The Experts below are selected from a list of 35244 Experts worldwide ranked by ideXlab platform
Erkki Korpimäki - One of the best experts on this subject based on the ideXlab platform.
-
population fragmentation leads to Isolation by Distance but not genetic impoverishment in the philopatric lesser kestrel a comparison with the widespread and sympatric eurasian kestrel
Heredity, 2009Co-Authors: Miguel Alcaide, David Serrano, Toni Laaksonen, José Luis Tella, Juan J. Negro, C. Muller, Erkki KorpimäkiAbstract:Population fragmentation leads to Isolation by Distance but not genetic impoverishment in the philopatric Lesser Kestrel: a comparison with the widespread and sympatric Eurasian Kestrel
-
Population fragmentation leads to Isolation by Distance but not genetic impoverishment in the philopatric Lesser Kestrel: a comparison with the widespread and sympatric Eurasian Kestrel
Heredity, 2009Co-Authors: Miguel Alcaide, David Serrano, Toni Laaksonen, José Luis Tella, Juan J. Negro, C. Muller, A Gal, Erkki KorpimäkiAbstract:Population fragmentation is a widespread phenomenon usually associated with human activity. As a result of habitat transformation, the philopatric and steppe-specialist Lesser Kestrel Falco naumanni underwent a severe population decline during the last century that increased population fragmentation throughout its breeding range. In contrast, the ubiquitous Eurasian Kestrel Falco tinnunculus did not suffer such adverse effects, its breeding range still remaining rather continuous. Using microsatellites, we tested the effects of population fragmentation on large-scale spatial patterns of genetic differentiation and diversity by comparing these two sympatric and phylogenetically related species. Our results suggest that habitat fragmentation has increased genetic differentiation between Lesser Kestrel populations, following an Isolation-by-Distance pattern, while the population of Eurasian Kestrels is panmictic. Contrary to expectations, we did not detect significant evidence of reduced genetic variation or increased inbreeding in Lesser Kestrels. Although this study reports genetic differentiation in a species that has potential for long-Distance dispersal but philopatry-limited gene flow, large enough effective population sizes and migration may have been sufficient to mitigate genetic depauperation. A serious reduction of genetic diversity in Lesser Kestrels would, therefore, only be expected after severe population bottlenecks following extreme geographic Isolation.
Lorenz Hauser - One of the best experts on this subject based on the ideXlab platform.
-
population assignment and local adaptation along an Isolation by Distance gradient in pacific cod gadus macrocephalus
Evolutionary Applications, 2018Co-Authors: Daniel P Drinan, Kristen M Gruenthal, Michael F Canino, Dayv Lowry, Mary C Fisher, Lorenz HauserAbstract:: The discernment of populations as management units is a fundamental prerequisite for sustainable exploitation of species. A lack of clear stock boundaries complicates not only the identification of spatial management units, but also the assessment of mixed fisheries by population assignment and mixed stock analysis. Many marine species, such as Pacific cod, are characterized by Isolation by Distance, showing significant differentiation but no clear stock boundaries. Here, we used restriction-site-associated DNA (RAD) sequencing to investigate population structure and assess power to genetically assign Pacific cod to putative populations of origin. Samples were collected across the species range in the eastern Pacific Ocean, from the Salish Sea to the Aleutian Islands. A total of 6,425 putative biallelic single nucleotide polymorphisms were identified from 276 individuals. We found a strong Isolation-by-Distance signal along coastlines that mirrored previous microsatellite results and pronounced genetic differentiation between coastal samples and those from the inland waters of the Salish Sea, with no evidence for hybridization between these two populations. Individual assignment success based on two methods was high overall (≥84%) but decreased from south to north. Assignment to geographic location of origin also was successful, with average Distance between capture and assignment location of 220 km. Outlier analyses identified more loci potentially under selection along the coast than between Salish Sea and coastal samples, suggesting more diverse adaptation to latitudinal environmental factors than inshore vs. offshore environments. Our results confirm previous observations of sharp genetic differentiation of the Salish Sea population and Isolation by Distance along the coast, but also highlight the feasibility of using modern genomic techniques to inform stock boundaries and fisheries management in a low FST marine species.
-
genetic Isolation by Distance and localized fjord population structure in pacific cod gadus macrocephalus limited effective dispersal in the northeastern pacific ocean
Canadian Journal of Fisheries and Aquatic Sciences, 2009Co-Authors: Ingrid B Spies, Michael F Canino, Lorenz Hauser, Kathryn Maja Cunninghamk M CunninghamAbstract:Genetic population structure of Pacific cod, Gadus macrocephalus, was examined across much of its northeast- ern Pacific range by screening variation at 11 microsatellite DNA loci. Estimates of FST (0.005 ± 0.002) and RST (0.010 ± 0.003) over all samples suggested that effective dispersal is limited among populations. Genetic divergence was highly cor- related with geographic Distance in an Isolation-by-Distance (IBD) pattern along the entire coastal continuum in the north- eastern Pacific Ocean (~4000 km; r 2 = 0.83), extending from Washington State to the Aleutian Islands, and over smaller geographic Distances for three locations in Alaska (~1700 km; r 2 = 0.56). Slopes of IBD regressions suggested average dis- persal Distance between birth and reproduction of less than 30 km. Exceptions to this pattern were found in samples taken from fjord environments in the Georgia Basin (the Strait of Georgia (Canada) and Puget Sound (USA)), where populations were differentiated from coastal cod. Our results showed population structure at spatial scales relevant to fisheries manage- ment, both caused by limited dispersal along the coast and by sharp barriers to migration isolating smaller stocks in coastal fjord environments.
Terry Burke - One of the best experts on this subject based on the ideXlab platform.
-
using Isolation by Distance based approaches to assess the barrier effect of linear landscape elements on badger meles meles dispersal
Molecular Ecology, 2010Co-Authors: Alain C. Frantz, Lisa C Pope, Thomas R Etherington, Gavin J Wilson, Terry BurkeAbstract:As the European badger (Meles meles) can be of conservation or management concern, it is important to have a good understanding of the species' dispersal ability. In particular, knowledge of landscape elements that affect dispersal can contribute to devising effective management strategies. However, the standard approach of using Bayesian clustering methods to correlate genetic discontinuities with landscape elements cannot easily be applied to this problem, as badger populations are often characterized by a strong confounding Isolation-by-Distance (IBD) pattern. We therefore developed a two-step method that compares the location of pairs of related badgers relative to a putative barrier and utilizes the expected spatial genetic structure characterized by IBD as a null model to test for the presence of a barrier. If a linear feature disrupts dispersal, the IBD pattern characterising pairs of individuals located on different sides of a putative barrier should differ significantly from the pattern obtained with pairs of individuals located on the same side. We used our new approach to assess the impact of rivers and roads of different sizes on badger dispersal in western England. We show that a large, wide river represented a barrier to badger dispersal and found evidence that a motorway may also restrict badger movement. Conversely, we did not find any evidence for small rivers and roads interfering with badger movement. One of the advantages of our approach is that potentially it can detect features that disrupt gene flow locally, without necessarily creating distinct identifiable genetic units.
-
Using spatial Bayesian methods to determine the genetic structure of a continuously distributed population: clusters or Isolation by Distance?
Journal of Applied Ecology, 2009Co-Authors: Alain C. Frantz, S. Cellina, Ady Krier, Laurent Schley, Terry BurkeAbstract:Summary 1 Spatially explicit Bayesian clustering techniques offer a powerful tool for ecology and wildlife management, as genetic divisions can be correlated with landscape features. We used these methods to analyse the genetic structure of a population of European wild boar Sus scrofa with the aim of identifying effective barriers for disease management units. However, it has been suggested that the methods could produce biased results when faced with deviations from random mating not caused by genetic discontinuities, such as Isolation by Distance (IBD). 2 We analysed a data set consisting of 697 wild boar multilocus genotypes using spatially explicit (baps, geneland) and non-explicit (structure) Bayesian methods. We also simulated and analysed data sets characterized by different degrees of IBD, with and without genetic discontinuities. 3 When analysing the empirical data set, different programs did not converge on the same clustering solution and some clusters were difficult to explain biologically. Results from the simulated data showed that IBD, also present in the empirical data set, could cause the Bayesian methods to overestimate genetic structure. Simulated barriers were identified correctly, but the programs superimposed further clusters at higher IBD levels . 4 It was not possible to ascertain with confidence whether the clustering solutions offered by the various programs were an accurate reflection of population genetic structure in our empirical data set or were artefacts created by the underlying IBD pattern. 5 Synthesis and applications: We show that Bayesian clustering methods can overestimate genetic structure when analysing an individual-based data set characterized by Isolation by Distance. This bias could lead to the erroneous delimitation of management or conservation units. Investigators should be critical and suspicious of clusters that cannot be explained biologically. Data sets should be tested for Isolation by Distance and conclusions should not be based on the output from just one method.
-
Isolation by Distance and gene flow in the eurasian badger meles meles at both a local and broad scale
Molecular Ecology, 2005Co-Authors: Lisa C Pope, Xavier Domingoroura, Kristien Erven, Terry BurkeAbstract:Eurasian badgers, Meles meles, have been shown to possess limited genetic population structure within Europe; however, field studies have detected high levels of philopatry, which are expected to increase population structure. Population structure will be a consequence of both contemporary dispersal and historical processes, each of which is expected to be evident at a different scale. Therefore, to gain a greater understanding of gene flow in the badger, we examined microsatellite diversity both among and within badger populations, focusing on populations from the British Isles and western Europe. We found that while populations differed in their allelic diversity, the British Isles displayed a similar degree of diversity to the rest of western Europe. The lower genetic diversity occurring in Ireland, Norway and Scotland was more likely to have resulted from founder effects rather than contemporary population density. While there was significant population structure (F(ST) = 0.19), divergence among populations was generally well explained by geographic Distance (P < 0.0001) across the entire range studied of more than 3000 km. Transient effects from the Pleistocene appear to have been replaced by a strong pattern of genetic Isolation by Distance across western Europe, suggestive of colonization from a single refugium. Analysis of individuals within British populations through Mantel tests and spatial autocorrelation demonstrated that there was significant local population structure across 3-30 km, confirming that dispersal is indeed restricted. The Isolation by Distance observed among badger populations across western Europe is likely to be a consequence of this restricted local dispersal.
Miguel Alcaide - One of the best experts on this subject based on the ideXlab platform.
-
population fragmentation leads to Isolation by Distance but not genetic impoverishment in the philopatric lesser kestrel a comparison with the widespread and sympatric eurasian kestrel
Heredity, 2009Co-Authors: Miguel Alcaide, David Serrano, Toni Laaksonen, José Luis Tella, Juan J. Negro, C. Muller, Erkki KorpimäkiAbstract:Population fragmentation leads to Isolation by Distance but not genetic impoverishment in the philopatric Lesser Kestrel: a comparison with the widespread and sympatric Eurasian Kestrel
-
Population fragmentation leads to Isolation by Distance but not genetic impoverishment in the philopatric Lesser Kestrel: a comparison with the widespread and sympatric Eurasian Kestrel
Heredity, 2009Co-Authors: Miguel Alcaide, David Serrano, Toni Laaksonen, José Luis Tella, Juan J. Negro, C. Muller, A Gal, Erkki KorpimäkiAbstract:Population fragmentation is a widespread phenomenon usually associated with human activity. As a result of habitat transformation, the philopatric and steppe-specialist Lesser Kestrel Falco naumanni underwent a severe population decline during the last century that increased population fragmentation throughout its breeding range. In contrast, the ubiquitous Eurasian Kestrel Falco tinnunculus did not suffer such adverse effects, its breeding range still remaining rather continuous. Using microsatellites, we tested the effects of population fragmentation on large-scale spatial patterns of genetic differentiation and diversity by comparing these two sympatric and phylogenetically related species. Our results suggest that habitat fragmentation has increased genetic differentiation between Lesser Kestrel populations, following an Isolation-by-Distance pattern, while the population of Eurasian Kestrels is panmictic. Contrary to expectations, we did not detect significant evidence of reduced genetic variation or increased inbreeding in Lesser Kestrels. Although this study reports genetic differentiation in a species that has potential for long-Distance dispersal but philopatry-limited gene flow, large enough effective population sizes and migration may have been sufficient to mitigate genetic depauperation. A serious reduction of genetic diversity in Lesser Kestrels would, therefore, only be expected after severe population bottlenecks following extreme geographic Isolation.
Ingrid B Spies - One of the best experts on this subject based on the ideXlab platform.
-
where do we draw the line a simulation approach for evaluating management of marine fish stocks with Isolation by Distance stock structure
Canadian Journal of Fisheries and Aquatic Sciences, 2015Co-Authors: Paul D Spencer, Ingrid B Spies, André E. PuntAbstract:There is no established management protocol for stocks subject to Isolation-by-Distance (IBD) stock structure. This study examines several management strategies for two marine fish species subject to IBD using simulation: Pacific cod (Gadus macrocephalus) in the Aleutian Islands (AI) and northern rockfish (Sebastes polyspinis) in the Eastern Bering Sea (EBS) and AI. A one-dimensional stepping stone model was used to model IBD and was intended to mimic regions where marine species are exploited along a continental shelf. The performance of spatial assessment and management methods depended on how the range was split. Splitting anywhere within the managed area led to fewer demes falling below target and threshold biomass levels and higher yield than managing the entire area as a single unit. Equilibrium yield was maximized when each deme was assessed and managed separately and under catch cascading, in which harvest quotas within a management unit are spatially allocated based upon the distribution of surve...
-
genetic Isolation by Distance and localized fjord population structure in pacific cod gadus macrocephalus limited effective dispersal in the northeastern pacific ocean
Canadian Journal of Fisheries and Aquatic Sciences, 2009Co-Authors: Ingrid B Spies, Michael F Canino, Lorenz Hauser, Kathryn Maja Cunninghamk M CunninghamAbstract:Genetic population structure of Pacific cod, Gadus macrocephalus, was examined across much of its northeast- ern Pacific range by screening variation at 11 microsatellite DNA loci. Estimates of FST (0.005 ± 0.002) and RST (0.010 ± 0.003) over all samples suggested that effective dispersal is limited among populations. Genetic divergence was highly cor- related with geographic Distance in an Isolation-by-Distance (IBD) pattern along the entire coastal continuum in the north- eastern Pacific Ocean (~4000 km; r 2 = 0.83), extending from Washington State to the Aleutian Islands, and over smaller geographic Distances for three locations in Alaska (~1700 km; r 2 = 0.56). Slopes of IBD regressions suggested average dis- persal Distance between birth and reproduction of less than 30 km. Exceptions to this pattern were found in samples taken from fjord environments in the Georgia Basin (the Strait of Georgia (Canada) and Puget Sound (USA)), where populations were differentiated from coastal cod. Our results showed population structure at spatial scales relevant to fisheries manage- ment, both caused by limited dispersal along the coast and by sharp barriers to migration isolating smaller stocks in coastal fjord environments.
