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Dustin J. Marshall - One of the best experts on this subject based on the ideXlab platform.
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the biogeography of Marine Invertebrate life histories
Annual Review of Ecology Evolution and Systematics, 2012Co-Authors: Dustin J. Marshall, Maria Byrne, Patrick J Krug, Elena K Kupriyanova, Richard B EmletAbstract:Biologists have long sought to identify and explain patterns in the diverse array of Marine life histories. The most famous speculation about such patterns is Gunnar Thorson’s suggestion that species producing planktonic larvae are rarer at higher latitudes (Thorson’s rule). Although some elements of Thorson’s rule have proven incorrect, other elements remain untested. With a wealth of new life-history data, statistical approaches, and remote-sensing technology, new insights into Marine reproduction can be generated. We gathered life-history data for more than 1,000 Marine Invertebrates and examined patterns in the prevalence of different life histories. Systematic patterns in Marine life histories exist at a range of scales, some of which support Thorson, whereas others suggest previously unrecognized relationships between the Marine environment and the life histories of Marine Invertebrates. Overall, Marine life histories covary strongly with temperature and local ocean productivity, and different regions should be managed accordingly.
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genetic diversity increases population productivity in a sessile Marine Invertebrate
Ecology, 2012Co-Authors: David J Aguirre, Dustin J. MarshallAbstract:Reductions in genetic diversity can have widespread ecological consequences: populations with higher genetic diversity are more stable, productive and resistant to disturbance or disease than populations with lower genetic diversity. These ecological effects of genetic diversity differ from the more familiar evolutionary consequences of depleting genetic diversity, because ecological effects manifest within a single generation. If common, genetic diversity effects have the potential to change the way we view and manage populations, but our understanding of these effects is far from complete, and the role of genetic diversity in sexually reproducing animals remains unclear. Here, we examined the effects of genetic diversity in a sexually reproducing Marine Invertebrate in the field. We manipulated the genetic diversity of experimental populations and then measured individual survival, growth, and fecundity, as well as the size of offspring produced by individuals in high and low genetic diversity populations. Overall, we found greater genetic diversity increased performance across all metrics, and that complementarity effects drove the increased productivity of our high-diversity populations. Our results show that differences in genetic diversity among populations can have pervasive effects on population productivity within remarkably short periods of time.
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Propagule size effects across multiple life‐history stages in a Marine Invertebrate
Functional Ecology, 2009Co-Authors: Marc Rius, Xavier Turon, Gustavo Muniz Dias, Dustin J. MarshallAbstract:Summary: 1. Mothers must balance the fecundity costs of increasing propagule size with the fitness benefits of increased propagule performance, and the propagule size-performance relationship is crucial for determining this trade-off. 2. While many studies have examined the propagule size-performance relationship in individual life-history stages, very few have examined the relationship between propagule size and performance across multiple life-history stages despite the ubiquity of complex life cycles. 3. We examined the consistency of the propagule size-performance relationship across several life-history stages in the Marine Invertebrate Microcosmus squamiger (Ascidiacea). 4. Propagule size had effects in some life-history stages and not others: larger propagules hatched sooner as larvae and grew more as juveniles in the field. On the other hand, propagule size had no effect on cell cleavage rates, larval swimming time or post-metamorphic survival in the field. 5. The effects of propagule size on juvenile size were persistent - juveniles that came from larger propagules were still larger than juveniles that came from smaller propagules after 11 weeks in the field. 6. We found no evidence of conflicting selection pressures on propagule size among life-history stages. Rather, in this species at least, the selection on propagule size at both the larval and juvenile stage appeared to favour the production of larger propagules. Nevertheless, the slope of the relationship between propagule size and performance was highly variable among life-history stages. 7. The effects of propagule size across multiple life-history stages are determined by the strength of selection pressures, which can be highly variable in organisms with complex life-cycles. © 2009 The Authors. Journal compilation
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gamete plasticity in a broadcast spawning Marine Invertebrate
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: Angela J Crean, Dustin J. MarshallAbstract:Sperm competition has classically been thought to maintain anisogamy (large eggs and smaller sperm) because males are thought to maximize their chance of winning fertilizations by trading sperm size for number. More recently it has been recognized that sperm quality (e.g., size, velocity) can also influence sperm competition, although studies have yielded conflicting results. Because sex evolved in the sea, debate has continued over the role of sperm competition and sperm environment in determining both sperm and egg size in externally fertilizing broadcast spawners. Remarkably, however, there have been no direct tests of whether broadcast spawners change the traits of their gametes depending on the likelihood of sperm competition. We manipulated the density (and thus, sperm environment) of a broadcast spawning ascidian (Styela plicata) in the field and then determined whether the phenotype of eggs and sperm changed. We found that sperm from adults kept at high density were larger and more motile than sperm from low-density adults. In vitro fertilizations revealed that sperm from high-density adults also lived longer and induced less polyspermy. Adult density also affected egg traits: eggs from high-density adults were smaller targets for sperm overall but produced larger ovicells than eggs from low-density adults. This suggests that broadcast spawning mothers balance (potentially conflicting) pre- and postzygotic selection pressures on egg size. Overall, our results suggest that sperm competition does not represent a strong force maintaining anisogamy in broadcast spawners. Instead, sperm limitation seems to select for large eggs and smaller, more numerous sperm.
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GENETIC MECHANISMS OF POLLUTION RESISTANCE IN A Marine Invertebrate
Ecological applications : a publication of the Ecological Society of America, 2007Co-Authors: Bronwyn C. Galletly, Mark W. Blows, Dustin J. MarshallAbstract:Pollution is a common stress in the Marine environment and one of today's most powerful agents of selection, yet we have little understanding of how anthropogenic toxicants influence mechanisms of adaptation in Marine populations. Due to their life history strategies, Marine Invertebrates are unable to avoid stress and must adapt to variable environments. We examined the genetic basis of pollution resistance across multiple environments using the Marine Invertebrate, Styela plicata. Gametes were crossed in a quantitative genetic breeding design to enable partitioning of additive genetic variance across a concentration gradient of a common Marine pollutant, copper. Hatching success was scored as a measure of stress resistance in copper concentrations of 0, 75, 150, and 350 μg/L. There was a significant genotype × environment interaction in hatching success across copper concentrations. Further analysis using factor analytic modeling confirmed a significant dimension of across-environment genetic variation ...
Kyall R Zenger - One of the best experts on this subject based on the ideXlab platform.
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swept away ocean currents and seascape features influence genetic structure across the 18 000 km indo pacific distribution of a Marine Invertebrate the black lip pearl oyster pinctada margaritifera
BMC Genomics, 2017Co-Authors: Monal M Lal, Paul C Southgate, Dean R Jerry, Cyprien Bosserelle, Kyall R ZengerAbstract:Genetic structure in many widely-distributed broadcast spawning Marine Invertebrates remains poorly understood, posing substantial challenges for their fishery management, conservation and aquaculture. Under the Core-Periphery Hypothesis (CPH), genetic diversity is expected to be highest at the centre of a species’ distribution, progressively decreasing with increased differentiation towards outer range limits, as populations become increasingly isolated, fragmented and locally adapted. The unique life history characteristics of many Marine Invertebrates such as high dispersal rates, stochastic survival and variable recruitment are also likely to influence how populations are organised. To examine the microevolutionary forces influencing population structure, connectivity and adaptive variation in a highly-dispersive bivalve, populations of the black-lip pearl oyster Pinctada margaritifera were examined across its ~18,000 km Indo-Pacific distribution. Analyses utilising 9,624 genome-wide SNPs and 580 oysters, discovered differing patterns of significant and substantial broad-scale genetic structure between the Indian and Pacific Ocean basins. Indian Ocean populations were markedly divergent (F st = 0.2534–0.4177, p < 0.001), compared to Pacific Ocean oysters, where basin-wide gene flow was much higher (F st = 0.0007–0.1090, p < 0.001). Partitioning of genetic diversity (hierarchical AMOVA) attributed 18.1% of variance between ocean basins, whereas greater proportions were resolved within samples and populations (45.8% and 35.7% respectively). Visualisation of population structure at selectively neutral loci resolved three and five discrete genetic clusters for the Indian and Pacific Oceans respectively. Evaluation of genetic structure at adaptive loci for Pacific populations (89 SNPs under directional selection; F st = 0.1012–0.4371, FDR = 0.05), revealed five clusters identical to those detected at neutral SNPs, suggesting environmental heterogeneity within the Pacific. Patterns of structure and connectivity were supported by Mantel tests of isolation by distance (IBD) and independent hydrodynamic particle dispersal simulations. It is evident that genetic structure and connectivity across the natural range of P. margaritifera is highly complex, and produced by the interaction of ocean currents, IBD and seascape features at a broad scale, together with habitat geomorphology and local adaptation at regional levels. Overall population organisation is far more elaborate than generalised CPH predictions, however valuable insights for regional fishery management, and a greater understanding of range-wide genetic structure in a highly-dispersive Marine Invertebrate have been gained.
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fishing for divergence in a sea of connectivity the utility of ddradseq genotyping in a Marine Invertebrate the black lip pearl oyster pinctada margaritifera
Marine Genomics, 2016Co-Authors: Monal M Lal, Paul C Southgate, Dean R Jerry, Kyall R ZengerAbstract:Population genomic investigations on highly dispersive Marine organisms typically require thousands of genome-wide SNP loci to resolve fine-scale population structure and detect signatures of selection. This information is important for species conservation efforts and stock management in both wild and captive populations, as well as genome mapping and genome wide association studies. Double digest Restriction site-Associated DNA Sequencing (ddRADseq) is a recent tool for delivering genome wide SNPs for non-model organisms. However, its application to Marine Invertebrate taxa has been limited, particularly given the complex and highly repetitive nature of many of these organisms' genomes. This study develops and evaluates an optimised ddRADseq technique together with associated analyses for generating genome-wide SNP data, and performs population genomic analyses to inform aquaculture and fishery management of a Marine bivalve, the black-lip pearl oyster Pinctada margaritifera. A total of 5243 high-quality genome-wide SNP markers were detected, and used to assess population structure, genome diversity, detect Fst outliers and perform association testing in 156 individuals belonging to three wild and one hatchery produced populations from the Fiji Islands. Shallow but significant population structure was revealed among all wild populations (average pairwise Fst=0.046) when visualised with DAPC and an individual network analysis (NetView P), with clear evidence of a genetic bottleneck in the hatchery population (NeLD=6.1), compared to wild populations (NeLD>192.5). Fst outlier detection revealed 42-62 highly differentiated SNPs (p<0.02), while case-control association discovered up to 152 SNPs (p<0.001). Both analyses were able to successfully differentiate individuals between the orange and black tissue colour morphotypes characteristic of this species. BLAST searches revealed that five of these SNPs were associated with a melanin biosynthesis pathway, demonstrating their biological relevance. This study has produced highly informative SNP and population genomic data in P. margaritifera, and using the same approach promises to be of substantial value to a range of other non-model, broadcast-spawning or Marine Invertebrate taxa.
Paul C Southgate - One of the best experts on this subject based on the ideXlab platform.
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swept away ocean currents and seascape features influence genetic structure across the 18 000 km indo pacific distribution of a Marine Invertebrate the black lip pearl oyster pinctada margaritifera
BMC Genomics, 2017Co-Authors: Monal M Lal, Paul C Southgate, Dean R Jerry, Cyprien Bosserelle, Kyall R ZengerAbstract:Genetic structure in many widely-distributed broadcast spawning Marine Invertebrates remains poorly understood, posing substantial challenges for their fishery management, conservation and aquaculture. Under the Core-Periphery Hypothesis (CPH), genetic diversity is expected to be highest at the centre of a species’ distribution, progressively decreasing with increased differentiation towards outer range limits, as populations become increasingly isolated, fragmented and locally adapted. The unique life history characteristics of many Marine Invertebrates such as high dispersal rates, stochastic survival and variable recruitment are also likely to influence how populations are organised. To examine the microevolutionary forces influencing population structure, connectivity and adaptive variation in a highly-dispersive bivalve, populations of the black-lip pearl oyster Pinctada margaritifera were examined across its ~18,000 km Indo-Pacific distribution. Analyses utilising 9,624 genome-wide SNPs and 580 oysters, discovered differing patterns of significant and substantial broad-scale genetic structure between the Indian and Pacific Ocean basins. Indian Ocean populations were markedly divergent (F st = 0.2534–0.4177, p < 0.001), compared to Pacific Ocean oysters, where basin-wide gene flow was much higher (F st = 0.0007–0.1090, p < 0.001). Partitioning of genetic diversity (hierarchical AMOVA) attributed 18.1% of variance between ocean basins, whereas greater proportions were resolved within samples and populations (45.8% and 35.7% respectively). Visualisation of population structure at selectively neutral loci resolved three and five discrete genetic clusters for the Indian and Pacific Oceans respectively. Evaluation of genetic structure at adaptive loci for Pacific populations (89 SNPs under directional selection; F st = 0.1012–0.4371, FDR = 0.05), revealed five clusters identical to those detected at neutral SNPs, suggesting environmental heterogeneity within the Pacific. Patterns of structure and connectivity were supported by Mantel tests of isolation by distance (IBD) and independent hydrodynamic particle dispersal simulations. It is evident that genetic structure and connectivity across the natural range of P. margaritifera is highly complex, and produced by the interaction of ocean currents, IBD and seascape features at a broad scale, together with habitat geomorphology and local adaptation at regional levels. Overall population organisation is far more elaborate than generalised CPH predictions, however valuable insights for regional fishery management, and a greater understanding of range-wide genetic structure in a highly-dispersive Marine Invertebrate have been gained.
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fishing for divergence in a sea of connectivity the utility of ddradseq genotyping in a Marine Invertebrate the black lip pearl oyster pinctada margaritifera
Marine Genomics, 2016Co-Authors: Monal M Lal, Paul C Southgate, Dean R Jerry, Kyall R ZengerAbstract:Population genomic investigations on highly dispersive Marine organisms typically require thousands of genome-wide SNP loci to resolve fine-scale population structure and detect signatures of selection. This information is important for species conservation efforts and stock management in both wild and captive populations, as well as genome mapping and genome wide association studies. Double digest Restriction site-Associated DNA Sequencing (ddRADseq) is a recent tool for delivering genome wide SNPs for non-model organisms. However, its application to Marine Invertebrate taxa has been limited, particularly given the complex and highly repetitive nature of many of these organisms' genomes. This study develops and evaluates an optimised ddRADseq technique together with associated analyses for generating genome-wide SNP data, and performs population genomic analyses to inform aquaculture and fishery management of a Marine bivalve, the black-lip pearl oyster Pinctada margaritifera. A total of 5243 high-quality genome-wide SNP markers were detected, and used to assess population structure, genome diversity, detect Fst outliers and perform association testing in 156 individuals belonging to three wild and one hatchery produced populations from the Fiji Islands. Shallow but significant population structure was revealed among all wild populations (average pairwise Fst=0.046) when visualised with DAPC and an individual network analysis (NetView P), with clear evidence of a genetic bottleneck in the hatchery population (NeLD=6.1), compared to wild populations (NeLD>192.5). Fst outlier detection revealed 42-62 highly differentiated SNPs (p<0.02), while case-control association discovered up to 152 SNPs (p<0.001). Both analyses were able to successfully differentiate individuals between the orange and black tissue colour morphotypes characteristic of this species. BLAST searches revealed that five of these SNPs were associated with a melanin biosynthesis pathway, demonstrating their biological relevance. This study has produced highly informative SNP and population genomic data in P. margaritifera, and using the same approach promises to be of substantial value to a range of other non-model, broadcast-spawning or Marine Invertebrate taxa.
Lani U. Gleason - One of the best experts on this subject based on the ideXlab platform.
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Applications and Future Directions for Population Transcriptomics in Marine Invertebrates
Current Molecular Biology Reports, 2019Co-Authors: Lani U. GleasonAbstract:Purpose of Review RNA-sequencing has provided a new way to study transcriptomic population differences of non-model organisms such as Marine Invertebrates. Importantly, population transcriptomics can provide insight regarding the genetic mechanisms that allow some populations to tolerate various environmental stressors in this era of climate change. Such studies can help us predict future population dynamics and species survival for Marine Invertebrates of ecological and economic value. Here, I review practical considerations for Marine Invertebrate researchers using RNA-sequencing, recent applications of population transcriptomics in Marine Invertebrates, current limitations of this approach, and future areas of study. Recent Findings Recent Marine Invertebrate studies have examined population-specific responses to abiotic stressors including temperature, salinity, pH, and water quality. Populations tolerant of environmental stressors generally show high constitutive gene expression before stress exposure and a muted overall transcriptional response following stress exposure. Evidence for molecular signatures of selection on several genes including ATP synthase and aquaporins has been identified in Marine Invertebrate populations exposed to broad temperature regimes. At present, the genetic mechanisms underlying individual variation within a population and the transcriptome response to multiple environmental stressors remain poorly understood. Summary Complete assessment of Marine Invertebrate population responses to climate change will require pairing RNA-sequencing approaches with complementary phenotype studies. Improvements in transcriptome annotation and future work investigating gene expression regulation will lead to an increased understanding of the genes responsible for population-level tolerance to environmental stressors.
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Applications and Future Directions for Population Transcriptomics in Marine Invertebrates
Current Molecular Biology Reports, 2019Co-Authors: Lani U. GleasonAbstract:RNA-sequencing has provided a new way to study transcriptomic population differences of non-model organisms such as Marine Invertebrates. Importantly, population transcriptomics can provide insight regarding the genetic mechanisms that allow some populations to tolerate various environmental stressors in this era of climate change. Such studies can help us predict future population dynamics and species survival for Marine Invertebrates of ecological and economic value. Here, I review practical considerations for Marine Invertebrate researchers using RNA-sequencing, recent applications of population transcriptomics in Marine Invertebrates, current limitations of this approach, and future areas of study. Recent Marine Invertebrate studies have examined population-specific responses to abiotic stressors including temperature, salinity, pH, and water quality. Populations tolerant of environmental stressors generally show high constitutive gene expression before stress exposure and a muted overall transcriptional response following stress exposure. Evidence for molecular signatures of selection on several genes including ATP synthase and aquaporins has been identified in Marine Invertebrate populations exposed to broad temperature regimes. At present, the genetic mechanisms underlying individual variation within a population and the transcriptome response to multiple environmental stressors remain poorly understood. Complete assessment of Marine Invertebrate population responses to climate change will require pairing RNA-sequencing approaches with complementary phenotype studies. Improvements in transcriptome annotation and future work investigating gene expression regulation will lead to an increased understanding of the genes responsible for population-level tolerance to environmental stressors.
Monal M Lal - One of the best experts on this subject based on the ideXlab platform.
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swept away ocean currents and seascape features influence genetic structure across the 18 000 km indo pacific distribution of a Marine Invertebrate the black lip pearl oyster pinctada margaritifera
BMC Genomics, 2017Co-Authors: Monal M Lal, Paul C Southgate, Dean R Jerry, Cyprien Bosserelle, Kyall R ZengerAbstract:Genetic structure in many widely-distributed broadcast spawning Marine Invertebrates remains poorly understood, posing substantial challenges for their fishery management, conservation and aquaculture. Under the Core-Periphery Hypothesis (CPH), genetic diversity is expected to be highest at the centre of a species’ distribution, progressively decreasing with increased differentiation towards outer range limits, as populations become increasingly isolated, fragmented and locally adapted. The unique life history characteristics of many Marine Invertebrates such as high dispersal rates, stochastic survival and variable recruitment are also likely to influence how populations are organised. To examine the microevolutionary forces influencing population structure, connectivity and adaptive variation in a highly-dispersive bivalve, populations of the black-lip pearl oyster Pinctada margaritifera were examined across its ~18,000 km Indo-Pacific distribution. Analyses utilising 9,624 genome-wide SNPs and 580 oysters, discovered differing patterns of significant and substantial broad-scale genetic structure between the Indian and Pacific Ocean basins. Indian Ocean populations were markedly divergent (F st = 0.2534–0.4177, p < 0.001), compared to Pacific Ocean oysters, where basin-wide gene flow was much higher (F st = 0.0007–0.1090, p < 0.001). Partitioning of genetic diversity (hierarchical AMOVA) attributed 18.1% of variance between ocean basins, whereas greater proportions were resolved within samples and populations (45.8% and 35.7% respectively). Visualisation of population structure at selectively neutral loci resolved three and five discrete genetic clusters for the Indian and Pacific Oceans respectively. Evaluation of genetic structure at adaptive loci for Pacific populations (89 SNPs under directional selection; F st = 0.1012–0.4371, FDR = 0.05), revealed five clusters identical to those detected at neutral SNPs, suggesting environmental heterogeneity within the Pacific. Patterns of structure and connectivity were supported by Mantel tests of isolation by distance (IBD) and independent hydrodynamic particle dispersal simulations. It is evident that genetic structure and connectivity across the natural range of P. margaritifera is highly complex, and produced by the interaction of ocean currents, IBD and seascape features at a broad scale, together with habitat geomorphology and local adaptation at regional levels. Overall population organisation is far more elaborate than generalised CPH predictions, however valuable insights for regional fishery management, and a greater understanding of range-wide genetic structure in a highly-dispersive Marine Invertebrate have been gained.
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fishing for divergence in a sea of connectivity the utility of ddradseq genotyping in a Marine Invertebrate the black lip pearl oyster pinctada margaritifera
Marine Genomics, 2016Co-Authors: Monal M Lal, Paul C Southgate, Dean R Jerry, Kyall R ZengerAbstract:Population genomic investigations on highly dispersive Marine organisms typically require thousands of genome-wide SNP loci to resolve fine-scale population structure and detect signatures of selection. This information is important for species conservation efforts and stock management in both wild and captive populations, as well as genome mapping and genome wide association studies. Double digest Restriction site-Associated DNA Sequencing (ddRADseq) is a recent tool for delivering genome wide SNPs for non-model organisms. However, its application to Marine Invertebrate taxa has been limited, particularly given the complex and highly repetitive nature of many of these organisms' genomes. This study develops and evaluates an optimised ddRADseq technique together with associated analyses for generating genome-wide SNP data, and performs population genomic analyses to inform aquaculture and fishery management of a Marine bivalve, the black-lip pearl oyster Pinctada margaritifera. A total of 5243 high-quality genome-wide SNP markers were detected, and used to assess population structure, genome diversity, detect Fst outliers and perform association testing in 156 individuals belonging to three wild and one hatchery produced populations from the Fiji Islands. Shallow but significant population structure was revealed among all wild populations (average pairwise Fst=0.046) when visualised with DAPC and an individual network analysis (NetView P), with clear evidence of a genetic bottleneck in the hatchery population (NeLD=6.1), compared to wild populations (NeLD>192.5). Fst outlier detection revealed 42-62 highly differentiated SNPs (p<0.02), while case-control association discovered up to 152 SNPs (p<0.001). Both analyses were able to successfully differentiate individuals between the orange and black tissue colour morphotypes characteristic of this species. BLAST searches revealed that five of these SNPs were associated with a melanin biosynthesis pathway, demonstrating their biological relevance. This study has produced highly informative SNP and population genomic data in P. margaritifera, and using the same approach promises to be of substantial value to a range of other non-model, broadcast-spawning or Marine Invertebrate taxa.
