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John E Brittain - One of the best experts on this subject based on the ideXlab platform.
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diet overlap between introduced european minnow phoxinus phoxinus and young brown trout salmo trutta in the lake ovre heimdalsvatn a result of abundant resources or forced niche overlap
Hydrobiologia, 2010Co-Authors: Jon Museth, Reidar Borgstrom, John E BrittainAbstract:A study of the diet of native brown trout (Salmo trutta) parr and introduced European minnow (phoxinus phoxinus) in the subalpine lake, Ovre Heimdalsvatn, showed that the two species had considerable dietary overlap, both in the littoral zone and in the outlet of the lake. Chironomidae constituted a substantial proportion of the diet of the two species in both habitats. The results indicated that both zooplankton (Cladocera) and large macroinvertebrates (EPT-species) made up a higher proportion of the minnow diet in the early phase of the minnow establishment (1975–1977) than later, and that the significance of small macroinvertebrates (Chironomidae) as prey has increased during the same period. Dietary analysis of the sympatric brown trout and minnow population in Ovre Heimdalsvatn does not provide a definitive conclusion about the degree of competition between the two species. However, together with the findings in other studies in Ovre Heimdalsvatn that have documented reduced recruitment and individual growth of brown trout, decreased individual growth of minnows and a marked decline in the density of large crustaceans (Lepidurus arcticus and Gammarus lacustris) in the shallow littoral of the lake during the last decades indicates that competitive interactions between the two species are likely. This is probably an example of the competition between two fish species with a high degree of dietary overlap when living in sympatry, most likely caused by absence of alternative prey and alternative habitats due to the high predation risk for both brown trout parr and minnows in deeper parts and in the open waters of the lake.
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the brown trout salmo trutta in the lake ovre heimdalsvatn long term changes in population dynamics due to exploitation and the invasive species european minnow phoxinus phoxinus
Hydrobiologia, 2010Co-Authors: Reidar Borgstrom, Jon Museth, John E BrittainAbstract:Studies of the brown trout (Salmo trutta) population in the Norwegian subalpine lake, Ovre Heimdalsvatn, over a 50-year period have revealed major changes in population dynamics. In 1958, the population density was high, with individuals stagnating in growth at lengths below 30 cm. After heavy exploitation during the years 1958–1969, the number of older fish declined substantially, and growth rates increased significantly. Since 1969, the European minnow (phoxinus phoxinus) have been observed in the lake, with increasing densities from 1977–1978 to 1999–2000. The age structure of the brown trout population has changed markedly from the 1960s to the period 1993–2006. Annual recruitment significantly declined, from an average number of 3746 individuals in age-class 4 during the period 1958–1966 to an average of 1668 during the period 1993–2006. However, due to lower exploitation rates, the number of old fish was significantly higher in the latter period. The summer diet of brown trout has changed substantially from a dominance of the large crustaceans Lepidurus arcticus and Gammarus lacustris to a high occurrence of European minnows, while L. arcticus has become practically absent from the diet. There was a negative relationship between brown trout biomass and annual length increment. However, despite a brown trout biomass at the same level during the years 1993–2006 as in the 1960s, annual individual growth rates have significantly declined. The reduced recruitment and reduced annual growth rates of the brown trout, as well as changes in the diet, are most likely related to the introduction and establishment of the invasive species, the European minnow.
Reidar Borgstrom - One of the best experts on this subject based on the ideXlab platform.
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the importance of size and growth rate in determining mercury concentrations in european minnow phoxinus phoxinus and brown trout salmo trutta in the subalpine lake ovre heimdalsvatn
Hydrobiologia, 2010Co-Authors: Marthe Torunn Solhaug Jenssen, Reidar Borgstrom, Brit Salbu, Bjorn Olav RosselandAbstract:The alien fish species, European minnow (phoxinus phoxinus), was recorded in the mountain lake, Ovre Heimdalsvatn, southern Norway, for the first time in 1969. After some years minnows were observed in the diet of brown trout (Salmo trutta). In 2006, brown trout had significantly higher δ15N values than European minnow, indicating that brown trout holds the top trophic position in the lake food web. The δ15N signatures of brown trout were significantly correlated to fish size, age and mercury concentration, while δ15N signatures in minnows did not show any change with fish size, age and mercury concentrations, indicating that European minnow remain at the same trophic level throughout the life history. The mercury concentrations (mg kg−1 w.w.) in brown trout and minnows were in the range 0.014–0.093 and 0.014–0.16, respectively. For both species, positive relationships between total mercury concentrations and fish length, weight and age were found. Although European minnow was found as prey in brown trout stomachs, minnow had significantly higher mercury concentrations than brown trout. It is most likely that the higher mercury concentrations in the European minnow are due to the high metabolic rate, with more energy spent on maintenance than on growth as a consequence of its small size and very low annual growth rate compared to brown trout. Changes in population densities of both brown trout and European minnow may influence their habitat use, feeding preferences and metabolism, and may thus potentially lead to changes in the mercury loads of both species.
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diet overlap between introduced european minnow phoxinus phoxinus and young brown trout salmo trutta in the lake ovre heimdalsvatn a result of abundant resources or forced niche overlap
Hydrobiologia, 2010Co-Authors: Jon Museth, Reidar Borgstrom, John E BrittainAbstract:A study of the diet of native brown trout (Salmo trutta) parr and introduced European minnow (phoxinus phoxinus) in the subalpine lake, Ovre Heimdalsvatn, showed that the two species had considerable dietary overlap, both in the littoral zone and in the outlet of the lake. Chironomidae constituted a substantial proportion of the diet of the two species in both habitats. The results indicated that both zooplankton (Cladocera) and large macroinvertebrates (EPT-species) made up a higher proportion of the minnow diet in the early phase of the minnow establishment (1975–1977) than later, and that the significance of small macroinvertebrates (Chironomidae) as prey has increased during the same period. Dietary analysis of the sympatric brown trout and minnow population in Ovre Heimdalsvatn does not provide a definitive conclusion about the degree of competition between the two species. However, together with the findings in other studies in Ovre Heimdalsvatn that have documented reduced recruitment and individual growth of brown trout, decreased individual growth of minnows and a marked decline in the density of large crustaceans (Lepidurus arcticus and Gammarus lacustris) in the shallow littoral of the lake during the last decades indicates that competitive interactions between the two species are likely. This is probably an example of the competition between two fish species with a high degree of dietary overlap when living in sympatry, most likely caused by absence of alternative prey and alternative habitats due to the high predation risk for both brown trout parr and minnows in deeper parts and in the open waters of the lake.
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the brown trout salmo trutta in the lake ovre heimdalsvatn long term changes in population dynamics due to exploitation and the invasive species european minnow phoxinus phoxinus
Hydrobiologia, 2010Co-Authors: Reidar Borgstrom, Jon Museth, John E BrittainAbstract:Studies of the brown trout (Salmo trutta) population in the Norwegian subalpine lake, Ovre Heimdalsvatn, over a 50-year period have revealed major changes in population dynamics. In 1958, the population density was high, with individuals stagnating in growth at lengths below 30 cm. After heavy exploitation during the years 1958–1969, the number of older fish declined substantially, and growth rates increased significantly. Since 1969, the European minnow (phoxinus phoxinus) have been observed in the lake, with increasing densities from 1977–1978 to 1999–2000. The age structure of the brown trout population has changed markedly from the 1960s to the period 1993–2006. Annual recruitment significantly declined, from an average number of 3746 individuals in age-class 4 during the period 1958–1966 to an average of 1668 during the period 1993–2006. However, due to lower exploitation rates, the number of old fish was significantly higher in the latter period. The summer diet of brown trout has changed substantially from a dominance of the large crustaceans Lepidurus arcticus and Gammarus lacustris to a high occurrence of European minnows, while L. arcticus has become practically absent from the diet. There was a negative relationship between brown trout biomass and annual length increment. However, despite a brown trout biomass at the same level during the years 1993–2006 as in the 1960s, annual individual growth rates have significantly declined. The reduced recruitment and reduced annual growth rates of the brown trout, as well as changes in the diet, are most likely related to the introduction and establishment of the invasive species, the European minnow.
Luca Fumagalli - One of the best experts on this subject based on the ideXlab platform.
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aflpdata_Pyrenees_Collin_Fumagalli
2016Co-Authors: Hélène Collin, Luca FumagalliAbstract:This table contains 1930 AFLP markers from phoxinus phoxinus from the Pyrenees. Population number, and individual ID are indicated. Individual IDs correspond to the first 2 letters of the population name, followed by the individual number. AFLP data are coded as: 0=recessive allele, 1= dominant allel
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aflpdata_Collin&Fumagalli
2016Co-Authors: Hélène Collin, Luca FumagalliAbstract:This table contains 1930 AFLP markers from phoxinus phoxinus. Population number, and individual ID are indicated. Individual IDs correspond to the first 2 letters of the population name, followed by the individual number. AFLP data are coded as: 0=recessive allele, 1= dominant allel
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The role of geography and ecology in shaping repeated patterns of morphological and genetic differentiation between European minnows (phoxinus phoxinus) from the Pyrenees and the Alps
Biological Journal of the Linnean Society, 2015Co-Authors: Hélène Collin, Luca FumagalliAbstract:Neutral and selective processes c an drive repeated patterns of evolu tion in dif ferent groups of populationsexp eriencing similar ecol ogica l gradients. In this paper, we used a combinat ion of nucl ear and mitochondrialDNA markers, as well as geometric morphometrics, to investigate repeated patterns of morphological andgenetic divergence of E uropean minnows in two mountain ranges : the Pyrenees and the Al ps. Europeanminnows (phoxinus phoxinus) are cyprinid fish i nha bitin g most freshwater bodies in Europe, including those indifferent mountain r anges that could act as major geographical barriers to gene flow. We explored patterns ofP. phoxinus phenotypic and genetic di versi fication along a gradi ent of alti tude common to the two mountainranges, and tested for isolation by distance (IBD), isolation by environment (IBE) and isolation by adaptation(IBA). The results indicated that populations from the Pyr enees a nd the Alps bel ong to two well differentiated,reciprocally monophyletic mt DNA lineages. Substantial genetic differentiation due to geographical isolationwithin and between populations from the Pyrenees and the Alps was also found using rapidly evolving AFLPsmarkers (isolation by distance or IBD), as well as morphological differences between mountain ranges. Als o,morphology varied strong ly with elevation and so did genetic differentiation to a lower extent. Despitemoderate evidence for IBE and IBA, and therefore of repeated evolution, substantial population heterogeneitywas found at the genetic level, suggesting that selection and population specific genetic drift act in concert toaffect genetic divergence.
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combining molecular evolution and environmental genomics to unravel adaptive processes of mhc class iib diversity in european minnows phoxinus phoxinus
Ecology and Evolution, 2013Co-Authors: Hélène Collin, Reto Burri, Fabien Comtesse, Luca FumagalliAbstract:Host-pathogen interactions are a major evolutionary force promoting local adaptation. Genes of the major histocompatibility complex (MHC) represent unique candidates to investigate evolutionary processes driving local adaptation to parasite communities. The present study aimed at identifying the relative roles of neutral and adaptive processes driving the evolution of MHC class IIB (MHCIIB) genes in natural populations of European minnows (phoxinus phoxinus). To this end, we isolated and genotyped exon 2 of two MHCIIB gene duplicates (DAB1 and DAB3) and 1665 amplified fragment length polymorphism (AFLP) markers in nine populations, and characterized local bacterial communities by 16S rDNA barcoding using 454 amplicon sequencing. Both MHCIIB loci exhibited signs of historical balancing selection. Whereas genetic differentiation exceeded that of neutral markers at both loci, the populations' genetic diversities were positively correlated with local pathogen diversities only at DAB3. Overall, our results suggest pathogen-mediated local adaptation in European minnows at both MHCIIB loci. While at DAB1 selection appears to favor different alleles among populations, this is only partially the case in DAB3, which appears to be locally adapted to pathogen communities in terms of genetic diversity. These results provide new insights into the importance of host-pathogen interactions in driving local adaptation in the European minnow, and highlight that the importance of adaptive processes driving MHCIIB gene evolution may differ among duplicates within species, presumably as a consequence of alternative selective regimes or different genomic context.
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Evidence for morphological and adaptive genetic divergence between lake and stream habitats in European minnows (phoxinus phoxinus, Cyprinidae)
Molecular Ecology, 2011Co-Authors: Hélène Collin, Luca FumagalliAbstract:Natural selection drives local adaptation, potentially even at small temporal and spatial scales. As a result, adaptive genetic and phenotypic divergence can occur among populations living in different habitats. We investigated patterns of differentiation between contrasting lake and stream habitats in the cyprinid fish European minnow (phoxinus phoxinus) at both the morphological and genomic levels using geometric morphometrics and AFLP markers, respectively. We also used a spatial correlative approach to identify AFLP loci associated with environmental variables representing potential selective forces responsible for adaptation to divergent habitats. Our results identified different morphologies between lakes and streams, with lake fish presenting a deeper body and caudal peduncle compared to stream fish. Body shape variation conformed to a priori predictions concerning biomechanics and swimming performance in lakes vs. streams. Moreover, morphological differentiation was found to be associated with several environmental variables, which could impose selection on body and caudal peduncle shape. We found adaptive genetic divergence between these contrasting habitats in the form of 'outlier' loci (2.9%) whose genetic divergence exceeded neutral expectations. We also detected additional loci (6.6%) not associated with habitat type (lake vs. stream), but contributing to genetic divergence between populations. Specific environmental variables related to trophic dynamics, landscape topography and geography were associated with several neutral and outlier loci. These results provide new insights into the morphological divergence and genetic basis of adaptation to differentiated habitats.
Jon Museth - One of the best experts on this subject based on the ideXlab platform.
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diet overlap between introduced european minnow phoxinus phoxinus and young brown trout salmo trutta in the lake ovre heimdalsvatn a result of abundant resources or forced niche overlap
Hydrobiologia, 2010Co-Authors: Jon Museth, Reidar Borgstrom, John E BrittainAbstract:A study of the diet of native brown trout (Salmo trutta) parr and introduced European minnow (phoxinus phoxinus) in the subalpine lake, Ovre Heimdalsvatn, showed that the two species had considerable dietary overlap, both in the littoral zone and in the outlet of the lake. Chironomidae constituted a substantial proportion of the diet of the two species in both habitats. The results indicated that both zooplankton (Cladocera) and large macroinvertebrates (EPT-species) made up a higher proportion of the minnow diet in the early phase of the minnow establishment (1975–1977) than later, and that the significance of small macroinvertebrates (Chironomidae) as prey has increased during the same period. Dietary analysis of the sympatric brown trout and minnow population in Ovre Heimdalsvatn does not provide a definitive conclusion about the degree of competition between the two species. However, together with the findings in other studies in Ovre Heimdalsvatn that have documented reduced recruitment and individual growth of brown trout, decreased individual growth of minnows and a marked decline in the density of large crustaceans (Lepidurus arcticus and Gammarus lacustris) in the shallow littoral of the lake during the last decades indicates that competitive interactions between the two species are likely. This is probably an example of the competition between two fish species with a high degree of dietary overlap when living in sympatry, most likely caused by absence of alternative prey and alternative habitats due to the high predation risk for both brown trout parr and minnows in deeper parts and in the open waters of the lake.
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the brown trout salmo trutta in the lake ovre heimdalsvatn long term changes in population dynamics due to exploitation and the invasive species european minnow phoxinus phoxinus
Hydrobiologia, 2010Co-Authors: Reidar Borgstrom, Jon Museth, John E BrittainAbstract:Studies of the brown trout (Salmo trutta) population in the Norwegian subalpine lake, Ovre Heimdalsvatn, over a 50-year period have revealed major changes in population dynamics. In 1958, the population density was high, with individuals stagnating in growth at lengths below 30 cm. After heavy exploitation during the years 1958–1969, the number of older fish declined substantially, and growth rates increased significantly. Since 1969, the European minnow (phoxinus phoxinus) have been observed in the lake, with increasing densities from 1977–1978 to 1999–2000. The age structure of the brown trout population has changed markedly from the 1960s to the period 1993–2006. Annual recruitment significantly declined, from an average number of 3746 individuals in age-class 4 during the period 1958–1966 to an average of 1668 during the period 1993–2006. However, due to lower exploitation rates, the number of old fish was significantly higher in the latter period. The summer diet of brown trout has changed substantially from a dominance of the large crustaceans Lepidurus arcticus and Gammarus lacustris to a high occurrence of European minnows, while L. arcticus has become practically absent from the diet. There was a negative relationship between brown trout biomass and annual length increment. However, despite a brown trout biomass at the same level during the years 1993–2006 as in the 1960s, annual individual growth rates have significantly declined. The reduced recruitment and reduced annual growth rates of the brown trout, as well as changes in the diet, are most likely related to the introduction and establishment of the invasive species, the European minnow.
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The history of the minnow phoxinus phoxinus (L.) in Norway: from harmless species to pest
Journal of Fish Biology, 2007Co-Authors: Jon Museth, Trygve Hesthagen, Odd Terje Sandlund, Eva B. Thorstad, Ola UgedalAbstract:The causes, effects and extent of minnow phoxinus phoxinus introductions in Norway are reviewed to assess why the introductions have had severe effects, especially where brown trout Salmo trutta is the only fish species present. The natural distribution of minnow in Norway was mainly restricted to low altitude localities in the south-eastern part of the country and in some northern areas. The distribution area expanded considerably throughout the 1900s, especially in mountain areas, due in part to the use of minnows as live bait for angling. Although minnow densities do not seem unusually high in the relatively complex fish communities of its native range, the species can achieve very high population densities when introduced to communities with few fish species, such as in the numerous recently invaded lakes where brown trout was the only fish species present. The dense minnow populations in these lakes appear to have led to reduced recruitment and growth rates in the brown trout, with abundances on average 35% lower in lakes where minnow has been introduced. The success of minnow in harsh habitats demonstrates their phenotypic and ecological plasticity, but also implies that their original distribution in Norway was restricted by early immigration history and not by environmental limitations. This suggests that human-assisted spread of the species could have strong adverse effects in Scandinavia lakes of low fish species richness.
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Effects of Ligula intestinalis on habitat use, predation risk and catchability in European minnows
Journal of Fish Biology, 2001Co-Authors: Jon MusethAbstract:The frequency of infection with Ligula intestinalis (Cestoda) in European minnow phoxinus phoxinus, in a subalpine lake in Eastern Norway, did not differ between vegetated shoreline, exposed shoreline and non-vegetated localities >50 m from the shoreline. There was no difference in the vertical distribution of infected and uninfected individuals. The frequency of infection was higher among minnows in brown trout Salmo trutta stomachs than among those obtained by gillnets and minnow traps, suggesting that brown trout selectively preyed on infected minnows. Prevalence of infection decreased with increasing fish size, probably due to selective mortality among parasitized individuals. Within a given length-class, minnows captured by different sections of multi-mesh gillnets showed a significant increase in the frequency of infection with increasing mesh-size. Apparently, parasitized individuals had a higher catchability in gillnets due to increased girth caused by the plerocercoid in the body cavity. This may partly explain why the observed prevalence of infection was several times higher among minnows captured by gillnets than by minnow traps.
Hélène Collin - One of the best experts on this subject based on the ideXlab platform.
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aflpdata_Pyrenees_Collin_Fumagalli
2016Co-Authors: Hélène Collin, Luca FumagalliAbstract:This table contains 1930 AFLP markers from phoxinus phoxinus from the Pyrenees. Population number, and individual ID are indicated. Individual IDs correspond to the first 2 letters of the population name, followed by the individual number. AFLP data are coded as: 0=recessive allele, 1= dominant allel
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aflpdata_Collin&Fumagalli
2016Co-Authors: Hélène Collin, Luca FumagalliAbstract:This table contains 1930 AFLP markers from phoxinus phoxinus. Population number, and individual ID are indicated. Individual IDs correspond to the first 2 letters of the population name, followed by the individual number. AFLP data are coded as: 0=recessive allele, 1= dominant allel
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The role of geography and ecology in shaping repeated patterns of morphological and genetic differentiation between European minnows (phoxinus phoxinus) from the Pyrenees and the Alps
Biological Journal of the Linnean Society, 2015Co-Authors: Hélène Collin, Luca FumagalliAbstract:Neutral and selective processes c an drive repeated patterns of evolu tion in dif ferent groups of populationsexp eriencing similar ecol ogica l gradients. In this paper, we used a combinat ion of nucl ear and mitochondrialDNA markers, as well as geometric morphometrics, to investigate repeated patterns of morphological andgenetic divergence of E uropean minnows in two mountain ranges : the Pyrenees and the Al ps. Europeanminnows (phoxinus phoxinus) are cyprinid fish i nha bitin g most freshwater bodies in Europe, including those indifferent mountain r anges that could act as major geographical barriers to gene flow. We explored patterns ofP. phoxinus phenotypic and genetic di versi fication along a gradi ent of alti tude common to the two mountainranges, and tested for isolation by distance (IBD), isolation by environment (IBE) and isolation by adaptation(IBA). The results indicated that populations from the Pyr enees a nd the Alps bel ong to two well differentiated,reciprocally monophyletic mt DNA lineages. Substantial genetic differentiation due to geographical isolationwithin and between populations from the Pyrenees and the Alps was also found using rapidly evolving AFLPsmarkers (isolation by distance or IBD), as well as morphological differences between mountain ranges. Als o,morphology varied strong ly with elevation and so did genetic differentiation to a lower extent. Despitemoderate evidence for IBE and IBA, and therefore of repeated evolution, substantial population heterogeneitywas found at the genetic level, suggesting that selection and population specific genetic drift act in concert toaffect genetic divergence.
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combining molecular evolution and environmental genomics to unravel adaptive processes of mhc class iib diversity in european minnows phoxinus phoxinus
Ecology and Evolution, 2013Co-Authors: Hélène Collin, Reto Burri, Fabien Comtesse, Luca FumagalliAbstract:Host-pathogen interactions are a major evolutionary force promoting local adaptation. Genes of the major histocompatibility complex (MHC) represent unique candidates to investigate evolutionary processes driving local adaptation to parasite communities. The present study aimed at identifying the relative roles of neutral and adaptive processes driving the evolution of MHC class IIB (MHCIIB) genes in natural populations of European minnows (phoxinus phoxinus). To this end, we isolated and genotyped exon 2 of two MHCIIB gene duplicates (DAB1 and DAB3) and 1665 amplified fragment length polymorphism (AFLP) markers in nine populations, and characterized local bacterial communities by 16S rDNA barcoding using 454 amplicon sequencing. Both MHCIIB loci exhibited signs of historical balancing selection. Whereas genetic differentiation exceeded that of neutral markers at both loci, the populations' genetic diversities were positively correlated with local pathogen diversities only at DAB3. Overall, our results suggest pathogen-mediated local adaptation in European minnows at both MHCIIB loci. While at DAB1 selection appears to favor different alleles among populations, this is only partially the case in DAB3, which appears to be locally adapted to pathogen communities in terms of genetic diversity. These results provide new insights into the importance of host-pathogen interactions in driving local adaptation in the European minnow, and highlight that the importance of adaptive processes driving MHCIIB gene evolution may differ among duplicates within species, presumably as a consequence of alternative selective regimes or different genomic context.
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Evidence for morphological and adaptive genetic divergence between lake and stream habitats in European minnows (phoxinus phoxinus, Cyprinidae)
Molecular Ecology, 2011Co-Authors: Hélène Collin, Luca FumagalliAbstract:Natural selection drives local adaptation, potentially even at small temporal and spatial scales. As a result, adaptive genetic and phenotypic divergence can occur among populations living in different habitats. We investigated patterns of differentiation between contrasting lake and stream habitats in the cyprinid fish European minnow (phoxinus phoxinus) at both the morphological and genomic levels using geometric morphometrics and AFLP markers, respectively. We also used a spatial correlative approach to identify AFLP loci associated with environmental variables representing potential selective forces responsible for adaptation to divergent habitats. Our results identified different morphologies between lakes and streams, with lake fish presenting a deeper body and caudal peduncle compared to stream fish. Body shape variation conformed to a priori predictions concerning biomechanics and swimming performance in lakes vs. streams. Moreover, morphological differentiation was found to be associated with several environmental variables, which could impose selection on body and caudal peduncle shape. We found adaptive genetic divergence between these contrasting habitats in the form of 'outlier' loci (2.9%) whose genetic divergence exceeded neutral expectations. We also detected additional loci (6.6%) not associated with habitat type (lake vs. stream), but contributing to genetic divergence between populations. Specific environmental variables related to trophic dynamics, landscape topography and geography were associated with several neutral and outlier loci. These results provide new insights into the morphological divergence and genetic basis of adaptation to differentiated habitats.