Browsing by Author "Riginos C"

Now showing 1 - 17 of 17
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    A novel widespread cryptic species and phylogeographic patterns within several giant clam species (Cardiidae: Tridacna) from the Indo-Pacific Ocean.
    (PUBLIC LIBRARY SCIENCE, 2013) Huelsken T; Keyse J; Liggins L; Penny S; Treml EA; Riginos C
    Giant clams (genus Tridacna) are iconic coral reef animals of the Indian and Pacific Oceans, easily recognizable by their massive shells and vibrantly colored mantle tissue. Most Tridacna species are listed by CITES and the IUCN Redlist, as their populations have been extensively harvested and depleted in many regions. Here, we survey Tridacna crocea and Tridacna maxima from the eastern Indian and western Pacific Oceans for mitochondrial (COI and 16S) and nuclear (ITS) sequence variation and consolidate these data with previous published results using phylogenetic analyses. We find deep intraspecific differentiation within both T. crocea and T. maxima. In T. crocea we describe a previously undocumented phylogeographic division to the east of Cenderawasih Bay (northwest New Guinea), whereas for T. maxima the previously described, distinctive lineage of Cenderawasih Bay can be seen to also typify western Pacific populations. Furthermore, we find an undescribed, monophyletic group that is evolutionarily distinct from named Tridacna species at both mitochondrial and nuclear loci. This cryptic taxon is geographically widespread with a range extent that minimally includes much of the central Indo-Pacific region. Our results reinforce the emerging paradigm that cryptic species are common among marine invertebrates, even for conspicuous and culturally significant taxa. Additionally, our results add to identified locations of genetic differentiation across the central Indo-Pacific and highlight how phylogeographic patterns may differ even between closely related and co-distributed species.
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    Building a global genomics observatory: Using GEOME (the Genomic Observatories Metadatabase) to expedite and improve deposition and retrieval of genetic data and metadata for biodiversity research.
    (2020-11) Riginos C; Crandall ED; Liggins L; Gaither MR; Ewing RB; Meyer C; Andrews KR; Euclide PT; Titus BM; Therkildsen NO; Salces-Castellano A; Stewart LC; Toonen RJ; Deck J
    Genetic data represent a relatively new frontier for our understanding of global biodiversity. Ideally, such data should include both organismal DNA-based genotypes and the ecological context where the organisms were sampled. Yet most tools and standards for data deposition focus exclusively either on genetic or ecological attributes. The Genomic Observatories Metadatabase (GEOME: geome-db.org) provides an intuitive solution for maintaining links between genetic data sets stored by the International Nucleotide Sequence Database Collaboration (INSDC) and their associated ecological metadata. GEOME facilitates the deposition of raw genetic data to INSDCs sequence read archive (SRA) while maintaining persistent links to standards-compliant ecological metadata held in the GEOME database. This approach facilitates findable, accessible, interoperable and reusable data archival practices. Moreover, GEOME enables data management solutions for large collaborative groups and expedites batch retrieval of genetic data from the SRA. The article that follows describes how GEOME can enable genuinely open data workflows for researchers in the field of molecular ecology.
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    Comparative phylogeography in the genomic age: Opportunities and challenges
    (John Wiley and Sons Ltd, 2022-12) McGaughran A; Liggins L; Marske KA; Dawson MN; Schiebelhut LM; Lavery SD; Knowles LL; Moritz C; Riginos C; Byrne M
    Aim: We consider the opportunities and challenges comparative phylogeography (CP) faces in the genomic age to determine: (1) how we can maximise the potential of big CP analyses to advance biogeographic and macroevolutionary theory; and (2) what we can, and will struggle, to achieve using CP approaches in this era of genomics. Location: World-wide. Taxon: All. Methods: We review the literature to discuss the future of CP - particularly examining CP insights enabled by genomics that may not be possible for single species and/or few molecular markers. We focus on how geography and species' natural histories interact to yield congruent and incongruent patterns of neutral and adaptive processes in the context of both historical and recent rapid evolution. We also consider how CP genomic data are being stored, accessed, and shared. Results: With the widespread availability of genomic data, the shift from a single- to a multi-locus perspective is resulting in detailed historical inferences and an improved statistical rigour in phylogeography. However, the time and effort required for collecting co-distributed species and accruing species-specific ecological knowledge continue to be limiting factors. Bioinformatic skills and user-friendly analytical tools, alongside the computational infrastructure required for big data, can also be limiting. Main conclusions: Over the last ~35 years, there has been much progress in understanding how intraspecific genetic variation is geographically distributed. The next major steps in CP will be to incorporate evolutionary processes and community perspectives to account for patterns and responses among co-distributed species and across temporal scales, including those related to anthropogenic change. However, the full potential of CP will only be realised if we employ robust study designs within a sound comparative framework. We advocate that phylogeographers adopt such consistent approaches to enhance future comparisons to present-day findings.
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    Evaluating edge-of-range genetic patterns for tropical echinoderms, Acanthaster planci and Tripneustes gratilla, of the Kermadec Islands, southwest Pacific
    (ROSENSTIEL SCH MAR ATMOS SCI, 1/01/2014) Liggins L; Gleeson L; Riginos C
    Edge-of-range populations are often typified by patterns of low genetic diversity and high genetic differentiation relative to populations within the core of a species range. The "core-periphery hypothesis," also known as the "central-marginal hypothesis," predicts that these genetic patterns at the edge-of-range are a consequence of reduced population size and connectivity toward a species range periphery. It is unclear, however, how these expectations relate to high dispersal marine species that can conceivably maintain high abundance and high connectivity at their range edge. In the present study, we characterize the genetic patterns of two tropical echinoderm populations in the Kermadec Islands, the edge of their southwest Pacific range, and compare these genetic patterns to those from populations throughout their east Indian and Pacific ranges. We find that the populations of both Acanthaster planci (Linnaeus, 1758) and Tripneustes gratilla (Linnaeus, 1758) are represented by a single haplotype at the Kermadec Islands (based on mitochondrial cytochrome oxidase C subunit I). Such low genetic diversity concurs with the expectations of the "core-periphery hypothesis." Furthermore, the haplotypic composition of both populations suggests they have been founded by a small number of colonists with little subsequent immigration. Thus, local reproduction and self-recruitment appear to maintain these populations despite the ecologically marginal conditions of the Kermadec Islands for these tropical species. Understanding rates of self-recruitment vs reliance on connectivity with populations outside of the Kermadec Islands has implications for the persistence of these populations and range stability of these echinoderm species.© 2014 Rosenstiel School of Marine and Atmospheric Science of the University of Miami.
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    Importance of timely metadata curation to the global surveillance of genetic diversity
    (Wiley Periodicals LLC on behalf of Society for Conservation Biology, 2023-08) Crandall ED; Toczydlowski RH; Liggins L; Holmes AE; Ghoojaei M; Gaither MR; Wham BE; Pritt AL; Noble C; Anderson TJ; Barton RL; Berg JT; Beskid SG; Delgado A; Farrell E; Himmelsbach N; Queeno SR; Trinh T; Weyand C; Bentley A; Deck J; Riginos C; Bradburd GS; Toonen RJ
    Genetic diversity within species represents a fundamental yet underappreciated level of biodiversity. Because genetic diversity can indicate species resilience to changing climate, its measurement is relevant to many national and global conservation policy targets. Many studies produce large amounts of genome-scale genetic diversity data for wild populations, but most (87%) do not include the associated spatial and temporal metadata necessary for them to be reused in monitoring programs or for acknowledging the sovereignty of nations or Indigenous peoples. We undertook a distributed datathon to quantify the availability of these missing metadata and to test the hypothesis that their availability decays with time. We also worked to remediate missing metadata by extracting them from associated published papers, online repositories, and direct communication with authors. Starting with 848 candidate genomic data sets (reduced representation and whole genome) from the International Nucleotide Sequence Database Collaboration, we determined that 561 contained mostly samples from wild populations. We successfully restored spatiotemporal metadata for 78% of these 561 data sets (n = 440 data sets with data on 45,105 individuals from 762 species in 17 phyla). Examining papers and online repositories was much more fruitful than contacting 351 authors, who replied to our email requests 45% of the time. Overall, 23% of our email queries to authors unearthed useful metadata. The probability of retrieving spatiotemporal metadata declined significantly as age of the data set increased. There was a 13.5% yearly decrease in metadata associated with published papers or online repositories and up to a 22% yearly decrease in metadata that were only available from authors. This rapid decay in metadata availability, mirrored in studies of other types of biological data, should motivate swift updates to data-sharing policies and researcher practices to ensure that the valuable context provided by metadata is not lost to conservation science forever. Importancia de la curación oportuna de metadatos para la vigilancia mundial de ladiversidad genéticaResumen:La diversidad genética intraespecífica representa un nivel fundamental, pero ala vez subvalorado de la biodiversidad. La diversidad genética puede indicar la resilienciade una especie ante el clima cambiante, por lo que su medición es relevante para muchosobjetivos de la política de conservación mundial y nacional. Muchos estudios producenuna gran cantidad de datos sobre la diversidad a nivel genético de las poblaciones silvestres,aunque la mayoría (87%) no incluye los metadatos espaciales y temporales asociados paraque sean reutilizados en los programas de monitoreo o para reconocer la soberanía de lasnaciones o los pueblos indígenas. Realizamos un “datatón” distribuido para cuantificar ladisponibilidad de estos metadatos faltantes y para probar la hipótesis que supone que estadisponibilidad se deteriora con el tiempo. También trabajamos para reparar los metadatosfaltantes al extraerlos de los artículos asociados publicados, los repositorios en línea yla comunicación directa con los autores. Iniciamos con 838 candidatos de conjuntos dedatos genómicos (representación reducida y genoma completo) tomados de la colabo-ración internacional para la base de datos de secuencias de nucleótidos y determinamosque 561 incluían en su mayoría muestras tomadas de poblaciones silvestres. Restauramoscon éxito los metadatos espaciotemporales en el 78% de estos 561 conjuntos de datos (n=440 conjuntos de datos con información sobre 45,105 individuos de 762 especies en 17filos). El análisis de los artículos y los repositorios virtuales fue mucho más productivo quecontactar a los 351 autores, quienes tuvieron un 45% de respuesta a nuestros correos. Engeneral, el 23% de nuestras consultas descubrieron metadatos útiles. La probabilidad derecuperar metadatos espaciotemporales declinó de manera significativa conforme incre-mentó la antigüedad del conjunto de datos. Hubo una disminución anual del 13.5% enlos metadatos asociados con los artículos publicados y los repositorios virtuales y hastauna disminución anual del 22% en los metadatos que sólo estaban disponibles mediante lacomunicación con los autores. Este rápido deterioro en la disponibilidad de los metadatos,duplicado en estudios de otros tipos de datos biológicos, debería motivar la pronta actual-ización de las políticas del intercambio de datos y las prácticas de los investigadores paraasegurar que en las ciencias de la conservación no se pierda para siempre el contexto valiosoproporcionado por los metadatos.
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    Larval traits show temporally consistent constraints, but are decoupled from postsettlement juvenile growth, in an intertidal fish
    (John Wiley and Sons, Inc on behalf of the British Ecological Society, 8/08/2018) Thia JA; Riginos C; Liggins L; Figueira WF; McGuigan K
    1. Complex life cycles may evolve to dissociate distinct developmental phases in an organism's lifetime. However, genetic or environmental factors may restrict trait independence across life stages, constraining ontogenetic trajectories. Quantifying covariance across life stages and their temporal variability is fundamental in understanding life-history phenotypes and potential distributions and consequences for selection. 2. We studied developmental constraints in an intertidal fish (Bathygobius cocosensis: Gobiidae) with a discrete pelagic larval phase and benthic juvenile phase. We tested whether traits occurring earlier in life affected those expressed later, and whether larval traits were decoupled from postsettlement juvenile traits. Sampling distinct cohorts from three annual breeding seasons afforded tests of temporally variability in trait covariance. 3. From otoliths (fish ear stones), we measured hatch size, larval duration, pelagic growth (larval traits) and early postsettlement growth (juvenile trait) in 124 juvenile B. cocoensis. We used path analyses to model trait relationships with respect to their chronological expression, comparing models among seasons. We also modelled the effect of season and hatch date on each individual trait to quantify their inherent variability. 4. Our path analyses demonstrated a decoupling of larval traits on juvenile growth. Within the larval phase, longer larval durations resulted in greater pelagic growth, and larger size-at-settlement. There was also evidence that larger hatch size might reduce larval durations, but this effect was only marginally significant. Although pelagic and postsettlement growth were decoupled, pelagic growth had postsettlement consequences: individuals with high pelagic growth were among the largest fish at settlement, and remained among the largest early postsettlement. We observed no evidence that trait relationships varied among breeding seasons, but larval duration differed among breeding seasons, and was shorter for larvae hatching later within each season. 5. Overall, we demonstrate mixed support for the expectation that traits in different life stages are independent. While postsettlement growth was decoupled from larval traits, pelagic development had consequences for the size of newly settled juveniles. Temporal consistency in trait covariances implies that genetic and/or environmental factors influencing them were stable over our three-year study. Our work highlights the importance of individual developmental experiences and temporal variability in understanding population distributions of life-history traits.
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    Latitude-wide genetic patterns reveal historical effects and contrasting patterns of turnover and nestedness at the range peripheries of a tropical marine fish
    (Blackwell Publishing Ltd, 1/12/2015) Liggins L; Booth DJ; Figueira WF; Treml EA; Tonk L; Ridgway T; Harris DA; Riginos C
    Few studies have examined core-periphery genetic patterns in tropical marine taxa. The core-periphery hypothesis (CPH) predicts that core populations will have higher genetic diversity and lower genetic differentiation than peripheral populations as a consequence of greater population sizes and population connectivity in the core. However, the applicability of the CPH to many tropical marine taxa may be confounded by their complex population histories and/or high (asymmetric) population connectivity. In this study we investigated genetic patterns (based on mtDNA) across the latitudinal range of the neon damselfish Pomacentrus coelestis (36°N, Japan - 37°S, east Australia). We suggest a novel hypothetical framework for core-periphery genetic patterns and extend typical analyses to include genealogical analyses, partitioned β-diversity measures (total βSOR, turnover βSIM, and nestedness-resultant βSNE), and analyses of nestedness. We found that the existence of two divergent lineages of the neon damselfish led levels of genetic diversity to deviate from CPH expectations. When focusing on the widespread lineage (Pacific clade) nucleotide diversity was higher in the core, supporting the CPH. However, genetic patterns differed toward the northern and southern peripheries of the Pacific clade. The turnover of haplotypes (pairwise-βsim) increased over distance in the north, indicative of historical colonization with little contemporary migration. In contrast, although turnover was still dominant in the south (βSIM), there was no relationship to distance (pairwise-βsim), suggesting the influence of more contemporary processes. Moreover, the haplotype compositions of populations in the south were nested according to latitude, indicating immigration from lower latitudes toward the southern periphery. By extending the typical characterizations of core-periphery genetic patterns we were able to identify the effects of lineage sympatry on measures of genetic diversity and contrasting demographic histories toward the latitudinal peripheries of the neon damselfish's range. Ecography
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    Metadata preservation and stewardship for genomic data is possible, but must happen now
    (2022-09-15) Crandall ED; Toczydlowski RH; Liggins L; Holmes AE; Ghoojaei M; Gaither MR; Wham BE; Pritt AL; Noble C; Anderson TJ; Barton RL; Berg JT; Beskid SG; Delgado A; Farrell E; Himmelsbach N; Queeno SR; Trinh T; Weyand C; Bentley A; Deck J; Riginos C; Bradburd GS; Toonen RJ
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    Navigating the currents of seascape genomics: how spatial analyses can augment population genomic studies.
    (2016-12) Riginos C; Crandall ED; Liggins L; Bongaerts P; Treml EA
    Population genomic approaches are making rapid inroads in the study of non-model organisms, including marine taxa. To date, these marine studies have predominantly focused on rudimentary metrics describing the spatial and environmental context of their study region (e.g., geographical distance, average sea surface temperature, average salinity). We contend that a more nuanced and considered approach to quantifying seascape dynamics and patterns can strengthen population genomic investigations and help identify spatial, temporal, and environmental factors associated with differing selective regimes or demographic histories. Nevertheless, approaches for quantifying marine landscapes are complicated. Characteristic features of the marine environment, including pelagic living in flowing water (experienced by most marine taxa at some point in their life cycle), require a well-designed spatial-temporal sampling strategy and analysis. Many genetic summary statistics used to describe populations may be inappropriate for marine species with large population sizes, large species ranges, stochastic recruitment, and asymmetrical gene flow. Finally, statistical approaches for testing associations between seascapes and population genomic patterns are still maturing with no single approach able to capture all relevant considerations. None of these issues are completely unique to marine systems and therefore similar issues and solutions will be shared for many organisms regardless of habitat. Here, we outline goals and spatial approaches for landscape genomics with an emphasis on marine systems and review the growing empirical literature on seascape genomics. We review established tools and approaches and highlight promising new strategies to overcome select issues including a strategy to spatially optimize sampling. Despite the many challenges, we argue that marine systems may be especially well suited for identifying candidate genomic regions under environmentally mediated selection and that seascape genomic approaches are especially useful for identifying robust locus-by-environment associations.
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    Not the time or the place: the missing spatio-temporal link in publicly available genetic data.
    (Blackwell Publishing Ltd, 2015-08) Pope LC; Liggins L; Keyse J; Carvalho SB; Riginos C
    Genetic data are being generated at unprecedented rates. Policies of many journals, institutions and funding bodies aim to ensure that these data are publicly archived so that published results are reproducible. Additionally, publicly archived data can be 'repurposed' to address new questions in the future. In 2011, along with other leading journals in ecology and evolution, Molecular Ecology implemented mandatory public data archiving (the Joint Data Archiving Policy). To evaluate the effect of this policy, we assessed the genetic, spatial and temporal data archived for 419 data sets from 289 articles in Molecular Ecology from 2009 to 2013. We then determined whether archived data could be used to reproduce analyses as presented in the manuscript. We found that the journal's mandatory archiving policy has had a substantial positive impact, increasing genetic data archiving from 49 (pre-2011) to 98% (2011-present). However, 31% of publicly archived genetic data sets could not be recreated based on information supplied in either the manuscript or public archives, with incomplete data or inconsistent codes linking genetic data and metadata as the primary reasons. While the majority of articles did provide some geographic information, 40% did not provide this information as geographic coordinates. Furthermore, a large proportion of articles did not contain any information regarding date of sampling (40%). Although the inclusion of spatio-temporal data does require an increase in effort, we argue that the enduring value of publicly accessible genetic data to the molecular ecology field is greatly compromised when such metadata are not archived alongside genetic data.
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    Poor data stewardship will hinder global genetic diversity surveillance.
    (24/08/2021) Toczydlowski RH; Liggins L; Gaither MR; Anderson TJ; Barton RL; Berg JT; Beskid SG; Davis B; Delgado A; Farrell E; Ghoojaei M; Himmelsbach N; Holmes AE; Queeno SR; Trinh T; Weyand CA; Bradburd GS; Riginos C; Toonen RJ; Crandall ED
    Genomic data are being produced and archived at a prodigious rate, and current studies could become historical baselines for future global genetic diversity analyses and monitoring programs. However, when we evaluated the potential utility of genomic data from wild and domesticated eukaryote species in the world's largest genomic data repository, we found that most archived genomic datasets (86%) lacked the spatiotemporal metadata necessary for genetic biodiversity surveillance. Labor-intensive scouring of a subset of published papers yielded geospatial coordinates and collection years for only 33% (39% if place names were considered) of these genomic datasets. Streamlined data input processes, updated metadata deposition policies, and enhanced scientific community awareness are urgently needed to preserve these irreplaceable records of today's genetic biodiversity and to plug the growing metadata gap.
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    Regional patterns of mtDNA diversity in Styela plicata, an invasive ascidian, from Australian and New Zealand marinas
    (CSIRO PUBLISHING, 7/03/2013) Torkkola J; Riginos C; Liggins L
    The ascidian Styela plicata is abundant in harbours and marinas worldwide and has likely reached this distribution via human-mediated dispersal. Previous worldwide surveys based on mitochondrial cytochrome oxidase one (COI) sequences have described two divergent clades, showing overlapping distributions and geographically widespread haplotypes. These patterns are consistent with recent mixing among genetically differentiated groups arising from multiple introductions from historically distinct sources. In contrast, a study of Australian S. plicata using nuclear markers found that population differentiation along the eastern coast related to geographic distance and no evidence for admixture between previously isolated genetic groups. We re-examined the genetic patterns of Australian S. plicata populations using mtDNA (CO1) to place their genetic patterns within a global context, and we examined New Zealand populations for the first time. We found that the haplotypic compositions of Australian and New Zealand populations are largely representative of other worldwide populations. The New Zealand populations, however, exhibited reduced diversity, being potentially indicative of a severely bottlenecked colonisation event. In contrast to results from nuclear markers, population differentiation of mtDNA among Australian S. plicata was unrelated to geographic distance. The discrepancy between markers is likely to be a consequence of non-equilibrium population genetic processes that typify non-indigenous species. © 2013 CSIRO.
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    Return of the ghosts of dispersal past: Historical spread and contemporary gene flow in the blue sea star Linckia laevigata
    (ROSENSTIEL SCH MAR ATMOS SCI, 1/01/2014) Crandall ED; Treml EA; Liggins L; Gleeson L; Yasuda N; Barber PH; Wörheide G; Riginos C
    Marine animals inhabiting the Indian and Pacific oceans have some of the most extensive species ranges in the world, sometimes spanning over half the globe. These Indo-Pacific species present a challenge for study with both geographic scope and sampling density as limiting factors. Here, we augment and aggregate phylogeographic sampling of the iconic blue sea star, Linckia laevigata Linnaeus, 1758, and present one of the most geographically comprehensive genetic studies of any Indo-Pacific species to date, sequencing 392 base pairs of mitochondrial COI from 791 individuals from 38 locations spanning over 14,000 km. We first use a permutation based multiple-regression approach to simultaneously evaluate the relative influence of historical and contemporary gene flow together with putative barriers to dispersal. We then use a discrete diffusion model of phylogeography to infer the historical migration and colonization routes most likely used by L. laevigata across the Indo-Pacific. We show that estimates of genetic structure have a stronger correlation to geographic distances than to "oceanographic" distances from a biophysical model of larval dispersal, reminding us that population genetic estimates of gene flow and genetic structure are often shaped by historical processes. While the diffusion model was equivocal about the location of the mitochondrial most recent common ancestor (MRC A), we show that gene flow has generally proceeded in a step-wise manner across the Indian and Pacific oceans. We do not find support for previously described barriers at the Sunda Shelf and within Cenderwasih Bay. Rather, the strongest genetic disjunction is found to the east of Cenderwasih Bay along northern New Guinea. These results underscore the importance of comprehensive range-wide sampling in marine phylogeography.© 2014 Rosenstiel School of Marine and Atmospheric Science of the University of Miami.
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    Seascape features, rather than dispersal traits, predict spatial genetic patterns in co-distributed reef fishes
    (Wiley, 2015) Liggins L; Treml EA; Possingham HP; Riginos C
    Aim: To determine which seascape features have shaped the spatial genetic patterns of coral reef fishes, and to identify common patterns among species related to dispersal traits [egg type and pelagic larval duration (PLD)]. Location: Indian and Pacific Oceans, including the Indo-Australian Archipelago. Methods: We sampled coral reef fishes with differing dispersal traits (Pomacentrus coelestis, Dascyllus trimaculatus, Hailchoeres hortulanus and Acanthurus triostegus) and characterized spatial (mtDNA) genetic patterns using AMOVA-clustering and measures of genetic differentiation. Similarity in the spatial genetic patterns among species was assessed using the congruence among distance matrices method and the seascape features associated with the genetic differentiation of each species were identified using multiple regression of distance matrices (MRDM) and stepwise model selection. Results: Similar spatial genetic patterns were found for P. coelestis and H. hortulanus, despite their differing egg type (benthic versus pelagic). MRDM indicated that geographical distance was underlying their correlated genetic patterns. Species with pelagic eggs (A. triostegus and H. hortulanus) also had correlated patterns of genetic differentiation (Dest); however, a common underlying seascape feature could not be inferred. Additionally, the common influence of the Torres Strait and the Lydekker/Weber's line was identified for the genetic patterns of differentiation for P. coelestis and A. triostegus, despite their differing dispersal traits, and the uncorrelated spatial genetic patterns of these species. Main conclusions: Our study demonstrates the value of a quantitative, hypothesis-testing framework in comparative phylogeography. We found that dispersal traits (egg type and PLD) did not predict which species had similar spatial genetic patterns or which seascape features were associated with these patterns. Furthermore, even in the absence of visually similar, or correlated spatial genetic patterns, our approach enabled us to identify seascape features that had a common influence on the spatial genetic patterns of co-distributed species.
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    Seascape Genetics: Populations, Individuals, and Genes Marooned and Adrift
    (1/03/2013) Riginos C; Liggins L
    Seascape genetics is the study of how spatially variable structural and environmental features influence genetic patterns of marine organisms. Seascape genetics is conceptually linked to landscape genetics and this likeness frequently allows investigators to use similar theoretical and analytical methods for both seascape genetics and landscape genetics. But, the physical and environmental attributes of the ocean and biological attributes of organisms that live in the sea, especially the large spatial scales of seascape features and the high dispersal ability of many marine organisms, differ from those of terrestrial organisms that have typified landscape genetic studies. This paper reviews notable papers in the emerging field of seascape genetics, highlighting pervasive themes and biological attributes of species and seascape features that affect spatial genetic patterns in the sea. Similarities to, and differences from, (terrestrial) landscape genetics are discussed, and future directions are recommended. © 2012 Blackwell Publishing Ltd.
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    Taking the Plunge: An Introduction to Undertaking Seascape Genetic Studies and using Biophysical Models
    (1/03/2013) Liggins L; Treml EA; Riginos C
    The field of seascape genetics aims to evaluate the effects of environmental features on spatial genetic patterns of marine organisms. Although many methods of genetic analysis and inference appropriate to "marine landscapes" derive from terrestrial landscape genetics, aspects of marine living introduce special challenges for assessing spatial genetic variation. For instance, marine organisms are often highly dispersive, so that genetic patterns can be subtle, and the temporal variability of the marine environment makes these patterns difficult to characterise. Tools and techniques from oceanography can help describe the highly connected and dynamic nature of the marine environment. In particular, models incorporating physical oceanography and species attributes in realistic simulations (e.g. biophysical models) can help us understand this complex process and formulate spatially explicit biologically-informed predictions of gene flow. Thus, researchers embarking on a seascape genetic study need a solid understanding of marine organisms and spatial genetics perhaps combined with knowledge of physical oceanography and ecological modeling. Although some researchers may acquire proficiency in all of these areas, seascape genetic studies incorporating biophysical modeling are likely to bring together groups of investigators with complementary expertise. This preliminary guide is intended to be a starting point for a reader new to either seascape genetics or biophysical models. © 2013 Blackwell Publishing Ltd.
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    Vicariance and dispersal across an intermittent barrier: Population genetic structure of marine animals across the Torres Strait land bridge
    (SPRINGER, 1/12/2011) Mirams AGK; Treml EA; Shields JL; Liggins L; Riginos C
    Biogeographic barriers, some transitory in duration, are likely to have been important contributing factors to modern marine biodiversity in the Indo-Pacific region. One such barrier was the Torres Strait land bridge between continental Australia and New Guinea that persisted through much of the late Pleistocene and separated Indian and Pacific Ocean taxa. Here, we examine the patterns of mitochondrial DNA diversity for marine animals with present-day distributions spanning the Torres Strait. Specifically, we investigate whether there are concordant signatures across species, consistent with either vicariance or recent colonization from either ocean basin. We survey four species of reef fishes (Apogon doederleini, Pomacentrus coelestis, Dascyllus trimaculatus, and Acanthurus triostegus) for mtDNA cytochrome oxidase 1 and control region variation and contrast these results to previous mtDNA studies in diverse marine animals with similar distributions. We find substantial genetic partitioning (estimated from F-statistics and coalescent approaches) between Indian and Pacific Ocean populations for many species, consistent with regional persistence through the late Pleistocene in both ocean basins. The species-specific estimates of genetic divergence, however, vary greatly and for reef fishes we estimate substantially different divergence times among species. It is likely that Indian and Pacific Ocean populations have been isolated for multiple glacial cycles for some species, whereas for other species genetic connections have been more recent. Regional estimates of genetic diversity and directionality of gene flow also vary among species. Thus, there is no apparent consistency among historical patterns across the Torres Strait for these co-distributed marine animals. © 2011 Springer-Verlag.