Browsing by Author "Crandall ED"

Now showing 1 - 7 of 7
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    A decade of seascape genetics: Contributions to basic and applied marine connectivity
    (28/07/2016) Selkoe KA; D'Aloia CC; Crandall ED; Iacchei M; Liggins L; Puritz JB; Von Der Heyden S; Toonen RJ
    Seascape genetics, a term coined in 2006, is a fast growing area of population genetics that draws on ecology, oceanography and geography to address challenges in basic understanding of marine connectivity and applications to management. We provide an accessible overview of the latest developments in seascape genetics that merge exciting new ideas from the field of marine population connectivity with statistical and technical advances in population genetics. After summarizing the historical context leading to the emergence of seascape genetics, we detail questions and methodological approaches that are evolving the discipline, highlight applications to conservation and management, and conclude with a summary of the field's transition to seascape genomics. From 100 seascape genetic studies, we assess trends in taxonomic and geographic coverage, sampling and statistical design, and dominant seascape drivers. Notably, temperature, oceanography and geography show equal prevalence of influence on spatial genetic patterns, and tests of over 20 other seascape factors suggest that a variety of forces impact connectivity at distinct spatio-temporal scales. A new level of rigor in statistical analysis is critical for disentangling multiple drivers and spurious effects. Coupled with GIS data and genomic scale sequencing methods, this rigor is taking seascape genetics beyond an initial focus on identifying correlations to hypothesis-driven insights into patterns and processes of population connectivity and adaptation. The latest studies are illuminating differences between demographic, functional and neutral genetic connectivity, and informing applications to marine reserve design, fisheries science and strategies to assess resilience to climate change and other anthropogenic impacts.
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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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    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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    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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    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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    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.