7 results on '"Teske, Peter R."'
Search Results
2. 'Nested' cryptic diversity in a widespread marine ecosystem engineer: a challenge for detecting biological invasions
- Author
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Teske, Peter R, Rius, Marc, McQuaid, Christopher D, Styan, Craig A, Piggott, Maxine P, Benhissoune, Saïd, Fuentes-Grünewald, Claudio, Walls, Kathy, Page, Mike, Attard, Catherine RM, Cooke, Georgina M, McClusky, Claire F, Banks, Sam, Barker, Nigel P, Beheregaray, Luciano B, Teske, Peter R, Rius, Marc, McQuaid, Christopher D, Styan, Craig A, Piggott, Maxine P, Benhissoune, Saïd, Fuentes-Grünewald, Claudio, Walls, Kathy, Page, Mike, Attard, Catherine RM, Cooke, Georgina M, McClusky, Claire F, Banks, Sam, Barker, Nigel P, and Beheregaray, Luciano B
- Abstract
BACKGROUND Ecosystem engineers facilitate habitat formation and enhance biodiversity, but when they become invasive, they present a critical threat to native communities because they can drastically alter the receiving habitat. Management of such species thus needs to be a priority, but the poorly resolved taxonomy of many ecosystem engineers represents a major obstacle to correctly identifying them as being either native or introduced. We address this dilemma by studying the sea squirt Pyura stolonifera, an important ecosystem engineer that dominates coastal communities particularly in the southern hemisphere. Using DNA sequence data from four independently evolving loci, we aimed to determine levels of cryptic diversity, the invasive or native status of each regional population, and the most appropriate sampling design for identifying the geographic ranges of each evolutionary unit. RESULTS Extensive sampling in Africa, Australasia and South America revealed the existence of "nested" levels of cryptic diversity, in which at least five distinct species can be further subdivided into smaller-scale genetic lineages. The ranges of several evolutionary units are limited by well-documented biogeographic disjunctions. Evidence for both cryptic native diversity and the existence of invasive populations allows us to considerably refine our view of the native versus introduced status of the evolutionary units within Pyura stolonifera in the different coastal communities they dominate. CONCLUSIONS This study illustrates the degree of taxonomic complexity that can exist within widespread species for which there is little taxonomic expertise, and it highlights the challenges involved in distinguishing between indigenous and introduced populations. The fact that multiple genetic lineages can be native to a single geographic region indicates that it is imperative to obtain samples from as many different habitat types and biotic zones as possible when attempting to identify the s
- Published
- 2011
3. Mitochondrial DNA paradox: sex-specific genetic structure in a marine mussel - despite maternal inheritance and passive dispersal.
- Author
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Teske, Peter R., Papadopoulos, Isabelle, Barker, Nigel P., and McQuaid, Christopher D.
- Subjects
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GENES , *MOLECULAR genetics , *DNA , *MITOCHONDRIA , *HEREDITY - Abstract
Background: When genetic structure is identified using mitochondrial DNA (mtDNA), but no structure is identified using biparentally-inherited nuclear DNA, the discordance is often attributed to differences in dispersal potential between the sexes. Results: We sampled the intertidal rocky shore mussel Perna perna in a South African bay and along the nearby open coast, and sequenced maternally-inherited mtDNA (there is no evidence for paternally-inherited mtDNA in this species) and a biparentally-inherited marker. By treating males and females as different populations, we identified significant genetic structure on the basis of mtDNA data in the females only. Conclusions: This is the first study to report sex-specific differences in genetic structure based on matrilineallyinherited mtDNA in a passively dispersing species that lacks social structure or sexual dimorphism. The observed pattern most likely stems from females being more vulnerable to selection in habitats from which they did not originate, which also manifests itself in a male-biased sex ratio. Our results have three important implications for the interpretation of population genetic data. First, even when mtDNA is inherited exclusively in the female line, it also contains information about males. For that reason, using it to identify sex-specific differences in genetic structure by contrasting it with biparentally-inherited markers is problematic. Second, the fact that sex-specific differences were found in a passively dispersing species in which sex-biased dispersal is unlikely highlights the fact that significant genetic structure is not necessarily a function of low dispersal potential or physical barriers. Third, even though mtDNA is typically used to study historical demographic processes, it also contains information about contemporary processes. Higher survival rates of males in non-native habitats can erase the genetic structure present in their mothers within a single generation. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
4. "Nested" cryptic diversity in a widespread marine ecosystem engineer: a challenge for detecting biological invasions.
- Author
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Teske, Peter R., Rius, Marc, McQuaid, Christopher D., Styan, Craig A., Piggott, Maxine P., Benhissoune, Saïd, Fuentes-Grünewald, Claudio, Walls, Kathy, Page, Mike, Attard, Catherine R. M., Cooke, Georgina M., McClusky, Claire F., Banks, Sam C., Barker, Nigel P., and Beheregaray, Luciano B.
- Subjects
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HABITATS , *NUCLEOTIDE sequence , *BIOTIC communities , *DNA - Abstract
Background: Ecosystem engineers facilitate habitat formation and enhance biodiversity, but when they become invasive, they present a critical threat to native communities because they can drastically alter the receiving habitat. Management of such species thus needs to be a priority, but the poorly resolved taxonomy of many ecosystem engineers represents a major obstacle to correctly identifying them as being either native or introduced. We address this dilemma by studying the sea squirt Pyura stolonifera, an important ecosystem engineer that dominates coastal communities particularly in the southern hemisphere. Using DNA sequence data from four independently evolving loci, we aimed to determine levels of cryptic diversity, the invasive or native status of each regional population, and the most appropriate sampling design for identifying the geographic ranges of each evolutionary unit. Results: Extensive sampling in Africa, Australasia and South America revealed the existence of "nested" levels of cryptic diversity, in which at least five distinct species can be further subdivided into smaller-scale genetic lineages. The ranges of several evolutionary units are limited by well-documented biogeographic disjunctions. Evidence for both cryptic native diversity and the existence of invasive populations allows us to considerably refine our view of the native versus introduced status of the evolutionary units within Pyura stolonifera in the different coastal communities they dominate. Conclusions: This study illustrates the degree of taxonomic complexity that can exist within widespread species for which there is little taxonomic expertise, and it highlights the challenges involved in distinguishing between indigenous and introduced populations. The fact that multiple genetic lineages can be native to a single geographic region indicates that it is imperative to obtain samples from as many different habitat types and biotic zones as possible when attempting to identify the source region of a putative invader. "Nested" cryptic diversity, and the difficulties in correctly identifying invasive species that arise from it, represent a major challenge for managing biodiversity. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
5. 'Nested' cryptic diversity in a widespread marine ecosystem engineer: a challenge for detecting biological invasions
- Author
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Claudio Fuentes-Grünewald, Craig A. Styan, Saïd Benhissoune, Michael J. Page, Christopher D. McQuaid, Marc Rius, Kathy Walls, Catherine R. M. Attard, Nigel P. Barker, Luciano B. Beheregaray, Peter R. Teske, Georgina M. Cooke, Sam C. Banks, Maxine P. Piggott, Claire F. McClusky, Teske, Peter R, Rius, Marc, McQuaid, Christopher D, Styan, Craig A, Piggott, Maxine P, Benhissoune, Sad, Fuentes-Grünewald, Claudio, Walls, Kathy, Page, Mike, Attard, Catherine RM, Cooke, Georgina M, McClusky, Claire F, Banks, Sam C, Barker, Nigel P, Beheregaray, Luciano B, Department of Biological Sciences, and Faculty of Science
- Subjects
Pyura stolonifera ,Evolution ,Cryptic diversity ,Population ,Molecular Sequence Data ,Biodiversity ,Introduced species ,Marine Biology ,Ecosystem engineer ,Taxonomic complexity ,QH359-425 ,Animals ,Marine ecosystem ,Ecosystem ,Urochordata ,education ,Ecology, Evolution, Behavior and Systematics ,Phylogeny ,education.field_of_study ,biology ,Ecology ,Taxonomic expertise ,habitat formation ,biology.organism_classification ,Biological Evolution ,Habitat ,Evolutionary biology ,Introduced Species ,Research Article - Abstract
Teske et al..-- 13 pages, 1 figure, 4 tables, additional material in https://doi.org/10.1186/1471-2148-11-176 Background Ecosystem engineers facilitate habitat formation and enhance biodiversity, but when they become invasive, they present a critical threat to native communities because they can drastically alter the receiving habitat. Management of such species thus needs to be a priority, but the poorly resolved taxonomy of many ecosystem engineers represents a major obstacle to correctly identifying them as being either native or introduced. We address this dilemma by studying the sea squirt Pyura stolonifera, an important ecosystem engineer that dominates coastal communities particularly in the southern hemisphere. Using DNA sequence data from four independently evolving loci, we aimed to determine levels of cryptic diversity, the invasive or native status of each regional population, and the most appropriate sampling design for identifying the geographic ranges of each evolutionary unit. Results Extensive sampling in Africa, Australasia and South America revealed the existence of "nested" levels of cryptic diversity, in which at least five distinct species can be further subdivided into smaller-scale genetic lineages. The ranges of several evolutionary units are limited by well-documented biogeographic disjunctions. Evidence for both cryptic native diversity and the existence of invasive populations allows us to considerably refine our view of the native versus introduced status of the evolutionary units within Pyura stolonifera in the different coastal communities they dominate. Conclusions This study illustrates the degree of taxonomic complexity that can exist within widespread species for which there is little taxonomic expertise, and it highlights the challenges involved in distinguishing between indigenous and introduced populations. The fact that multiple genetic lineages can be native to a single geographic region indicates that it is imperative to obtain samples from as many different habitat types and biotic zones as possible when attempting to identify the source region of a putative invader. "Nested" cryptic diversity, and the difficulties in correctly identifying invasive species that arise from it, represent a major challenge for managing biodiversity PR Teske was supported by a postdoctoral research fellowship for overseas study by the National Research Foundation, an overseas study grant from the Ernest Oppenheimer Memorial Trust and a Rhodes University postdoctoral research fellowship. M Rius was supported by the 'Agencia Española de Cooperación Internacional para el Desarrollo' from the Spanish 'Ministerio de Asuntos Exteriores y de Cooperación'. The work was partially funded by a grant from the DST-NRF Centre of Excellence for Invasion Biology (to M Rius), by the South African Research Chairs Initiative of the Department of Science and Technology and the National Research Foundation (to CD McQuaid), by grants from Macquarie University (MQ A006162) and the Australian Research Council (DP110101275) to LB Beheregaray, and by Flinders University. This contribution represents manuscript no. 40 of the Molecular Ecology Group for Marine Research (MEGMAR)
- Published
- 2011
6. Oceanic dispersal barriers, adaptation and larval retention: an interdisciplinary assessment of potential factors maintaining a phylogeographic break between sister lineages of an African prawn.
- Author
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Teske PR, Papadopoulos I, Newman BK, Dworschak PC, McQuaid CD, and Barker NP
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- Africa, Animal Migration, Animals, Decapoda classification, Decapoda growth & development, Gene Flow, Genetics, Population, Haplotypes, Larva genetics, Oceans and Seas, Temperature, Decapoda genetics, Genetic Speciation, Phylogeny
- Abstract
Background: Genetic breaks separating regional lineages of marine organisms with potentially high broadcasting abilities are generally attributed either to dispersal barriers such as currents or upwelling, or to behavioural strategies promoting self-recruitment. We investigated whether such patterns could potentially also be explained by adaptations to different environmental conditions by studying two morphologically distinguishable genetic lineages of the estuarine mudprawn Upogebia africana across a biogeographic disjunction in south-eastern Africa. The study area encompasses a transition between temperate and subtropical biotas, where the warm, southward-flowing Agulhas Current is deflected away from the coast, and its inshore edge is characterised by intermittent upwelling. To determine how this phylogeographic break is maintained, we estimated gene flow among populations in the region, tested for isolation by distance as an indication of larval retention, and reared larvae of the temperate and subtropical lineages at a range of different temperatures., Results: Of four populations sampled, the two northernmost exclusively included the subtropical lineage, a central population had a mixture of both lineages, and the southernmost estuary had only haplotypes of the temperate lineage. No evidence was found for isolation by distance, and gene flow was bidirectional and of similar magnitude among adjacent populations. In both lineages, the optimum temperature for larval development was at about 23 degrees C, but a clear difference was found at lower temperatures. While larvae of the temperate lineage could complete development at temperatures as low as 12 degrees C, those of the subtropical lineage did not complete development below 17 degrees C., Conclusion: The results indicate that both southward dispersal of the subtropical lineage inshore of the Agulhas Current, and its establishment in the temperate province, may be limited primarily by low water temperatures. There is no evidence that the larvae of the temperate lineage would survive less well in the subtropical province than in their native habitat, and their exclusion from this region may be due to a combination of upwelling, short larval duration with limited dispersal potential near the coast, plus transport away from the coast of larvae that become entrained in the Agulhas Current. This study shows how methods from different fields of research (genetics, physiology, oceanography and morphology) can be combined to study phylogeographic patterns.
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- 2008
- Full Text
- View/download PDF
7. Signatures of seaway closures and founder dispersal in the phylogeny of a circumglobally distributed seahorse lineage.
- Author
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Teske PR, Hamilton H, Matthee CA, and Barker NP
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Cytochromes b genetics, Genetic Markers, Likelihood Functions, RNA, Ribosomal, 16S genetics, Ribosomal Proteins genetics, Sequence Alignment, Evolution, Molecular, Founder Effect, Genetic Speciation, Phylogeny, Smegmamorpha genetics
- Abstract
Background: The importance of vicariance events on the establishment of phylogeographic patterns in the marine environment is well documented, and generally accepted as an important cause of cladogenesis. Founder dispersal (i.e. long-distance dispersal followed by founder effect speciation) is also frequently invoked as a cause of genetic divergence among lineages, but its role has long been challenged by vicariance biogeographers. Founder dispersal is likely to be common in species that colonize remote habitats by means of rafting (e.g. seahorses), as long-distance dispersal events are likely to be rare and subsequent additional recruitment from the source habitat is unlikely. In the present study, the relative importance of vicariance and founder dispersal as causes of cladogenesis in a circumglobally distributed seahorse lineage was investigated using molecular dating. A phylogeny was reconstructed using sequence data from mitochondrial and nuclear markers, and the well-documented closure of the Central American seaway was used as a primary calibration point to test whether other bifurcations in the phylogeny could also have been the result of vicariance events. The feasibility of three other vicariance events was explored: a) the closure of the Indonesian Seaway, resulting in sister lineages associated with the Indian Ocean and West Pacific, respectively; b) the closure of the Tethyan Seaway, resulting in sister lineages associated with the Indo-Pacific and Atlantic Ocean, respectively, and c) continental break-up during the Mesozoic followed by spreading of the Atlantic Ocean, resulting in pairs of lineages with amphi-Atlantic distribution patterns., Results: Comparisons of pairwise genetic distances among the seahorse species hypothesized to have diverged as a result of the closure of the Central American Seaway with those of published teleost sequences having the same distribution patterns show that the seahorses were among the last to diverge. This suggests that their cladogenesis was associated with the final closure of this seaway. Although two other divergence events in the phylogeny could potentially have arisen as a result of the closures of the Indonesian and Tethyan seaways, respectively, the timing of the majority of bifurcations in the phylogeny differed significantly from the dates of vicariance events suggested in the literature. Moreover, several divergence events that resulted in the same distribution patterns of lineages at different positions in the phylogeny did not occur contemporaneously. For that reason, they cannot be the result of the same vicariance events, a result that is independent of molecular dating., Conclusion: Interpretations of the cladogenetic events in the seahorse phylogeny based purely on vicariance biogeographic hypotheses are problematic. We conclude that the evolution of the circumglobally distributed seahorse lineage was strongly influenced by founder dispersal, and suggest that this mode of speciation may be particularly important in marine organisms that lack a pelagic dispersal phase and instead disperse by means of rafting.
- Published
- 2007
- Full Text
- View/download PDF
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