors: Kjartan Ostbye, Louis Bernatchez, T F Naesje, K J M Himberg, Kjetil HindarAbstract:We compared mitochondrial DNA and Gill-Raker number variation in populations of the European whitefish Coregonus lavaretus (L.) species complex to illuminate their evolutionary history, and discuss mechanisms behind diversification. Using single-strand conformation polymorphism (SSCP) and sequencing 528 bp of combined parts of the cytochrome oxidase b (cyt b ) and NADH dehydrogenase subunit 3 (ND3) mithochondrial DNA (mtDNA) regions, we documented phylogeographic relationships among populations and phylogeny of mtDNA haplotypes. Demographic events behind geographical distribution of haplotypes were inferred using nested clade analysis (NCA) and mismatch distribution. Concordance between operational taxonomical groups, based on Gill-Raker numbers, and mtDNA patterns was tested. Three major mtDNA clades were resolved in Europe: a North European clade from northwest Russia to Denmark, a Siberian clade from the Arctic Sea to southwest Norway, and a South European clade from Denmark to the European Alps, reflecting occupation in different glacial refugia. Demographic events inferred from NCA were isolation by distance, range expansion, and fragmentation. Mismatch analysis suggested that clades which colonized Fennoscandia and the Alps expanded in population size 24 500–5800 years before present, with minute female effective population sizes, implying small founder populations during colonization. Gill-Raker counts did not commensurate with hierarchical mtDNA clades, and poorly with haplotypes, suggesting recent origin of Gill-Raker variation. Whitefish designations based on Gill-Raker numbers were not associated with ancient clades. Lack of congruence in morphology and evolutionary lineages implies that the taxonomy of this species complex should be reconsidered.