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Leif Asbjorn Vollestad - 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, Annette Taugbol, Mark Ravinet, Chris Harrod, Ruben Alexander Pettersen, Louis Bernatchez, Leif Asbjorn VollestadAbstract: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). All Morphs belonged to one gene pool. The complete morph was larger than the low plated, with the partial morph intermediate. The number of lateral plates ranged 8–71, with means of 64.2 for complete, 40.3 for partial, and 14.9 for low plated morph. Stickleback δ15N was higher in the lower lake section, while δ13C was higher in the upper section. Stickleback isotopic values were greater in autumn. The low plated morph had larger variances in δ15N and δ13C than the other Morphs. Sticklebacks in the upper section had more T. gasterostei than in the lower section which had more Trematoda spp. Sticklebacks had less T. gasterostei, but more Trematoda spp. in autumn than spring. Sticklebacks with few and short rakers had more T. gasterostei, while sticklebacks with longer rakers had more Trematoda. spp. Stickleback with higher δ15N values had more T. gasterostei, while sticklebacks with higher δ15N and δ13C values had more Trematoda spp. The low plated morph had fewer Trematoda spp. than other Morphs. Trait-ecology associations may imply that the three lateral plate Morphs in the brackish water lagoon of Lake Engervann are experiencing ongoing divergent selection for niche and migratory life history strategies under high gene flow. As such, the brackish water zone may generally act as a generator of genomic diversity to be selected upon in the different environments where threespine sticklebacks can live.
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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, Annette Taugbol, Mark Ravinet, Chris Harrod, Ruben Alexander Pettersen, Louis Bernatchez, Leif Asbjorn VollestadAbstract: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; δ^15N, δ^13C, 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). Results All Morphs belonged to one gene pool. The complete morph was larger than the low plated, with the partial morph intermediate. The number of lateral plates ranged 8–71, with means of 64.2 for complete, 40.3 for partial, and 14.9 for low plated morph. Stickleback δ^15N was higher in the lower lake section, while δ^13C was higher in the upper section. Stickleback isotopic values were greater in autumn. The low plated morph had larger variances in δ^15N and δ^13C than the other Morphs. Sticklebacks in the upper section had more T. gasterostei than in the lower section which had more Trematoda spp. Sticklebacks had less T. gasterostei , but more Trematoda spp. in autumn than spring. Sticklebacks with few and short rakers had more T. gasterostei , while sticklebacks with longer rakers had more Trematoda . spp. Stickleback with higher δ^15N values had more T. gasterostei, while sticklebacks with higher δ^15N and δ^13C values had more Trematoda spp. The low plated morph had fewer Trematoda spp. than other Morphs. Conclusions Trait-ecology associations may imply that the three lateral plate Morphs in the brackish water lagoon of Lake Engervann are experiencing ongoing divergent selection for niche and migratory life history strategies under high gene flow. As such, the brackish water zone may generally act as a generator of genomic diversity to be selected upon in the different environments where threespine sticklebacks can live.
Kjartan Ostbye - 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, Annette Taugbol, Mark Ravinet, Chris Harrod, Ruben Alexander Pettersen, Louis Bernatchez, Leif Asbjorn VollestadAbstract: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; δ^15N, δ^13C, 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). Results All Morphs belonged to one gene pool. The complete morph was larger than the low plated, with the partial morph intermediate. The number of lateral plates ranged 8–71, with means of 64.2 for complete, 40.3 for partial, and 14.9 for low plated morph. Stickleback δ^15N was higher in the lower lake section, while δ^13C was higher in the upper section. Stickleback isotopic values were greater in autumn. The low plated morph had larger variances in δ^15N and δ^13C than the other Morphs. Sticklebacks in the upper section had more T. gasterostei than in the lower section which had more Trematoda spp. Sticklebacks had less T. gasterostei , but more Trematoda spp. in autumn than spring. Sticklebacks with few and short rakers had more T. gasterostei , while sticklebacks with longer rakers had more Trematoda . spp. Stickleback with higher δ^15N values had more T. gasterostei, while sticklebacks with higher δ^15N and δ^13C values had more Trematoda spp. The low plated morph had fewer Trematoda spp. than other Morphs. Conclusions Trait-ecology associations may imply that the three lateral plate Morphs in the brackish water lagoon of Lake Engervann are experiencing ongoing divergent selection for niche and migratory life history strategies under high gene flow. As such, the brackish water zone may generally act as a generator of genomic diversity to be selected upon in the different environments where threespine sticklebacks can live.
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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, Annette Taugbol, Mark Ravinet, Chris Harrod, Ruben Alexander Pettersen, Louis Bernatchez, Leif Asbjorn VollestadAbstract: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). All Morphs belonged to one gene pool. The complete morph was larger than the low plated, with the partial morph intermediate. The number of lateral plates ranged 8–71, with means of 64.2 for complete, 40.3 for partial, and 14.9 for low plated morph. Stickleback δ15N was higher in the lower lake section, while δ13C was higher in the upper section. Stickleback isotopic values were greater in autumn. The low plated morph had larger variances in δ15N and δ13C than the other Morphs. Sticklebacks in the upper section had more T. gasterostei than in the lower section which had more Trematoda spp. Sticklebacks had less T. gasterostei, but more Trematoda spp. in autumn than spring. Sticklebacks with few and short rakers had more T. gasterostei, while sticklebacks with longer rakers had more Trematoda. spp. Stickleback with higher δ15N values had more T. gasterostei, while sticklebacks with higher δ15N and δ13C values had more Trematoda spp. The low plated morph had fewer Trematoda spp. than other Morphs. Trait-ecology associations may imply that the three lateral plate Morphs in the brackish water lagoon of Lake Engervann are experiencing ongoing divergent selection for niche and migratory life history strategies under high gene flow. As such, the brackish water zone may generally act as a generator of genomic diversity to be selected upon in the different environments where threespine sticklebacks can live.
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ecological speciation in postglacial european whitefish rapid adaptive radiations into the littoral pelagic and profundal lake habitats
Ecology and Evolution, 2013Co-Authors: Kim Praebel, Anna Siwertsson, Markku Karhunen, Kjartan Ostbye, Stefano Peruzzi, Rune Knudsen, Kimmo K Kahilainen, Otso Ovaskainen, Sveinerik FevoldenAbstract:Understanding how a monophyletic lineage of a species diverges into several adaptive forms has received increased attention in recent years, but the underlying mechanisms in this process are still under debate. Postglacial fishes are excellent model organisms for exploring this process, especially the initial stages of ecological speciation, as postglacial lakes represent replicated discrete environments with variation in available niches. Here, we combine data of niche utilization, trophic morphology, and 17 microsatellite loci to investigate the diversification process of three sympatric European whitefish Morphs from three northern Fennoscandian lakes. The morphological divergence in the gill raker number among the whitefish Morphs was related to the utilization of different trophic niches and was associated with reproductive isolation within and across lakes. The intralacustrine comparison of whitefish Morphs showed that these systems represent two levels of adaptive divergence: (1) a consistent littoral–pelagic resource axis; and (2) a more variable littoral–profundal resource axis. The results also indicate that the profundal whitefish morph has diverged repeatedly from the ancestral littoral whitefish morph in sympatry in two different watercourses. In contrast, all the analyses performed revealed clustering of the pelagic whitefish Morphs across lakes suggesting parallel postglacial immigration with the littoral whitefish morph into each lake. Finally, the analyses strongly suggested that the trophic adaptive trait, number of gill rakers, was under diversifying selection in the different whitefish Morphs. Together, the results support a complex evolutionary scenario where ecological speciation acts, but where both allopatric (colonization history) and sympatric (within watercourse divergence) processes are involved.
Charles C Krueger - One of the best experts on this subject based on the ideXlab platform.
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among individual diet variation within a lake trout ecotype lack of stability of niche use
bioRxiv, 2020Co-Authors: William M Tonn, Louise Chavarie, Kimberly L Howland, Colin P Gallagher, Michael J Hansen, Andrew M Muir, Les N Harris, Charles C KruegerAbstract:Ecological opportunities present during colonization of novel environments can drive divergent selection on traits, resulting in specialization of Morphs to enhance efficient use of resources and, potentially, intraspecific divergence and ecological speciation. Thus, in an ecologically polymorphic species, differences in resource specialization should be found among Morphs, and homogeneity in resource use expected within a morph. Using the piscivorous lake trout morph, one of four Morphs in Great Bear Lake, we investigate whether specialization of trophic resources among individuals occurs within this single morph, which could indicate a potential for continued divergence. Four distinct dietary patterns of resource use within the piscivorous lake trout morph were detected from analyses of fatty acid composition. In general, feeding habits of different groups within the piscivorous morph were not associated with detectable morphological or genetic differentiation, suggesting that behavioral plasticity within individuals or behavioral differences among individuals may have caused the trophic variation within this morph. A low level of genetic differentiation indicated by variation at microsatellite loci was detected between exceptionally large-sized individuals (Giant sub-set) and other piscivorous individuals. Investigating a geologically young system that displays high levels of intraspecific diversity and focusing on dietary patterns of resource use variation of individuals suggested that individual specialization can occur within a trophic morph.
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trophic variation within a piscivorous lake trout morph from great bear lake canada the initial step toward ecological specialization
bioRxiv, 2019Co-Authors: Louise Chavarie, William M Tonn, Kimberly L Howland, Colin P Gallagher, Michael J Hansen, Andrew M Muir, Les N Harris, Charles C KruegerAbstract:Ecological opportunities present during colonization of novel environments can drive divergent selection on traits, resulting in specialization of Morphs to enhance efficient use of resources and, potentially, intraspecific divergence and ecological speciation. Thus, in an ecologically polymorphic species, differences in resource specialization should be found among Morphs, and homogeneity in resource use expected within a morph. Using the piscivorous lake trout morph, one of four Morphs in Great Bear Lake, we investigate whether specialization of trophic resources among individuals occurs within this single morph, which could indicate a potential for continued divergence. Four distinct dietary patterns of resource use within the piscivorous lake trout morph were detected from analyses of fatty acid composition. In general, feeding habits of different groups within the piscivorous morph were not associated with detectable morphological or genetic differentiation, suggesting that behavioral plasticity within individuals or behavioral differences among individuals may have caused the trophic variation within this morph. A low level of genetic differentiation indicated by variation at microsatellite loci was detected between exceptionally large-sized individuals (Giant sub-set) and other piscivorous individuals. Investigating a geologically young system that displays high levels of intraspecific diversity and focusing on dietary patterns of resource use variation of individuals suggested that individual specialization can occur within a trophic morph.
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if arctic charr salvelinus alpinus is the most diverse vertebrate what is the lake charr salvelinus namaycush
Fish and Fisheries, 2016Co-Authors: Andrew M Muir, Michael J Hansen, Charles R Bronte, Charles C KruegerAbstract:Teleost fishes are prominent vertebrate models of evolution, illustrated among old-world radiations by the Cichlidae of East African Great Lakes and new-world radiations by the circumpolar Arctic charr Salvelinus alpinus. Herein, we describe variation in lake charr S. namaycush morphology, life history, physiology and ecology, as another example of radiation. The lake charr is restricted to northern North America, where it originated from glacial refugia and diversified in large lakes. Shallow and deepwater Morphs arose in multiple lakes, with a large-bodied shallow-water ‘lean’ morph in shallow inshore depths, a small-bodied mid-water ‘humper’ morph on offshore shoals or banks, a robust, large-bodied moderate to deep-water ‘redfin’; morph and a large-bodied deep-water ‘siscowet’ morph at depths > 100 m. Eye position, gape size, and gillraker length and spacing adapted for feeding on different-sized prey, with piscivorous Morphs (leans, siscowets and presumably redfins) reaching larger asymptotic size than invertivorous Morphs (humpers). Lean Morphs are light in colour, whereas deepwater Morphs are drab and dark, although the pattern is reversed in dark tannic lakes. Morphs shift from benthic to pelagic feeding at a length of 400–490 mm. Phenotypic differences in locomotion, buoyancy and lipid metabolism evolved into different mechanisms for buoyancy regulation, with lean Morphs relying on hydrodynamic lift and siscowet Morphs relying on hydrostatic lift. We suggest that the Salvelinus genus, rather than the species S. alpinus, is a diverse genus that should be the subject of comparative studies of processes causing divergence and adaptation among member species that may lead to a more complete evolutionary conceptual model.
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life history differences between fat and lean Morphs of lake charr salvelinus namaycush in great slave lake northwest territories canada
Hydrobiologia, 2016Co-Authors: Michael J Hansen, Louise Chavarie, Nancy A Nate, Andrew M Muir, Mara S Zimmerman, Charles C KruegerAbstract:Life history characteristics (size, age, plumpness, buoyancy, survival, growth, and maturity) were compared between fat and lean Morphs of lake charr Salvelinus namaycush in Great Slave Lake, Canada, to determine if differences may reflect effects of resource polymorphism. Lake charr were sampled using graded-mesh gill nets set in three depth strata. Of 236 lake charr captured, 122 were a fat morph and 114 were a lean morph. Males and females did not differ from each other in any attributes for either fat or lean Morphs. The fat morph averaged 15 mm longer, 481 g heavier, and 4.7 years older than the lean morph. The fat morph averaged 26% heavier and 48% more buoyant at length than the lean morph. Survival of the fat morph was 1.7% higher than that of the lean morph. The fat morph grew at a slower annual rate to a shorter asymptotic length than the lean morph. Fat and lean Morphs matured at similar lengths and ages. We concluded that the connection between resource polymorphism and life histories in lean versus fat lake charr suggests that morph-specific restoration objectives may be needed in lakes where lake charr diversity is considered to be a restoration goal.
Charlyn G. Partridge - One of the best experts on this subject based on the ideXlab platform.
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Identification and characterization of Gypsophila paniculata color Morphs in Sleeping Bear Dunes National Lakeshore, MI, USA.
PeerJ, 2019Co-Authors: Marisa L. Yang, Emma K. Rice, Hailee B. Leimbach-maus, Charlyn G. PartridgeAbstract:Background: Gypsophila paniculata (baby's breath) is an invasive species found throughout much of the northwest United States and western Canada. Recently, plants exhibiting a different color morphology were identified within the coastal dunes along eastern Lake Michigan. The common baby's breath (G. paniculata) typically produces stems that are purple in color (purple morph), while the atypical morph has stems that are green-yellow (green-yellow morph). The purpose of this study was to characterize these newly identified Morphs and determine if they are genetically distinct species from the common baby's breath in order to assess whether alternative management strategies should be employed to control these populations. Methods: We sequenced two chloroplast regions, ribulose-bisphosphate carboxylase gene (rbcL), and maturase K (matK), and one nuclear region, internal transcribed spacer 2 (ITS2), from the purple Morphs and green-yellow Morphs collected from Sleeping Bear Dunes National Lakeshore, MI, USA (SBDNL). Sequences were aligned to reference sequences from other Gypsophila species obtained from the Barcode of Life Database and GenBank databases. We also collected seeds from wild purple morph and wild green-yellow morph plants in SBDNL. We grew the seeds in a common garden setting and characterized the proportion of green-yellow individuals produced from the two color Morphs after 5-months of growth. Results: Phylogenetic analyses based upon rbcL, matK, and ITS2 regions suggest that the two color Morphs are not distinct species and they both belong to G. paniculata. Seeds collected from wild green-yellow Morphs produced a significantly higher proportion of green-yellow individuals compared to the number produced by seeds collected from wild purple Morphs. However, seeds collected from both color Morphs produced more purple Morphs than green-yellow Morphs. Discussion: Based upon these results, we propose that the two color Morphs are variants of G. paniculata. Given the significant difference in the number of green-yellow Morphs produced from the seeds of each morph type, we also suggest that this color difference has some genetic basis. We propose that current management continue to treat the two color Morphs in a similar manner in terms of removal to prevent the further spread of this species.
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Identification and characterization of Gypsophila paniculata color Morphs in Sleeping Bear Dunes National Lakeshore, MI, USA.
bioRxiv, 2017Co-Authors: Marisa L. Yang, Emma K. Rice, Hailee Leimbach-mas, Charlyn G. PartridgeAbstract:Gypsophila paniculata (babys breath) is an invasive species found throughout much of the northwest United States and western Canada. Two distinct color Morphs of babys breath were identified in areas within the coastal dunes along eastern Lake Michigan. The more common morph produces stems that are purple in color (purple morph), while the atypical morph has stems that are green-yellow (green-yellow morph). The purpose of this study was to characterize these Morphs and determine if they are genetically distinct species in order to assess whether alternative management strategies should be employed to control these populations. We sequenced two chloroplast regions, RbcL and MatK, and one nuclear region, ITS2, from the purple Morphs and green-yellow Morphs collected from Sleeping Bear Dunes National Lakeshore, MI, USA. Sequences were aligned with reference G. paniculata and G. elegans sequences obtained from GenBank and the Barcode of Life (BOLD) databases. Phylogenetic analyses suggest that the two color Morphs belong to G. paniculata and do not appear to be distinct genetic strains. We propose that current management practices continue to treat the two color Morphs in a similar manner in terms of removal to prevent the further spread of this species.
Jukka Jokela - One of the best experts on this subject based on the ideXlab platform.
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water temperature not fish morph determines parasite infections of sympatric icelandic threespine sticklebacks gasterosteus aculeatus
Ecology and Evolution, 2013Co-Authors: Anssi Karvonen, Bjarni K Kristjansson, Skuli Skulason, Maiju Lanki, Christian Rellstab, Jukka JokelaAbstract:Parasite communities of fishes are known to respond directly to the abiotic environment of the host, for example, to water quality and water temperature. Biotic factors are also important as they affect the exposure profile through heterogeneities in parasite distribution in the environment. Parasites in a particular environment may pose a strong selection on fish. For example, ecological differences in selection by parasites have been hypothesized to facilitate evolutionary differentiation of freshwater fish Morphs specializing on different food types. However, as parasites may also respond directly to abiotic environment the parasite risk does not depend only on biotic features of the host environment. It is possible that different Morphs experience specific selection gradients by parasites but it is not clear how consistent the selection is when abiotic factors change. We examined parasite pressure in sympatric Morphs of threespine stickleback (Gasterosteus aculeatus) across a temperature gradient in two large Icelandic lakes, Myvatn and Thingvallavatn. Habitat-specific temperature gradients in these lakes are opposite. Myvatn lava rock morph lives in a warm environment, while the mud morph lives in the cold. In Thingvallavatn, the lava rock morph lives in a cold environment and the mud morph in a warm habitat. We found more parasites in fish living in higher temperature in both lakes, independent of the fish morph, and this pattern was similar for the two dominating parasite taxa, trematodes and cestodes. However, at the same time, we also found higher parasite abundance in a third morph living in deep cold–water habitat in Thingvallavatn compared to the cold-water lava morph, indicating strong effect of habitat-specific biotic factors. Our results suggest complex interactions between water temperature and biotic factors in determining the parasite community structure, a pattern that may have implications for differentiation of stickleback Morphs.
