scholarly journals Lack of spatial genetic variation in the edible crab (Cancer pagurus) in the Kattegat–Skagerrak area

2009 ◽  
Vol 66 (3) ◽  
pp. 462-469 ◽  
Author(s):  
Anette Ungfors ◽  
Niall J. McKeown ◽  
Paul W. Shaw ◽  
Carl André
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Larval Dispersal ◽  
Power Analysis ◽  
Norwegian Sea ◽  
Cancer Pagurus ◽  
Genotype Frequencies ◽  
Contemporary Gene Flow ◽  
Large Populations ◽  
Spatial Genetic Variation

Abstract Ungfors, A., McKeown, N. J., Shaw, P. W., and André, C. 2009. Lack of spatial genetic variation in the edible crab (Cancer pagurus) in the Kattegat–Skagerrak area. – ICES Journal of Marine Science, 66: 462–469. The stock structure of the edible crab (Cancer pagurus L.) in the Kattegat and Skagerrak was investigated using eight microsatellite DNA loci. Replicate samples, collected 4–6 years apart, were derived from the Kattegat (Grove Bank, 57°N) and the Skagerrak (Lunneviken, 59°N), plus a geographical outgroup sample from the Norwegian Sea (Midsund, 62°N). Genetic differentiation among samples, estimated as global FST = 0.002, was significant (p = 0.03) when the statistical test was based on allele frequencies, but not when based on genotype frequencies. Moreover, all single- and multilocus pairwise tests between samples were non-significant. An analysis of molecular variance, AMOVA, did not reveal significant differentiation between spatial (Kattegat vs. Skagerrak) or temporal (2001/2002 vs. 2006/2007) groups of samples. Power analysis suggested that the loci and sample sizes employed conferred a power of >90% of detecting even low (true FST = 0.002) levels of population structure. Low spatial and temporal genetic structure might be explained by either or both of (i) high levels of contemporary gene flow in the area attributable to adult migration or larval dispersal or both factors taken together, and (ii) patterns of historical gene flow persisting among recently founded large populations.

scholarly journals Seascape genomics reveals population isolation in the reef-building honeycomb worm, Sabellaria alveolata (L.)

2019 ◽  
Author(s):  
Anna P Muir ◽  
Stanislas F. Dubois ◽  
Rebecca E. Ross ◽  
Louise B. Firth ◽  
Antony M. Knights ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
North Atlantic ◽  
Larval Dispersal ◽  
Balancing Selection ◽  
Isolated Population ◽  
The North ◽  
Outlier Loci ◽  
Dispersal Potential ◽  
The North Atlantic

Abstract Background Under the threat of climate change populations can disperse, acclimatise or evolve in order to avoid fitness loss. In light of this, it is important to understand neutral gene flow patterns as a measure of dispersal potential, but also adaptive genetic variation as a measure of evolutionary potential. In order to assess genetic variation and how this relates to environment in the honeycomb worm (Sabellaria alveolata (L.)), a reef-building polychaete that supports high biodiversity, we carried out RAD sequencing using individuals from along its complete latitudinal range. Patterns of neutral population genetic structure were compared to larval dispersal as predicted by ocean circulation modelling, and outlier analyses and genotype-environment associations tests were used to attempt to identify loci under selection in relation to local temperature data. Results We genotyped 482 filtered SNPs, from 68 individuals across nine sites, 27 of which were identified as outliers using BAYESCAN and ARLEQUIN. All outlier loci were potentially under balancing selection, despite previous evidence of local adaptation in the system. Limited gene flow was observed among reef-sites (FST = 0.28 ± 0.10), in line with the low dispersal potential identified by the larval dispersal models. The North Atlantic reef emerged as an isolated population and this was linked to high local larval retention and the effect of the North Atlantic Current on dispersal. Conclusions As an isolated population, with limited potential for natural genetic or demographic augmentation from other reefs, the North Atlantic site warrants conservation attention in order to preserve not only this species, but above all the crucial functional ecological roles that are associated with their bioconstructions. Our study highlights the utility of using seascape genomics to identify populations of conservation concern.

scholarly journals Seascape genomics reveals population isolation in the reef-building honeycomb worm, Sabellaria alveolata (L.)

2020 ◽  
Author(s):  
Anna P Muir ◽  
Stanislas F. Dubois ◽  
Rebecca E. Ross ◽  
Louise B. Firth ◽  
Antony M. Knights ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Larval Dispersal ◽  
Balancing Selection ◽  
The North ◽  
Outlier Loci ◽  
Dispersal Potential ◽  
The North Atlantic

Abstract Background: Under the threat of climate change populations can disperse, acclimatise or evolve in order to avoid fitness loss. In light of this, it is important to understand neutral gene flow patterns as a measure of dispersal potential, but also adaptive genetic variation as a measure of evolutionary potential. In order to assess genetic variation and how this relates to environment in the honeycomb worm (Sabellaria alveolata (L.)), a reef-building polychaete that supports high biodiversity, we carried out RAD sequencing using individuals from along its complete latitudinal range. Patterns of neutral population genetic structure were compared to larval dispersal as predicted by ocean circulation modelling, and outlier analyses and genotype-environment association tests were used to attempt to identify loci under selection in relation to local temperature data. Results: We genotyped 482 filtered SNPs, from 68 individuals across nine sites, 27 of which were identified as outliers using BAYESCAN and ARLEQUIN. All outlier loci were potentially under balancing selection, despite previous evidence of local adaptation in the system. Limited gene flow was observed among reef-sites (FST= 0.28 ± 0.10), in line with the low dispersal potential identified by the larval dispersal models. The North Atlantic reef emerged as a distinct population and this was linked to high local larval retention and the effect of the North Atlantic Current on dispersal. Conclusions: As an isolated population, with limited potential for natural genetic or demographic augmentation from other reefs, the North Atlantic site warrants conservation attention in order to preserve not only this species, but above all the crucial functional ecological roles that are associated with their bioconstructions. Our study highlights the utility of using seascape genomics to identify populations of conservation concern.

Changes in allele and genotype frequency

2019 ◽  
pp. 49-68
Author(s):  
Glenn-Peter Sætre ◽  
Mark Ravinet
Keyword(s):  
Population Genetics ◽  
Genetic Variation ◽  
Gene Flow ◽  
Goodness Of Fit ◽  
Random Mating ◽  
Evolutionary Forces ◽  
Goodness Of Fit Tests ◽  
Genotype Frequencies ◽  
Successive Generations ◽  
The Relationship

Evolution is the change in heritable traits of populations over successive generations. At the molecular level this translates into changes in their genetic composition. A general theoretical investigation of how different demographic and evolutionary processes affect genetic variation within and between populations provides us with tools to reconstruct evolutionary history. This is the fundamental purpose of population genetics. This chapter investigates the relationship between allele and genotype frequencies in a hypothetical population that is not subjected to any evolutionary forces—i.e. the Hardy–Weinberg model. Then, one by one, demographic and evolutionary factors such as non-random mating, genetic drift, selection, mutation, and gene flow are introduced to investigate in what ways they affect allele and/or genotype frequencies. The chapter further introduces F-statistics and goodness of fit tests to investigate statistical deviations from expectations.

Evidence of genetic subdivision among populations of blacklip abalone (Haliotis rubra Leach) in Tasmania

2007 ◽  
Vol 58 (8) ◽  
pp. 733 ◽  
Author(s):  
Nepelle Temby ◽  
Karen Miller ◽  
Craig Mundy
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Microsatellite Dna ◽  
Larval Dispersal ◽  
Field Experiments ◽  
Field Studies ◽  
Genetic Studies ◽  
Small Scales ◽  
Commercial Species ◽  
Haliotis Rubra

The scale over which populations exchange individuals (migration) is central to ecology, and important for understanding recruitment and connectivity in commercial species. Field studies indicate that blacklip abalone (Haliotis rubra) have localised larval dispersal. However, genetic studies show differentiation only at large scales, suggesting dispersal over more than 100 km. Most genetic studies, however, have failed to test for subdivision at scales equivalent to field experiments. We used microsatellite DNA to investigate genetic structure at small scales (100 m to 10 km) in blacklip abalone in south-east Tasmania. We found significant subdivision (FST = 0.021; P < 0.05) among sites, and hierarchical FST analysis indicated 64% of genetic variation was at the smallest scale, supporting field studies that concluded larval dispersal is less than 100m. We also tested if genetic differentiation varied predictably with wave exposure, but found no evidence that differences between adjacent sites in exposed locations varied from differences between adjacent sites in sheltered populations (mean FST = 0.016 and 0.017 respectively). Our results show the usefulness of microsatellites for abalone, but also identify sampling scales as critical in understanding gene flow and dispersal of abalone larvae in an ecologically relevant framework. Importantly, our results indicate that H. rubra populations are self-recruiting, which will be important for the management of this commercial species.

Habitat differentiation between estuarine and inland Hibiscus tiliaceus L. (Malvaceae) as revealed by retrotransposon-based SSAP marker

2011 ◽  
Vol 59 (6) ◽  
pp. 515 ◽  
Author(s):  
Tian Tang ◽  
Lian He ◽  
Feng Peng ◽  
Suhua Shi
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Distance ◽  
Genetic Variance ◽  
Genetic Relationships ◽  
Principal Coordinate Analysis ◽  
Geographical Isolation ◽  
Tidal Zone ◽  
Ecological Scale ◽  
Habitat Differentiation

Hibiscus tiliaceus L. (Malvaceae) is a pantropical coastal tree that extends to the tidal zone. In this study, the retrotransposon sequence-specific amplified polymorphism (SSAP) technique was used in order to understand the genetic variation between four population pairs of H. tiliaceus from repeated estuarine and inland habitat contrasts in China. The estuarine populations were consistently more genetic variable compared with the inland ones, which may be attributed to extensive gene flow via water-drifted seeds and/or retrotransposon activation in stressful estuarine environments. An AMOVA revealed that 8.9% of the genetic variance could be explained by the habitat divergence within site, as compared with only 4.9% to geographical isolation between sites, which indicates significant habitat differentiation between the estuarine and inland populations. The estuarine populations were less differentiated (ΦST = 0.115) than the inland (ΦST = 0.152) implying frequent gene interchange in the former. Accordingly, the principal coordinate analysis of genetic distance between individuals revealed that genetic relationships are not fully consistent with the geographic association. These results suggest that despite substantial gene flow via sea-drifted seeds, habitat-related divergent selection could be one of the primary mechanisms that drive habitat differentiation in H. tiliaceus at a local ecological scale.

scholarly journals Genetic structure and historical and contemporary gene flow of Astyanaxmexicanus in the Gulf of Mexico slope: a microsatellite-based analysis

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10784
Author(s):  
Rodolfo Pérez-Rodríguez ◽  
Sarai Esquivel-Bobadilla ◽  
Adonaji Madeleine Orozco-Ruíz ◽  
José Luis Olivas-Hernández ◽  
Francisco Javier García-De León
Keyword(s):  
Gene Flow ◽  
Gulf Of Mexico ◽  
Microsatellite Loci ◽  
Evolutionary History ◽  
Population Analysis ◽  
Morphological Variability ◽  
High Capacity ◽  
Genetic Population ◽  
Contemporary Gene Flow ◽  
Taxonomic Uncertainty

Background Astyanax mexicanus from the river basins of the Gulf of Mexico slope are small freshwater fish that usually live in large groups in different freshwater environments. The group is considered successful due to its high capacity for dispersal and adaptation to different habitats, and the species present high morphological variability throughout their distribution in Mexico. This has produced the most extreme morphotype of the group; the hypogeous or troglobite, which has no eyes or coloration, and is probably the cause of taxonomic uncertainty in the recognition of species across the entire range. Most studies of A. mexicanus have mainly focused on cave individuals, as well as their adjacent surface locations, providing an incomplete evolutionary history, particularly in terms of factors related to dispersal and the potential corridors used, barriers to gene flow, and distribution of genetic variability. The aim of the present study is to determine the population structure and the degree and direction of genetic flow in this complex taxonomic group, incorporating geographic locations not previously included in analyses using microsatellite loci. Our aim is to contribute to the knowledge of the intricate evolutionary history of A. mexicanus throughout most of its range. Methods The present study included a set of several cave and surface locations of A. mexicanus, which have been widely sampled along the Gulf of Mexico slope, in a genetic population analysis using 10 microsatellite loci. Results Ten genetic populations or lineages were identified. In these populations, gene flow was recorded at two time periods. Historical gene flow, both inter and intra-basin, was observed among surface populations, from surface to cave populations, and among cave populations, whereas recording of contemporary gene flow was limited to intra-basin exchanges and observed among surface populations, surface to cave populations, and cave populations.

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