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Pinsky ML, Clark RD, Bos JT. Coral Reef Population Genomics in an Age of Global Change. Annu Rev Genet 2023; 57:87-115. [PMID: 37384733 DOI: 10.1146/annurev-genet-022123-102748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
Coral reefs are both exceptionally biodiverse and threatened by climate change and other human activities. Here, we review population genomic processes in coral reef taxa and their importance for understanding responses to global change. Many taxa on coral reefs are characterized by weak genetic drift, extensive gene flow, and strong selection from complex biotic and abiotic environments, which together present a fascinating test of microevolutionary theory. Selection, gene flow, and hybridization have played and will continue to play an important role in the adaptation or extinction of coral reef taxa in the face of rapid environmental change, but research remains exceptionally limited compared to the urgent needs. Critical areas for future investigation include understanding evolutionary potential and the mechanisms of local adaptation, developing historical baselines, and building greater research capacity in the countries where most reef diversity is concentrated.
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Affiliation(s)
- Malin L Pinsky
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, New Jersey, USA
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, USA;
| | - René D Clark
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, New Jersey, USA
| | - Jaelyn T Bos
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, New Jersey, USA
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2
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Alvarado-Cerón V, Muñiz-Castillo AI, León-Pech MG, Prada C, Arias-González JE. A decade of population genetics studies of scleractinian corals: A systematic review. MARINE ENVIRONMENTAL RESEARCH 2023; 183:105781. [PMID: 36371949 DOI: 10.1016/j.marenvres.2022.105781] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
Coral reefs are the most diverse marine ecosystems. However, coral cover has decreased worldwide due to natural disturbances, climate change, and local anthropogenic drivers. In recent decades, various genetic methods and molecular markers have been developed to assess genetic diversity, structure, and connectivity in different coral species to determine the vulnerability of their populations. This review aims to identify population genetic studies of scleractinian corals in the last decade (2010-2020), and the techniques and molecular markers used. Bibliometric analysis was conducted to identify journals and authors working in this field. We then calculated the number of genetic studies by species and ecoregion based on data obtained from 178 studies found in Scopus and Web of Science. Coral Reefs and Molecular Ecology were the main journals published population genetics studies, and microsatellites are the most widely used molecular markers. The Caribbean, Australian Barrier Reef, and South Kuroshio in Japan are among the ecoregions with the most population genetics data. In contrast, we found limited information about the Coral Triangle, a region with the highest biodiversity and key to coral reef conservation. Notably, only 117 (out of 1500 described) scleractinian coral species have genetic studies. This review emphasizes which coral species have been studied and highlights remaining gaps and locations where such data is critical for coral conservation.
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Affiliation(s)
- Viridiana Alvarado-Cerón
- Departamento de Recursos del Mar, Centro de Investigación y de Estudios Avanzados del I.P.N., Unidad Mérida. Km. 6 Antigua carretera a Progreso, Cordemex, 97310, Mérida, Yucatán, Mexico.
| | - Aarón Israel Muñiz-Castillo
- Departamento de Recursos del Mar, Centro de Investigación y de Estudios Avanzados del I.P.N., Unidad Mérida. Km. 6 Antigua carretera a Progreso, Cordemex, 97310, Mérida, Yucatán, Mexico.
| | - María Geovana León-Pech
- Department of Biological Science, University of Rhode Island, 120 Flag Road, Kingston, RI, 02881, USA.
| | - Carlos Prada
- Department of Biological Science, University of Rhode Island, 120 Flag Road, Kingston, RI, 02881, USA.
| | - Jesús Ernesto Arias-González
- Departamento de Recursos del Mar, Centro de Investigación y de Estudios Avanzados del I.P.N., Unidad Mérida. Km. 6 Antigua carretera a Progreso, Cordemex, 97310, Mérida, Yucatán, Mexico.
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3
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Tsuchiya K, Zayasu Y, Nakajima Y, Arakaki N, Suzuki G, Satoh N, Shinzato C. Genomic analysis of a reef-building coral, Acropora digitifera, reveals complex population structure and a migration network in the Nansei Islands, Japan. Mol Ecol 2022; 31:5270-5284. [PMID: 36082782 DOI: 10.1111/mec.16665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 06/04/2022] [Accepted: 08/08/2022] [Indexed: 12/15/2022]
Abstract
Understanding the structure and connectivity of coral populations is fundamental for developing marine conservation policies, especially in patchy environments such as archipelagos. The Nansei Islands, extending more than 1000 km in southwestern Japan, are characterized by high levels of biodiversity and endemism, supported by coral reefs, which make this region ideal for assessing genetic attributes of coral populations. In this study, we conducted population genomic analyses based on genome-wide, single-nucleotide polymorphisms (SNPs) of Acropora digitifera, a common species in the Nansei Islands. By merging newly obtained genome resequencing data with previously published data, we identified more than 4 million genome-wide SNPs in 303 colonies collected at 22 locations, with sequencing coverage ranging from 3.91× to 27.41×. While population structure analyses revealed genetic similarities between the southernmost and northernmost locations, separated by >1000 km, several subpopulations in intermediate locations suggested limited genetic admixture, indicating conflicting migration tendencies in the Nansei Islands. Although migration networks revealed a general tendency of northward migration along the Kuroshio Current, a substantial amount of southward migration was also detected, indicating important contributions of minor ocean currents to coral larval dispersal. Moreover, heterogeneity in the transition of effective population sizes among locations suggests different histories for individual subpopulations. The unexpected complexity of both past and present population dynamics in the Nansei Islands implies that heterogeneity of ocean currents and local environments, past and present, have influenced the population structure of this species, and similar unexpected population complexities may be expected for other marine species with similar reproductive modes.
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Affiliation(s)
- Kojin Tsuchiya
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
| | - Yuna Zayasu
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Japan
| | - Yuichi Nakajima
- Center for Climate Change Adaptation, National Institute for Environmental Studies, Tsukuba, Japan
| | - Nana Arakaki
- DNA Sequencing Section, Okinawa Institute of Science and Technology Graduate University, Onna, Japan
| | - Go Suzuki
- Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Ishigaki, Japan
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Japan
| | - Chuya Shinzato
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
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4
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Payet SD, Pratchett MS, Saenz‐Agudelo P, Berumen ML, DiBattista JD, Harrison HB. Demographic histories shape population genomics of the common coral grouper ( Plectropomus leopardus). Evol Appl 2022; 15:1221-1235. [PMID: 36051464 PMCID: PMC9423088 DOI: 10.1111/eva.13450] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 06/02/2022] [Accepted: 07/08/2022] [Indexed: 11/28/2022] Open
Abstract
Many coral reef fishes display remarkable genetic and phenotypic variation across their geographic ranges. Understanding how historical and contemporary processes have shaped these patterns remains a focal question in evolutionary biology since they reveal how diversity is generated and how it may respond to future environmental change. Here, we compare the population genomics and demographic histories of a commercially and ecologically important coral reef fish, the common coral grouper (Plectropomus leopardus [Lacépède 1802]), across two adjoining regions (the Great Barrier Reef; GBR, and the Coral Sea, Australia) spanning approximately 14 degrees of latitude and 9 degrees of longitude. We analysed 4548 single nucleotide polymorphism (SNP) markers across 11 sites and show that genetic connectivity between regions is low, despite their relative proximity (~100 km) and an absence of any obvious geographic barrier. Inferred demographic histories using 10,479 markers suggest that the Coral Sea population was founded by a small number of GBR individuals and that divergence occurred ~190 kya under a model of isolation with asymmetric migration. We detected population expansions in both regions, but estimates of contemporary effective population sizes were approximately 50% smaller in Coral Sea sites, which also had lower genetic diversity. Our results suggest that P. leopardus in the Coral Sea have experienced a long period of isolation that precedes the recent glacial period (~10-120 kya) and may be vulnerable to localized disturbances due to their relative reliance on local larval replenishment. While it is difficult to determine the underlying events that led to the divergence of the Coral Sea and GBR lineages, we show that even geographically proximate populations of a widely dispersed coral reef fish can have vastly different evolutionary histories.
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Affiliation(s)
- Samuel D. Payet
- Australian Research Council Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQueenslandAustralia
| | - Morgan S. Pratchett
- Australian Research Council Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQueenslandAustralia
| | - Pablo Saenz‐Agudelo
- Instituto de Ciencias Ambientales y EvolutivasUniversidad Austral de ChileValdiviaChile
| | - Michael L. Berumen
- Division of Biological and Environmental Science and Engineering, Red Sea Research CenterKing Abdullah University of Science and TechnologyThuwalSaudi Arabia
| | - Joseph D. DiBattista
- Australian Museum Research Institute, Australian MuseumSydneyNew South WalesAustralia
| | - Hugo B. Harrison
- Australian Research Council Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQueenslandAustralia
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
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5
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Li M, Huang W, Wu Q, Feng Y, Chen Y, Yu K, Chen B, Yang E, Meng L, Huang X, Wang X. High genetic differentiation and moderate genetic diversity of the degenerative branching coral Pocillopora verrucosa in the tropical South China Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 819:153076. [PMID: 35038534 DOI: 10.1016/j.scitotenv.2022.153076] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/08/2022] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
Global warming is causing rapid degradation of coral reefs, among which branching corals are degrading the fastest. An assessment of coral genetic diversity and adaptive potential provides a basis for coral reef protection. In this study, we selected the branching coral Pocillopora verrucosa, a widely distributed species in the tropical South China Sea (SCS), to carry out population genetic studies. To analyze the genetic diversity and structure of 319 P. verrucosa samples from 10 populations in 4 SCS regions, twelve pairs of microsatellite primers and two nuclear markers, ITS and β-tub, were selected. Microsatellite marker results showed moderate genetic diversity for P. verrucosa in the SCS, but relatively low diversity in Dazhou Island and Yongxing Island. The haplotype network showed that P. verrucosa in the SCS was derived from two ancestors, which may be linked to geographical isolation in the Pleistocene glacial period. AMOVA (ΦST = 0.3375) and FST pairwise analysis results based on β-tub showed that the populations were highly differentiated, with most FST values (21/45) > 0.25. Yongxing and Qilianyu Islands populations were significantly different from those in the Xisha area. Mantel test results showed that genetic differentiation among P. verrucosa populations was significantly and positively correlated with both mean sea surface temperature (SST) and SST variance, and was not correlated with distance, chlorophyll-a, or turbidity. The reproductive mode of brooding planulae was an important factor contributing to high genetic differentiation among populations. The moderate genetic diversity of SCS P. verrucosa indicates that this population has a certain genetic potential in the context of global changes, but the high genetic differentiation between populations increases the risk of local degradation or extinction. This study provides a theoretical basis for the protection and restoration of SCS coral reefs.
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Affiliation(s)
- Ming Li
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China; Forestry College, Guangxi University, Nanning 530004, China
| | - Wen Huang
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China.
| | - Qian Wu
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China
| | - Yi Feng
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China
| | - Yinmin Chen
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China
| | - Kefu Yu
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519080, China.
| | - Biao Chen
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China
| | - Enguang Yang
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China
| | - Linqing Meng
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China
| | - Xueyong Huang
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China
| | - Xin Wang
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China; Gunagxi Key Lab of Mangrove Conservation and Utilization, Guangxi Mangrove Research Center, Beihai 536000, China
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6
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Zheng SS, Jiang XL, Huang QJ, Deng M. Historical Dynamics of Semi-Humid Evergreen Forests in the Southeast Himalaya Biodiversity Hotspot: A Case Study of the Quercus franchetii Complex (Fagaceae). FRONTIERS IN PLANT SCIENCE 2021; 12:774232. [PMID: 35035389 PMCID: PMC8753985 DOI: 10.3389/fpls.2021.774232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 10/28/2021] [Indexed: 06/14/2023]
Abstract
The Oligocene and Miocene are key periods in the formation of the modern topography and flora of East Asian and Indo-China. However, it is unclear how geological and climatic factors contributed to the high endemism and species richness of this region. The Quercus franchetii complex is widespread in the southeast Himalaya fringe and northern Indo-China with a long evolutionary history. It provides a unique proxy for studying the diversity pattern of evergreen woody lineages in this region since the Oligocene. In this study, we combined chloroplast (cpDNA) sequences, nuclear microsatellite loci (nSSRs), and species distribution modeling (SDM) to investigate the impacts of geological events on genetic diversity of the Q. franchetii complex. The results showed that the initial cpDNA haplotype divergence was estimated to occur during the middle Oligocene (30.7 Ma), which might have been raised by the tectonic activity at this episode to the Miocene. The nSSR results revealed two major groups of populations, the central Yunnan-Guizhou plateau (YGP) group and the peripheral distribution group when K = 2, in responding to the rapid YGP uplift during the late Miocene, which restricted gene flow between the populations in core and marginal areas. SDM analysis indicated that the distribution ranges of the Q. franchetii complex expanded northwards after the last glacial maximum, but the core distribution range in YGP was stable. Our results showed that the divergence of Q. franchetii complex is rooted in the mid-Oligocene. The early geological events during the Oligocene, and the late Miocene may play key roles to restrict seed-mediated gene flow among regions, but the pollen-mediated gene flow was less impacted. The uplifts of the YGP and the climate since LGM subsequently boosted the divergence of the populations in core and marginal areas.
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Affiliation(s)
- Si-Si Zheng
- Shanghai Chenshan Botanical Garden, Shanghai, China
- School of Ecological Technique and Engineering, Shanghai Institute of Technology, Shanghai, China
| | - Xiao-Long Jiang
- The Laboratory of Forestry Genetics, Central South University of Forestry and Technology, Changsha, China
| | - Qing-Jun Huang
- School of Ecological Technique and Engineering, Shanghai Institute of Technology, Shanghai, China
| | - Min Deng
- School of Ecology and Environmental Science, Yunnan University, Kunming, China
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
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7
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Bray RA, Cutmore SC, Cribb TH. A paradigm for the recognition of cryptic trematode species in tropical Indo-west Pacific fishes: the problematic genus Preptetos (Trematoda: Lepocreadiidae). Int J Parasitol 2021; 52:169-203. [PMID: 34656610 DOI: 10.1016/j.ijpara.2021.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/19/2021] [Accepted: 08/22/2021] [Indexed: 11/30/2022]
Abstract
Molecular data have transformed approaches to trematode taxonomy by providing objective evidence for the delineation of species. However, although the data are objective, the interpretation of these data regarding species boundaries is subjective, especially when different markers conflict. Conserved markers can lead to an underestimation of richness and those used for finer species delineation have the capacity to inflate species recognition, perhaps unrealistically. Here we examine molecular and morphological evidence for species recognition in an especially confusing system, the lepocreadiid genus Preptetos Pritchard, 1960 in acanthuriform fishes of the tropical Indo-west Pacific. We consider species boundaries within this genus based on combined data (ITS2 and 28S rDNA; cox1 mtDNA and morphometrics) for substantial new collections. Delineation of species using only morphological data suggest fewer species than analysis of the sequence data; the latter suggests the presence of potential cryptic species and analysis of different markers suggests the presence of differing numbers of species. We conclude that an integrative interpretation creates the most satisfying taxonomic hypothesis. In the light of the new data, we have chosen and propose a model of trematode species recognition that demands reciprocal monophyly in the most discriminating available molecular marker plus distinction in morphology or host distribution. By invoking these criteria, we distinguish eight species in our new tropical Indo-west Pacific collections. Six of these are new (Preptetos allocaballeroi n. sp., Preptetos paracaballeroi n. sp., Preptetos pearsoni n. sp., Preptetos prudhoei n. sp., Preptetos quandamooka n. sp. and Preptetos zebravaranus n. sp.) and we continue to recognise Preptetos cannoni Barker, Bray & Cribb, 1993 and Preptetos laguncula Bray and Cribb, 1996. Notably; two of the new species, P. allocaballeroi n. sp. and P. paracaballeroi n. sp., are morphologically cryptic relative to each other. Our criteria lead us to recognise, as species, populations with unvarying morphology and similar host relationships but which may have a complex population structure over their range. In our view, this paradigm has the capacity to render tractable the interpretation of the species status of the huge trematode fauna of the tropical Indo-west Pacific.
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Affiliation(s)
- Rodney A Bray
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
| | - Scott C Cutmore
- The University of Queensland, School of Biological Sciences, St Lucia, Queensland 4072, Australia
| | - Thomas H Cribb
- The University of Queensland, School of Biological Sciences, St Lucia, Queensland 4072, Australia
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8
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Morphological stasis masks ecologically divergent coral species on tropical reefs. Curr Biol 2021; 31:2286-2298.e8. [PMID: 33811819 DOI: 10.1016/j.cub.2021.03.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 02/13/2021] [Accepted: 03/09/2021] [Indexed: 01/07/2023]
Abstract
Coral reefs are the epitome of species diversity, yet the number of described scleractinian coral species, the framework-builders of coral reefs, remains moderate by comparison. DNA sequencing studies are rapidly challenging this notion by exposing a wealth of undescribed diversity, but the evolutionary and ecological significance of this diversity remains largely unclear. Here, we present an annotated genome for one of the most ubiquitous corals in the Indo-Pacific (Pachyseris speciosa) and uncover, through a comprehensive genomic and phenotypic assessment, that it comprises morphologically indistinguishable but ecologically divergent lineages. Demographic modeling based on whole-genome resequencing indicated that morphological crypsis (across micro- and macromorphological traits) was due to ancient morphological stasis rather than recent divergence. Although the lineages occur sympatrically across shallow and mesophotic habitats, extensive genotyping using a rapid molecular assay revealed differentiation of their ecological distributions. Leveraging "common garden" conditions facilitated by the overlapping distributions, we assessed physiological and quantitative skeletal traits and demonstrated concurrent phenotypic differentiation. Lastly, spawning observations of genotyped colonies highlighted the potential role of temporal reproductive isolation in the limited admixture, with consistent genomic signatures in genes related to morphogenesis and reproduction. Overall, our findings demonstrate the presence of ecologically and phenotypically divergent coral species without substantial morphological differentiation and provide new leads into the potential mechanisms facilitating such divergence. More broadly, they indicate that our current taxonomic framework for reef-building corals may be scratching the surface of the ecologically relevant diversity on coral reefs, consequently limiting our ability to protect or restore this diversity effectively.
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9
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Hall TE, Freedman AS, de Roos AM, Edmunds PJ, Carpenter RC, Gross K. Stony coral populations are more sensitive to changes in vital rates in disturbed environments. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02234. [PMID: 33064870 DOI: 10.1002/eap.2234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/10/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
Reef-building corals, like many long-lived organisms, experience environmental change as a combination of separate but concurrent processes, some of which are gradual yet long-lasting, while others are more acute but short-lived. For corals, some chronic environmental stressors, such as rising temperature and ocean acidification, are thought to induce gradual changes in colonies' vital rates. Meanwhile, other environmental changes, such as the intensification of tropical cyclones, change the disturbance regime that corals experience. Here, we use a physiologically structured population model to explore how chronic environmental stressors that impact the vital rates of individual coral colonies interact with the intensity and magnitude of disturbance to affect coral population dynamics and cover. We find that, when disturbances are relatively benign, intraspecific density dependence driven by space competition partially buffers coral populations against gradual changes in vital rates. However, the impact of chronic stressors is amplified in more highly disturbed environments, because disturbance weakens the buffering effect of space competition. We also show that coral cover is more sensitive to changes in colony growth and mortality than to external recruitment, at least in open populations, and that space competition and size structure mediate the extent and pace of coral population recovery following a large-scale mortality event. Understanding the complex interplay among chronic environmental stressors, mass-mortality events, and population size structure sharpens our ability to manage and to restore coral-reef ecosystems in an increasingly disturbed future.
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Affiliation(s)
- Tessa E Hall
- Biomathematics Program, North Carolina State University, Raleigh, North Carolina, 27695, USA
| | - Andrew S Freedman
- Biomathematics Program, North Carolina State University, Raleigh, North Carolina, 27695, USA
| | - André M de Roos
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
- Santa Fe Institute, Santa Fe, New Mexico, 87501, USA
| | - Peter J Edmunds
- Department of Biology, California State University, Northridge, California, 91330, USA
| | - Robert C Carpenter
- Department of Biology, California State University, Northridge, California, 91330, USA
| | - Kevin Gross
- Biomathematics Program, North Carolina State University, Raleigh, North Carolina, 27695, USA
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10
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Davies SW, Moreland KN, Wham DC, Kanke MR, Matz MV. Cladocopium community divergence in two Acropora coral hosts across multiple spatial scales. Mol Ecol 2020; 29:4559-4572. [PMID: 33002237 DOI: 10.1111/mec.15668] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 09/14/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022]
Abstract
Many broadly-dispersing corals acquire their algal symbionts (Symbiodiniaceae) "horizontally" from their environment upon recruitment. Horizontal transmission could promote coral fitness across diverse environments provided that corals can associate with divergent algae across their range and that these symbionts exhibit reduced dispersal potential. Here we quantified community divergence of Cladocopium algal symbionts in two coral host species (Acropora hyacinthus, Acropora digitifera) across two spatial scales (reefs on the same island, and between islands) across the Micronesian archipelago using microsatellites. We find that both hosts associated with a variety of multilocus genotypes (MLG) within two genetically distinct Cladocopium lineages (C40, C21), confirming that Acropora coral hosts associate with a range of Cladocopium symbionts across this region. Both C40 and C21 included multiple asexual lineages bearing identical MLGs, many of which spanned host species, reef sites within islands, and even different islands. Both C40 and C21 exhibited moderate host specialization and divergence across islands. In addition, within every island, algal symbiont communities were significantly clustered by both host species and reef site, highlighting that coral-associated Cladocopium communities are structured across small spatial scales and within hosts on the same reef. This is in stark contrast to their coral hosts, which never exhibited significant genetic divergence between reefs on the same island. These results support the view that horizontal transmission could improve local fitness for broadly dispersing Acropora coral species.
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Affiliation(s)
- Sarah W Davies
- Department of Biology, Boston University, Boston, MA, USA.,Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA
| | - Kelsey N Moreland
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA
| | - Drew C Wham
- Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Matt R Kanke
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Mikhail V Matz
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA
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11
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Fuller ZL, Mocellin VJL, Morris LA, Cantin N, Shepherd J, Sarre L, Peng J, Liao Y, Pickrell J, Andolfatto P, Matz M, Bay LK, Przeworski M. Population genetics of the coral Acropora millepora: Toward genomic prediction of bleaching. Science 2020; 369:369/6501/eaba4674. [PMID: 32675347 DOI: 10.1126/science.aba4674] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 06/01/2020] [Indexed: 12/11/2022]
Abstract
Although reef-building corals are declining worldwide, responses to bleaching vary within and across species and are partly heritable. Toward predicting bleaching response from genomic data, we generated a chromosome-scale genome assembly for the coral Acropora millepora We obtained whole-genome sequences for 237 phenotyped samples collected at 12 reefs along the Great Barrier Reef, among which we inferred little population structure. Scanning the genome for evidence of local adaptation, we detected signatures of long-term balancing selection in the heat-shock co-chaperone sacsin We conducted a genome-wide association study of visual bleaching score for 213 samples, incorporating the polygenic score derived from it into a predictive model for bleaching in the wild. These results set the stage for genomics-based approaches in conservation strategies.
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Affiliation(s)
- Zachary L Fuller
- Department of Biological Sciences, Columbia University, New York, NY, USA.
| | | | - Luke A Morris
- Australian Institute of Marine Science, Townsville, QLD, Australia.,AIMS@JCU, Australian Institute of Marine Science, College of Science and Engineering, James Cook University, Townsville, QLD, Australia.,College of Science and Engineering, James Cook University, Townsville, QLD, Australia
| | - Neal Cantin
- Australian Institute of Marine Science, Townsville, QLD, Australia
| | - Jihanne Shepherd
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Luke Sarre
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Julie Peng
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Yi Liao
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.,Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA, USA
| | | | - Peter Andolfatto
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Mikhail Matz
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Line K Bay
- Australian Institute of Marine Science, Townsville, QLD, Australia.
| | - Molly Przeworski
- Department of Biological Sciences, Columbia University, New York, NY, USA. .,Department of Systems Biology, Columbia University, New York, NY, USA.,Program for Mathematical Genomics, Columbia University, New York, NY, USA
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12
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Cornwell BH. Gene flow in the anemone
Anthopleura elegantissima
limits signatures of local adaptation across an extensive geographic range. Mol Ecol 2020; 29:2550-2566. [DOI: 10.1111/mec.15506] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 05/22/2020] [Accepted: 06/01/2020] [Indexed: 02/06/2023]
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13
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Quigley KM, Bay LK, van Oppen MJH. The active spread of adaptive variation for reef resilience. Ecol Evol 2019; 9:11122-11135. [PMID: 31641460 PMCID: PMC6802068 DOI: 10.1002/ece3.5616] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/03/2019] [Accepted: 08/06/2019] [Indexed: 12/26/2022] Open
Abstract
The speed at which species adapt depends partly on the rates of beneficial adaptation generation and how quickly they spread within and among populations. Natural rates of adaptation of corals may not be able to keep pace with climate warming. Several interventions have been proposed to fast-track thermal adaptation, including the intentional translocation of warm-adapted adults or their offspring (assisted gene flow, AGF) and the ex situ crossing of warm-adapted corals with conspecifics from cooler reefs (hybridization or selective breeding) and field deployment of those offspring. The introgression of temperature tolerance loci into the genomic background of cooler-environment corals aims to facilitate adaptation to warming while maintaining fitness under local conditions. Here we use research on selective sweeps and connectivity to understand the spread of adaptive variants as it applies to AGF on the Great Barrier Reef (GBR), focusing on the genus Acropora. Using larval biophysical dispersal modeling, we estimate levels of natural connectivity in warm-adapted northern corals. We then model the spread of adaptive variants from single and multiple reefs and assess if the natural and assisted spread of adaptive variants will occur fast enough to prepare receiving central and southern populations given current rates of warming. We also estimate fixation rates and spatial extent of fixation under multiple release scenarios to inform intervention design. Our results suggest that thermal tolerance is unlikely to spread beyond northern reefs to the central and southern GBR without intervention, and if it does, 30+ generations are needed for adaptive gene variants to reach fixation even under multiple release scenarios. We argue that if translocation, breeding, and reseeding risks are managed, AGF using multiple release reefs can be beneficial for the restoration of coral populations. These interventions should be considered in addition to conventional management and accompanied by strong mitigation of CO2 emissions.
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Affiliation(s)
- Kate M. Quigley
- Australian Institute of Marine ScienceTownsvilleQldAustralia
| | - Line K. Bay
- Australian Institute of Marine ScienceTownsvilleQldAustralia
| | - Madeleine J. H. van Oppen
- Australian Institute of Marine ScienceTownsvilleQldAustralia
- School of BioSciencesThe University of MelbourneParkvilleVic.Australia
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14
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Riginos C, Hock K, Matias AM, Mumby PJ, Oppen MJH, Lukoschek V. Asymmetric dispersal is a critical element of concordance between biophysical dispersal models and spatial genetic structure in Great Barrier Reef corals. DIVERS DISTRIB 2019. [DOI: 10.1111/ddi.12969] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Cynthia Riginos
- School of Biological Sciences The University of Queensland St Lucia Queensland Australia
| | - Karlo Hock
- School of Biological Sciences The University of Queensland St Lucia Queensland Australia
| | - Ambrocio M. Matias
- School of Biological Sciences The University of Queensland St Lucia Queensland Australia
- Institute of Biology University of the Philippines Diliman Quezon City Philippines
| | - Peter J. Mumby
- School of Biological Sciences The University of Queensland St Lucia Queensland Australia
| | - Madeleine J. H. Oppen
- Institute of Biology University of the Philippines Diliman Quezon City Philippines
- School of BioSciences The University of Melbourne Parkville Victoria Australia
- Australian Institute for Marine Sciences Cape Cleveland Queensland Australia
| | - Vimoksalehi Lukoschek
- ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville Queensland Australia
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15
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Marcaccioli R, Livan G. A Pólya urn approach to information filtering in complex networks. Nat Commun 2019; 10:745. [PMID: 30765706 PMCID: PMC6375975 DOI: 10.1038/s41467-019-08667-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 01/23/2019] [Indexed: 11/18/2022] Open
Abstract
The increasing availability of data demands for techniques to filter information in large complex networks of interactions. A number of approaches have been proposed to extract network backbones by assessing the statistical significance of links against null hypotheses of random interaction. Yet, it is well known that the growth of most real-world networks is non-random, as past interactions between nodes typically increase the likelihood of further interaction. Here, we propose a filtering methodology inspired by the Pólya urn, a combinatorial model driven by a self-reinforcement mechanism, which relies on a family of null hypotheses that can be calibrated to assess which links are statistically significant with respect to a given network's own heterogeneity. We provide a full characterization of the filter, and show that it selects links based on a non-trivial interplay between their local importance and the importance of the nodes they belong to.
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Affiliation(s)
- Riccardo Marcaccioli
- Department of Computer Science, University College London, 66-72 Gower Street, London, WC1E 6EA, UK
| | - Giacomo Livan
- Department of Computer Science, University College London, 66-72 Gower Street, London, WC1E 6EA, UK.
- Systemic Risk Centre, London School of Economics and Political Sciences, Houghton Street, London, WC2A 2AE, UK.
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16
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Role of gene body methylation in acclimatization and adaptation in a basal metazoan. Proc Natl Acad Sci U S A 2018; 115:13342-13346. [PMID: 30530646 DOI: 10.1073/pnas.1813749115] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Gene body methylation (GBM) has been hypothesized to modulate responses to environmental change, including transgenerational plasticity, but the evidence thus far has been lacking. Here we show that coral fragments reciprocally transplanted between two distant reefs respond predominantly by increase or decrease in genome-wide GBM disparity: The range of methylation levels between lowly and highly methylated genes becomes either wider or narrower. Remarkably, at a broad functional level this simple adjustment correlated very well with gene expression change, reflecting a shifting balance between expressions of environmentally responsive and housekeeping genes. In our experiment, corals in a lower-quality habitat up-regulated genes involved in environmental responses, while corals in a higher-quality habitat invested more in housekeeping genes. Transplanted fragments showing closer GBM match to local corals attained higher fitness characteristics, which supports GBM's role in acclimatization. Fixed differences in GBM between populations did not align with plastic GBM changes and were mostly observed in genes with elevated F ST, which suggests that they arose predominantly through genetic divergence. However, we cannot completely rule out transgenerational inheritance of acquired GBM states.
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17
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van Oppen MJH, Bongaerts P, Frade P, Peplow L, Boyd SE, Nim HT, Bay LK. Adaptation to reef habitats through selection on the coral animal and its associated microbiome. Mol Ecol 2018; 27:2956-2971. [DOI: 10.1111/mec.14763] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 06/01/2018] [Accepted: 06/04/2018] [Indexed: 01/02/2023]
Affiliation(s)
- Madeleine J. H. van Oppen
- Australian Institute of Marine Science; Townsville MC Qld Australia
- School of BioSciences; University of Melbourne; Parkville Vic. Australia
| | - Pim Bongaerts
- Global Change Institute; The University of Queensland; St Lucia Qld Australia
- California Academy of Sciences; San Francisco California
| | - Pedro Frade
- Centre of Marine Sciences (CCMAR); University of Algarve; Faro Portugal
| | - Lesa M. Peplow
- Australian Institute of Marine Science; Townsville MC Qld Australia
| | - Sarah E. Boyd
- Faculty of Information Technology; Monash University; Melbourne Vic. Australia
| | - Hieu T. Nim
- Faculty of Information Technology; Monash University; Melbourne Vic. Australia
- Australian Regenerative Medicine Institute; Monash University; Melbourne Vic. Australia
| | - Line K. Bay
- Australian Institute of Marine Science; Townsville MC Qld Australia
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18
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Matz MV, Treml EA, Aglyamova GV, Bay LK. Potential and limits for rapid genetic adaptation to warming in a Great Barrier Reef coral. PLoS Genet 2018; 14:e1007220. [PMID: 29672529 PMCID: PMC5908067 DOI: 10.1371/journal.pgen.1007220] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 01/24/2018] [Indexed: 01/03/2023] Open
Abstract
Can genetic adaptation in reef-building corals keep pace with the current rate of sea surface warming? Here we combine population genomics, biophysical modeling, and evolutionary simulations to predict future adaptation of the common coral Acropora millepora on the Great Barrier Reef (GBR). Genomics-derived migration rates were high (0.1–1% of immigrants per generation across half the latitudinal range of the GBR) and closely matched the biophysical model of larval dispersal. Both genetic and biophysical models indicated the prevalence of southward migration along the GBR that would facilitate the spread of heat-tolerant alleles to higher latitudes as the climate warms. We developed an individual-based metapopulation model of polygenic adaptation and parameterized it with population sizes and migration rates derived from the genomic analysis. We find that high migration rates do not disrupt local thermal adaptation, and that the resulting standing genetic variation should be sufficient to fuel rapid region-wide adaptation of A. millepora populations to gradual warming over the next 20–50 coral generations (100–250 years). Further adaptation based on novel mutations might also be possible, but this depends on the currently unknown genetic parameters underlying coral thermal tolerance and the rate of warming realized. Despite this capacity for adaptation, our model predicts that coral populations would become increasingly sensitive to random thermal fluctuations such as ENSO cycles or heat waves, which corresponds well with the recent increase in frequency of catastrophic coral bleaching events. Coral reefs worldwide are suffering high mortality from severe thermal stress episodes induced by acute ocean warming events. Under the current rate of warming, will corals be gone before the end of this century? Here we combine population genomics with biophysical and evolutionary modeling to investigate adaptive potential of a common reef-building coral from the Great Barrier Reef. To approach this task, we have developed a predictive model of polygenic adaptation in a system of multiple inter-connected populations that exist in a heterogeneous and changing environment. Applying this model to our coral species, we find that populations successfully adapt to diverse local temperatures along the range of the Great Barrier Reef despite high migrant exchange and should collectively harbor enough adaptive genetic variants to fuel region-wide thermal adaptation for another century and perhaps longer. In the same time, the model predicts that random thermal fluctuations will induce increasingly severe coral mortality episodes, which aligns well with observations over the last few decades.
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Affiliation(s)
- Mikhail V. Matz
- University of Texas at Austin, Austin, Texas, United States of America
- * E-mail:
| | - Eric A. Treml
- University of Melbourne, Melbourne, Melbourne, Victoria, Australia
| | | | - Line K. Bay
- Australian Institute of Marine Science, Townsville, Queensland, Australia
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19
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Marine Refugia Past, Present, and Future: Lessons from Ancient Geologic Crises for Modern Marine Ecosystem Conservation. ACTA ACUST UNITED AC 2018. [DOI: 10.1007/978-3-319-73795-9_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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20
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Contemporary and historical oceanographic processes explain genetic connectivity in a Southwestern Atlantic coral. Sci Rep 2018; 8:2684. [PMID: 29422662 PMCID: PMC5805724 DOI: 10.1038/s41598-018-21010-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 01/05/2018] [Indexed: 11/09/2022] Open
Abstract
Understanding connectivity patterns has implications for evolutionary and ecological processes, as well as for proper conservation strategies. This study examined population genetic structure and migration patterns of the coral Mussismilia hispida, one of the main reef builders in the Southwestern Atlantic Ocean. For this, 15 sites were sampled along its entire distributional range employing 10 microsatellite loci. M. hispida was divided into five genetically differentiated populations by Structure analysis. Population structure and migration estimates are consistent with present-day oceanographic current patterns, zones of upwelling and historical sea-level changes. The Central Region and Oceanic Islands populations had the highest genetic diversity, were possibly the main sources of migrants for other populations and presented mutual migrant exchange. This mutual exchange and the high diversity of Oceanic Islands, a peripherical population, is highly interesting and unexpected, but can be explained if these sites acted as refugia in past low sea-level stance. This is the first connectivity study in the region using hyper-variable markers and a fine sampling scale along 3,500 km. These results enlighten the population dynamics of an important reef building species and shows how oceanographic processes may act as barriers to dispersal for marine species, providing valuable information for management strategies.
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21
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van Oppen MJH, Gates RD, Blackall LL, Cantin N, Chakravarti LJ, Chan WY, Cormick C, Crean A, Damjanovic K, Epstein H, Harrison PL, Jones TA, Miller M, Pears RJ, Peplow LM, Raftos DA, Schaffelke B, Stewart K, Torda G, Wachenfeld D, Weeks AR, Putnam HM. Shifting paradigms in restoration of the world's coral reefs. GLOBAL CHANGE BIOLOGY 2017; 23:3437-3448. [PMID: 28247459 DOI: 10.1111/gcb.13647] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 05/18/2023]
Abstract
Many ecosystems around the world are rapidly deteriorating due to both local and global pressures, and perhaps none so precipitously as coral reefs. Management of coral reefs through maintenance (e.g., marine-protected areas, catchment management to improve water quality), restoration, as well as global and national governmental agreements to reduce greenhouse gas emissions (e.g., the 2015 Paris Agreement) is critical for the persistence of coral reefs. Despite these initiatives, the health and abundance of corals reefs are rapidly declining and other solutions will soon be required. We have recently discussed options for using assisted evolution (i.e., selective breeding, assisted gene flow, conditioning or epigenetic programming, and the manipulation of the coral microbiome) as a means to enhance environmental stress tolerance of corals and the success of coral reef restoration efforts. The 2014-2016 global coral bleaching event has sharpened the focus on such interventionist approaches. We highlight the necessity for consideration of alternative (e.g., hybrid) ecosystem states, discuss traits of resilient corals and coral reef ecosystems, and propose a decision tree for incorporating assisted evolution into restoration initiatives to enhance climate resilience of coral reefs.
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Affiliation(s)
- Madeleine J H van Oppen
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, QLD, 4810, Australia
- School of BioSciences, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Ruth D Gates
- Hawaii Institute of Marine Biology, Kaneohe, HI, 96744, USA
| | - Linda L Blackall
- School of BioSciences, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Neal Cantin
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, QLD, 4810, Australia
| | - Leela J Chakravarti
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, QLD, 4810, Australia
- AIMS@JCU, James Cook University, Townsville, QLD, 4811, Australia
- College of Marine and Environmental Sciences, James Cook University, Townsville, QLD, 4811, Australia
| | - Wing Y Chan
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, QLD, 4810, Australia
- School of BioSciences, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Craig Cormick
- ThinkOutsideThe, 12 Giffen Close, Holt, ACT, 2615, Australia
| | - Angela Crean
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Katarina Damjanovic
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, QLD, 4810, Australia
- School of BioSciences, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Hannah Epstein
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, QLD, 4810, Australia
- AIMS@JCU, James Cook University, Townsville, QLD, 4811, Australia
- College of Marine and Environmental Sciences, James Cook University, Townsville, QLD, 4811, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia
| | - Peter L Harrison
- Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, Australia
| | - Thomas A Jones
- USDA-Agricultural Research Service, Forage and Range Research Laboratory, Logan, UT, 84322-6300, USA
| | - Margaret Miller
- National Oceanic and Atmospheric Administration-National Marine Fisheries Service, Miami, FL, USA
| | - Rachel J Pears
- Great Barrier Reef Marine Park Authority, PO Box 1379, Townsville, QLD, 4810, Australia
| | - Lesa M Peplow
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, QLD, 4810, Australia
| | - David A Raftos
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Britta Schaffelke
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, QLD, 4810, Australia
| | - Kristen Stewart
- SUNY College of Environmental Science and Forestry, Syracuse, NY, 13210-2788, USA
| | - Gergely Torda
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, QLD, 4810, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia
| | - David Wachenfeld
- Great Barrier Reef Marine Park Authority, PO Box 1379, Townsville, QLD, 4810, Australia
| | - Andrew R Weeks
- School of BioSciences, University of Melbourne, Parkville, VIC, 3010, Australia
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22
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Gélin P, Fauvelot C, Mehn V, Bureau S, Rouzé H, Magalon H. Superclone Expansion, Long-Distance Clonal Dispersal and Local Genetic Structuring in the Coral Pocillopora damicornis Type β in Reunion Island, South Western Indian Ocean. PLoS One 2017; 12:e0169692. [PMID: 28068406 PMCID: PMC5222339 DOI: 10.1371/journal.pone.0169692] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 12/19/2016] [Indexed: 11/18/2022] Open
Abstract
The scleractinian coral Pocillopora damicornis type β is known to present a mixed reproduction mode: through sexual reproduction, new genotypes are created, while asexual reproduction insures their propagation. In order to investigate the relative proportion of each reproduction mode in P. damicornis type β populations from Reunion Island, Indian Ocean, clonal propagation along the west coast was assessed through four sampling sites with increasing geographical distance between sites. Coral colonies were sampled either exhaustively, randomly or haphazardly within each site, and genotypic diversity was assessed using 13 microsatellite loci over a total of 510 P. damicornis type β determined a posteriori from their mtDNA haplotype (a 840 bp sequenced fragment of the Open Reading Frame). Overall, 47% of all the sampled colonies presented the same multi-locus genotype (MLG), a superclone, suggesting that asexual propagation is extremely important in Reunion Island. Within each site, numerous MLGs were shared by several colonies, suggesting local clonal propagation through fragmentation. Moreover, some of these MLGs were found to be shared among several sites located 40 km apart. While asexual reproduction by fragmentation seems unlikely over long distances, our results suggest a production of parthenogenetic larvae. Despite shared MLGs, two differentiated clusters were enclosed among populations of the west coast of Reunion Island, revealing the necessity to set up appropriate managing strategies at a local scale.
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Affiliation(s)
- Pauline Gélin
- UMR ENTROPIE (IRD, Université de La Réunion, CNRS), Laboratoire d’excellence-CORAIL, Université de La Réunion, St Denis, La Réunion
- * E-mail:
| | - Cécile Fauvelot
- UMR ENTROPIE (IRD, Université de La Réunion, CNRS), Laboratoire d’excellence-CORAIL, centre IRD de Nouméa, New Caledonia
| | - Vincent Mehn
- UMR ENTROPIE (IRD, Université de La Réunion, CNRS), Laboratoire d’excellence-CORAIL, Université de La Réunion, St Denis, La Réunion
| | - Sophie Bureau
- UMR ENTROPIE (IRD, Université de La Réunion, CNRS), Laboratoire d’excellence-CORAIL, Université de La Réunion, St Denis, La Réunion
| | - Héloïse Rouzé
- UMR ENTROPIE (IRD, Université de La Réunion, CNRS), Laboratoire d’excellence-CORAIL, centre IRD de Nouméa, New Caledonia
| | - Hélène Magalon
- UMR ENTROPIE (IRD, Université de La Réunion, CNRS), Laboratoire d’excellence-CORAIL, Université de La Réunion, St Denis, La Réunion
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23
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Quigley KM, Willis BL, Bay LK. Maternal effects and Symbiodinium community composition drive differential patterns in juvenile survival in the coral Acropora tenuis. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160471. [PMID: 27853562 PMCID: PMC5098987 DOI: 10.1098/rsos.160471] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 09/12/2016] [Indexed: 05/24/2023]
Abstract
Coral endosymbionts in the dinoflagellate genus Symbiodinium are known to impact host physiology and have led to the evolution of reef-building, but less is known about how symbiotic communities in early life-history stages and their interactions with host parental identity shape the structure of coral communities on reefs. Differentiating the roles of environmental and biological factors driving variation in population demographic processes, particularly larval settlement, early juvenile survival and the onset of symbiosis is key to understanding how coral communities are structured and to predicting how they are likely to respond to climate change. We show that maternal effects (that here include genetic and/or effects related to the maternal environment) can explain nearly 24% of variation in larval settlement success and 5-17% of variation in juvenile survival in an experimental study of the reef-building scleractinian coral, Acropora tenuis. After 25 days on the reef, Symbiodinium communities associated with juvenile corals differed significantly between high mortality and low mortality families based on estimates of taxonomic richness, composition and relative abundance of taxa. Our results highlight that maternal and familial effects significantly explain variation in juvenile survival and symbiont communities in a broadcast-spawning coral, with Symbiodinium type A3 possibly a critical symbiotic partner during this early life stage.
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Affiliation(s)
- Kate M. Quigley
- College of Marine and Environmental Sciences, and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
- AIMS@JCU, Australian Institute of Marine Science and James Cook University, Townsville, Queensland 4811, Australia
| | - Bette L. Willis
- College of Marine and Environmental Sciences, and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
- AIMS@JCU, Australian Institute of Marine Science and James Cook University, Townsville, Queensland 4811, Australia
| | - Line K. Bay
- AIMS@JCU, Australian Institute of Marine Science and James Cook University, Townsville, Queensland 4811, Australia
- Australian Institute of Marine Science, PMB 3, Townsville, Queensland 4810, Australia
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24
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Quigley KM, Willis BL, Bay LK. Maternal effects and Symbiodinium community composition drive differential patterns in juvenile survival in the coral Acropora tenuis. ROYAL SOCIETY OPEN SCIENCE 2016. [PMID: 27853562 DOI: 10.5061/dryad.8b5g6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Coral endosymbionts in the dinoflagellate genus Symbiodinium are known to impact host physiology and have led to the evolution of reef-building, but less is known about how symbiotic communities in early life-history stages and their interactions with host parental identity shape the structure of coral communities on reefs. Differentiating the roles of environmental and biological factors driving variation in population demographic processes, particularly larval settlement, early juvenile survival and the onset of symbiosis is key to understanding how coral communities are structured and to predicting how they are likely to respond to climate change. We show that maternal effects (that here include genetic and/or effects related to the maternal environment) can explain nearly 24% of variation in larval settlement success and 5-17% of variation in juvenile survival in an experimental study of the reef-building scleractinian coral, Acropora tenuis. After 25 days on the reef, Symbiodinium communities associated with juvenile corals differed significantly between high mortality and low mortality families based on estimates of taxonomic richness, composition and relative abundance of taxa. Our results highlight that maternal and familial effects significantly explain variation in juvenile survival and symbiont communities in a broadcast-spawning coral, with Symbiodinium type A3 possibly a critical symbiotic partner during this early life stage.
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Affiliation(s)
- Kate M Quigley
- College of Marine and Environmental Sciences, and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia; AIMS@JCU, Australian Institute of Marine Science and James Cook University, Townsville, Queensland 4811, Australia
| | - Bette L Willis
- College of Marine and Environmental Sciences, and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia; AIMS@JCU, Australian Institute of Marine Science and James Cook University, Townsville, Queensland 4811, Australia
| | - Line K Bay
- AIMS@JCU, Australian Institute of Marine Science and James Cook University, Townsville, Queensland 4811, Australia; Australian Institute of Marine Science, PMB 3, Townsville, Queensland 4810, Australia
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25
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Lukoschek V, Riginos C, van Oppen MJH. Congruent patterns of connectivity can inform management for broadcast spawning corals on the Great Barrier Reef. Mol Ecol 2016; 25:3065-80. [DOI: 10.1111/mec.13649] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/18/2016] [Accepted: 04/12/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Vimoksalehi Lukoschek
- ARC Centre of Excellence for Coral Reef Studies; James Cook University; Townsville Qld 4811 Australia
| | - Cynthia Riginos
- School of Biological Sciences; The University of Queensland; St. Lucia Qld 4072 Australia
| | - Madeleine J. H. van Oppen
- ARC Centre of Excellence for Coral Reef Studies; James Cook University; Townsville Qld 4811 Australia
- Australian Institute of Marine Science; PMB 3; Townsville Mail Centre; Townsville Qld 4810 Australia
- School of BioSciences; The University of Melbourne; Parkville Vic. 3010 Australia
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Jin YK, Lundgren P, Lutz A, Raina JB, Howells EJ, Paley AS, Willis BL, van Oppen MJH. Genetic markers for antioxidant capacity in a reef-building coral. SCIENCE ADVANCES 2016; 2:e1500842. [PMID: 27386515 PMCID: PMC4928996 DOI: 10.1126/sciadv.1500842] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 04/20/2016] [Indexed: 05/02/2023]
Abstract
The current lack of understanding of the genetic basis underlying environmental stress tolerance in reef-building corals impairs the development of new management approaches to confronting the global demise of coral reefs. On the Great Barrier Reef (GBR), an approximately 51% decline in coral cover occurred over the period 1985-2012. We conducted a gene-by-environment association analysis across 12° latitude on the GBR, as well as both in situ and laboratory genotype-by-phenotype association analyses. These analyses allowed us to identify alleles at two genetic loci that account for differences in environmental stress tolerance and antioxidant capacity in the common coral Acropora millepora. The effect size for antioxidant capacity was considerable and biologically relevant (32.5 and 14.6% for the two loci). Antioxidant capacity is a critical component of stress tolerance because a multitude of environmental stressors cause increased cellular levels of reactive oxygen species. Our findings provide the first step toward the development of novel coral reef management approaches, such as spatial mapping of stress tolerance for use in marine protected area design, identification of stress-tolerant colonies for assisted migration, and marker-assisted selective breeding to create more tolerant genotypes for restoration of denuded reefs.
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Affiliation(s)
- Young K. Jin
- Australian Institute of Marine Science (AIMS), PMB No. 3, Townsville, Queensland 4810, Australia
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
- AIMS@JCU, James Cook University, Townsville, Queensland 4811, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - Petra Lundgren
- Australian Institute of Marine Science (AIMS), PMB No. 3, Townsville, Queensland 4810, Australia
- Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Adrian Lutz
- Australian Institute of Marine Science (AIMS), PMB No. 3, Townsville, Queensland 4810, Australia
- AIMS@JCU, James Cook University, Townsville, Queensland 4811, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
- School of BioSciences, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Jean-Baptiste Raina
- Australian Institute of Marine Science (AIMS), PMB No. 3, Townsville, Queensland 4810, Australia
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
- AIMS@JCU, James Cook University, Townsville, Queensland 4811, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
- Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Emily J. Howells
- Australian Institute of Marine Science (AIMS), PMB No. 3, Townsville, Queensland 4810, Australia
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
- AIMS@JCU, James Cook University, Townsville, Queensland 4811, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
- Center for Genomics and Systems Biology, New York University Abu Dhabi, United Arab Emirates
| | - Allison S. Paley
- Australian Institute of Marine Science (AIMS), PMB No. 3, Townsville, Queensland 4810, Australia
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
- AIMS@JCU, James Cook University, Townsville, Queensland 4811, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - Bette L. Willis
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
- AIMS@JCU, James Cook University, Townsville, Queensland 4811, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - Madeleine J. H. van Oppen
- Australian Institute of Marine Science (AIMS), PMB No. 3, Townsville, Queensland 4810, Australia
- AIMS@JCU, James Cook University, Townsville, Queensland 4811, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
- School of BioSciences, University of Melbourne, Parkville, Victoria 3010, Australia
- Corresponding author.
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Rocker MM, Noonan S, Humphrey C, Moya A, Willis BL, Bay LK. Expression of calcification and metabolism-related genes in response to elevated pCO2 and temperature in the reef-building coral Acropora millepora. Mar Genomics 2015; 24 Pt 3:313-8. [PMID: 26275825 DOI: 10.1016/j.margen.2015.08.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 08/05/2015] [Accepted: 08/05/2015] [Indexed: 02/07/2023]
Abstract
Declining health of scleractinian corals in response to deteriorating environmental conditions is widely acknowledged, however links between physiological and functional genomic responses of corals are less well understood. Here we explore growth and the expression of 20 target genes with putative roles in metabolism and calcification in the branching coral, Acropora millepora, in two separate experiments: 1) elevated pCO2 (464, 822, 1187 and 1638 μatm) and ambient temperature (27°C), and 2) elevated pCO2 (490 and 822 μatm) and temperature (28 and 31 °C). After 14 days of exposure to elevated pCO2 and ambient temperatures, no evidence of differential expression of either calcification or metabolism genes was detected between control and elevated pCO2 treatments. After 37 days of exposure to control and elevated pCO2, Ubiquinol-Cytochrome-C Reductase Subunit 2 gene (QCR2; a gene involved in complex III of the electron chain transport within the mitochondria and critical for generation of ATP) was significantly down-regulated in the elevated pCO2 treatment in both ambient and elevated temperature treatments. Overall, the general absence of a strong response to elevated pCO2 and temperature by the other 19 targeted calcification and metabolism genes suggests that corals may not be affected by these stressors on longer time scales (37 days). These results also highlight the potential for QCR2 to act as a biomarker of coral genomic responses to changing environments.
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Affiliation(s)
- Melissa M Rocker
- Australian Institute of Marine Science, PMB #3, Townsville MC, QLD 4810, Australia; AIMS@JCU, Australian Institute of Marine Science, James Cook University, Townsville, QLD 4811, Australia; College of Marine and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.
| | - Sam Noonan
- Australian Institute of Marine Science, PMB #3, Townsville MC, QLD 4810, Australia
| | - Craig Humphrey
- Australian Institute of Marine Science, PMB #3, Townsville MC, QLD 4810, Australia
| | - Aurelie Moya
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
| | - Bette L Willis
- College of Marine and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
| | - Line K Bay
- Australian Institute of Marine Science, PMB #3, Townsville MC, QLD 4810, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
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Thomas L, Kennington WJ, Stat M, Wilkinson SP, Kool JT, Kendrick GA. Isolation by resistance across a complex coral reef seascape. Proc Biol Sci 2015; 282:20151217. [PMID: 26224707 PMCID: PMC4528533 DOI: 10.1098/rspb.2015.1217] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 06/29/2015] [Indexed: 01/27/2023] Open
Abstract
A detailed understanding of the genetic structure of populations and an accurate interpretation of processes driving contemporary patterns of gene flow are fundamental to successful spatial conservation management. The field of seascape genetics seeks to incorporate environmental variables and processes into analyses of population genetic data to improve our understanding of forces driving genetic divergence in the marine environment. Information about barriers to gene flow (such as ocean currents) is used to define a resistance surface to predict the spatial genetic structure of populations and explain deviations from the widely applied isolation-by-distance model. The majority of seascape approaches to date have been applied to linear coastal systems or at large spatial scales (more than 250 km), with very few applied to complex systems at regional spatial scales (less than 100 km). Here, we apply a seascape genetics approach to a peripheral population of the broadcast-spawning coral Acropora spicifera across the Houtman Abrolhos Islands, a high-latitude complex coral reef system off the central coast of Western Australia. We coupled population genetic data from a panel of microsatellite DNA markers with a biophysical dispersal model to test whether oceanographic processes could explain patterns of genetic divergence. We identified significant variation in allele frequencies over distances of less than 10 km, with significant differentiation occurring between adjacent sites but not between the most geographically distant ones. Recruitment probabilities between sites based on simulated larval dispersal were projected into a measure of resistance to connectivity that was significantly correlated with patterns of genetic divergence, demonstrating that patterns of spatial genetic structure are a function of restrictions to gene flow imposed by oceanographic currents. This study advances our understanding of the role of larval dispersal on the fine-scale genetic structure of coral populations across a complex island system and applies a methodological framework that can be tailored to suit a variety of marine organisms with a range of life-history characteristics.
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Affiliation(s)
- Luke Thomas
- The UWA Oceans Institute, School of Plant Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - W Jason Kennington
- Centre for Evolutionary Biology, School of Animal Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Michael Stat
- Trace and Environmental DNA (TrEnD) Laboratory, Department of Environment and Agriculture, Curtin University, Bentley, Western Australia 6102, Australia
| | - Shaun P Wilkinson
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Johnathan T Kool
- Geoscience Australia, Symonston, Australian Capital Territory 2601, Australia
| | - Gary A Kendrick
- The UWA Oceans Institute, School of Plant Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia
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Dixon GB, Davies SW, Aglyamova GA, Meyer E, Bay LK, Matz MV. CORAL REEFS. Genomic determinants of coral heat tolerance across latitudes. Science 2015; 348:1460-2. [PMID: 26113720 DOI: 10.1126/science.1261224] [Citation(s) in RCA: 251] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
As global warming continues, reef-building corals could avoid local population declines through "genetic rescue" involving exchange of heat-tolerant genotypes across latitudes, but only if latitudinal variation in thermal tolerance is heritable. Here, we show an up-to-10-fold increase in odds of survival of coral larvae under heat stress when their parents come from a warmer lower-latitude location. Elevated thermal tolerance was associated with heritable differences in expression of oxidative, extracellular, transport, and mitochondrial functions that indicated a lack of prior stress. Moreover, two genomic regions strongly responded to selection for thermal tolerance in interlatitudinal crosses. These results demonstrate that variation in coral thermal tolerance across latitudes has a strong genetic basis and could serve as raw material for natural selection.
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Affiliation(s)
- Groves B Dixon
- Department of Integrative Biology, University of Texas at Austin, 205 W. 24th Street C0990, Austin, TX 78712, USA
| | - Sarah W Davies
- Department of Integrative Biology, University of Texas at Austin, 205 W. 24th Street C0990, Austin, TX 78712, USA
| | - Galina A Aglyamova
- Department of Integrative Biology, University of Texas at Austin, 205 W. 24th Street C0990, Austin, TX 78712, USA
| | - Eli Meyer
- Department of Integrative Biology, Oregon State University, 3106 Cordley Hall, Corvallis, OR 97331, USA
| | - Line K Bay
- Australian Institute of Marine Science, PMB 3, Townsville MC, Queensland 4810, Australia.
| | - Mikhail V Matz
- Department of Integrative Biology, University of Texas at Austin, 205 W. 24th Street C0990, Austin, TX 78712, USA.
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30
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van Oppen MJH, Lukoschek V, Berkelmans R, Peplow LM, Jones AM. A population genetic assessment of coral recovery on highly disturbed reefs of the Keppel Island archipelago in the southern Great Barrier Reef. PeerJ 2015; 3:e1092. [PMID: 26244109 PMCID: PMC4517960 DOI: 10.7717/peerj.1092] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 06/18/2015] [Indexed: 01/28/2023] Open
Abstract
Coral reefs surrounding the islands lying close to the coast are unique to the Great Barrier Reef (GBR) in that they are frequently exposed to disturbance events including floods caused by cyclonic rainfall, strong winds and occasional periods of prolonged above-average temperatures during summer. In one such group of islands in the southern GBR, the Keppel Island archipelago, climate-driven disturbances frequently result in major coral mortality. Whilst these island reefs have clearly survived such dramatic disturbances in the past, the consequences of extreme mortality events may include the loss of genetic diversity, and hence adaptive potential, and a reduction in fitness due to inbreeding, especially if new recruitment from external sources is limited. Here we examined the level of isolation of the Keppel Island group as well as patterns of gene flow within the Keppel Islands using 10 microsatellite markers in nine populations of the coral, Acropora millepora. Bayesian cluster analysis and assignment tests indicated gene flow is restricted, but not absent, between the outer and inner Keppel Island groups, and that extensive gene flow exists within each of these island groups. Comparison of the Keppel Island data with results from a previous GBR-wide study that included a single Keppel Island population, confirmed that A. millepora in the Keppel Islands is genetically distinct from populations elsewhere on the GBR, with exception of the nearby inshore High Peak Reef just north of the Keppel Islands. We compared patterns of genetic diversity in the Keppel Island populations with those from other GBR populations and found them to be slightly, but significantly lower, consistent with the archipelago being geographically isolated, but there was no evidence for recent bottlenecks or deviation from mutation-drift equilibrium. A high incidence of private alleles in the Keppel Islands, particularly in the outer islands, supports their relative isolation and contributes to the conservation value of the archipelago. The lack of evidence for genetic erosion, in combination with our observation that the North Keppel Island population samples collected in 2002 and 2008, respectively, exhibited a pairwise genetic distance of zero, supports previous published work indicating that, following bleaching, Acropora corals in the Keppel Islands predominantly recover from regrowth of small amounts of remaining live tissue in apparently dead coral colonies. This is likely supplemented by recruitment of larvae from genetically similar, less disturbed populations at nearby reefs, particularly following extreme flood events.
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Affiliation(s)
- Madeleine J H van Oppen
- Australian Institute of Marine Science , Queensland , Australia ; School of BioSciences, The University of Melbourne , Parkville, Melbourne, Victoria , Australia ; ARC Centre of Excellence for Coral Reef Studies, James Cook University , Townsville, Queensland , Australia
| | - Vimoksalehi Lukoschek
- ARC Centre of Excellence for Coral Reef Studies, James Cook University , Townsville, Queensland , Australia
| | - Ray Berkelmans
- Australian Institute of Marine Science , Queensland , Australia
| | - Lesa M Peplow
- Australian Institute of Marine Science , Queensland , Australia
| | - Alison M Jones
- Central Queensland University , Rockhampton, Queensland , Australia
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31
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Capper RL, Jin YK, Lundgren PB, Peplow LM, Matz MV, van Oppen MJH. Quantitative high resolution melting: two methods to determine SNP allele frequencies from pooled samples. BMC Genet 2015; 16:62. [PMID: 26070466 PMCID: PMC4465018 DOI: 10.1186/s12863-015-0222-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 05/27/2015] [Indexed: 01/06/2023] Open
Abstract
Background The advent of next-generation sequencing has brought about an explosion of single nucleotide polymorphism (SNP) data in non-model organisms; however, profiling these SNPs across multiple natural populations still requires substantial time and resources. Results Here, we introduce two cost-efficient quantitative High Resolution Melting (qHRM) methods for measuring allele frequencies at known SNP loci in pooled DNA samples: the “peaks” method, which can be applied to large numbers of SNPs, and the “curves” method, which is more labor intensive but also slightly more accurate. Using the reef-building coral Acropora millepora, we show that both qHRM methods can recover the allele proportions from mixtures prepared using two or more individuals of known genotype. We further demonstrate advantages of each method over previously published methods; specifically, the “peaks” method can be rapidly scaled to screen several hundred SNPs at once, whereas the “curves” method is better suited for smaller numbers of SNPs. Conclusions Compared to genotyping individual samples, these methods can save considerable effort and genotyping costs when relatively few candidate SNPs must be profiled across a large number of populations. One of the main applications of this method could be validation of SNPs of interest identified in population genomic studies. Electronic supplementary material The online version of this article (doi:10.1186/s12863-015-0222-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Roxana L Capper
- Department of Cell and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA.
| | - Young K Jin
- School of Marine and Tropical Biology, James Cook University, Townsville, Qld, 4811, Australia. .,Australian Institute of Marine Science, PMB3, Townsville MC, Qld, 4810, Australia.
| | - Petra B Lundgren
- Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Monash University, Clayton, VIC, 3800, Australia.
| | - Lesa M Peplow
- Australian Institute of Marine Science, PMB3, Townsville MC, Qld, 4810, Australia.
| | - Mikhail V Matz
- Department of Cell and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA.
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Dixon GB, Bay LK, Matz MV. Bimodal signatures of germline methylation are linked with gene expression plasticity in the coral Acropora millepora. BMC Genomics 2014; 15:1109. [PMID: 25511458 PMCID: PMC4378018 DOI: 10.1186/1471-2164-15-1109] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 12/10/2014] [Indexed: 11/24/2022] Open
Abstract
Background In invertebrates, genes belonging to dynamically regulated functional categories appear to be less methylated than “housekeeping” genes, suggesting that DNA methylation may modulate gene expression plasticity. To date, however, experimental evidence to support this hypothesis across different natural habitats has been lacking. Results Gene expression profiles were generated from 30 pairs of genetically identical fragments of coral Acropora millepora reciprocally transplanted between distinct natural habitats for 3 months. Gene expression was analyzed in the context of normalized CpG content, a well-established signature of historical germline DNA methylation. Genes with weak methylation signatures were more likely to demonstrate differential expression based on both transplant environment and population of origin than genes with strong methylation signatures. Moreover, the magnitude of expression differences due to environment and population were greater for genes with weak methylation signatures. Conclusions Our results support a connection between differential germline methylation and gene expression flexibility across environments and populations. Studies of phylogenetically basal invertebrates such as corals will further elucidate the fundamental functional aspects of gene body methylation in Metazoa. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1109) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Groves B Dixon
- Institute for Cell and Molecular Biology, University of Texas Austin, Austin, USA.
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Davies SW, Treml EA, Kenkel CD, Matz MV. Exploring the role of Micronesian islands in the maintenance of coral genetic diversity in the Pacific Ocean. Mol Ecol 2014; 24:70-82. [DOI: 10.1111/mec.13005] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 11/04/2014] [Accepted: 11/07/2014] [Indexed: 11/27/2022]
Affiliation(s)
- S. W. Davies
- Department of Integrative Biology; The University of Texas at Austin; 1 University Station C0990 Austin TX 78712 USA
| | - E. A. Treml
- Department of Zoology; University of Melbourne; Melbourne Vic. 3010 Australia
| | - C. D. Kenkel
- Department of Integrative Biology; The University of Texas at Austin; 1 University Station C0990 Austin TX 78712 USA
| | - M. V. Matz
- Department of Integrative Biology; The University of Texas at Austin; 1 University Station C0990 Austin TX 78712 USA
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Trematodes of the Great Barrier Reef, Australia: emerging patterns of diversity and richness in coral reef fishes. Int J Parasitol 2014; 44:929-39. [DOI: 10.1016/j.ijpara.2014.08.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/19/2014] [Accepted: 08/20/2014] [Indexed: 11/17/2022]
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Torda G, Lundgren P, Willis BL, van Oppen MJH. Genetic assignment of recruits reveals short- and long-distance larval dispersal inPocillopora damicornison the Great Barrier Reef. Mol Ecol 2013; 22:5821-34. [DOI: 10.1111/mec.12539] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 09/08/2013] [Accepted: 09/18/2013] [Indexed: 11/30/2022]
Affiliation(s)
- G. Torda
- School of Marine and Tropical Biology; James Cook University; Townsville QLD 4811 Australia
- Australian Institute of Marine Science; PMB 3 MC Townsville QLD 4810 Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies; James Cook University; Townsville QLD 4814 Australia
- AIMS@JCU; Townsville QLD 4814 Australia
| | - P. Lundgren
- Australian Institute of Marine Science; PMB 3 MC Townsville QLD 4810 Australia
- Great Barrier Reef Marine Park Authority; PO Box 1379 Townsville QLD 4810 Australia
- School of Biomedical Sciences; Monash University; Clayton VIC 3800 Australia
| | - B. L. Willis
- School of Marine and Tropical Biology; James Cook University; Townsville QLD 4811 Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies; James Cook University; Townsville QLD 4814 Australia
| | - M. J. H. van Oppen
- School of Marine and Tropical Biology; James Cook University; Townsville QLD 4811 Australia
- Australian Institute of Marine Science; PMB 3 MC Townsville QLD 4810 Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies; James Cook University; Townsville QLD 4814 Australia
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36
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Torda G, Lundgren P, Willis BL, van Oppen MJH. Revisiting the connectivity puzzle of the common coralPocillopora damicornis. Mol Ecol 2013; 22:5805-20. [DOI: 10.1111/mec.12540] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 09/07/2013] [Accepted: 09/17/2013] [Indexed: 11/28/2022]
Affiliation(s)
- G. Torda
- School of Marine and Tropical Biology; James Cook University; Townsville Qld 4811 Australia
- Australian Institute of Marine Science; PMB 3 MC Townsville Qld 4810 Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies; James Cook University; Townsville Qld 4814 Australia
- AIMS@JCU; Townsville Qld 4814 Australia
| | - P. Lundgren
- Australian Institute of Marine Science; PMB 3 MC Townsville Qld 4810 Australia
- Great Barrier Reef Marine Park Authority; PO Box 1379 Townsville Qld 4810 Australia
- School of Biomedical Sciences; Monash University; Clayton Vic 3800 Australia
| | - B. L. Willis
- School of Marine and Tropical Biology; James Cook University; Townsville Qld 4811 Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies; James Cook University; Townsville Qld 4814 Australia
| | - M. J. H. van Oppen
- School of Marine and Tropical Biology; James Cook University; Townsville Qld 4811 Australia
- Australian Institute of Marine Science; PMB 3 MC Townsville Qld 4810 Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies; James Cook University; Townsville Qld 4814 Australia
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Lukoschek V, Cross P, Torda G, Zimmerman R, Willis BL. The importance of coral larval recruitment for the recovery of reefs impacted by cyclone Yasi in the central Great Barrier Reef. PLoS One 2013; 8:e65363. [PMID: 23755223 PMCID: PMC3673992 DOI: 10.1371/journal.pone.0065363] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 05/01/2013] [Indexed: 11/18/2022] Open
Abstract
Cyclone Yasi, one of the most severe tropical storms on record, crossed the central Great Barrier Reef (GBR) in February 2011, bringing wind speeds of up to 285 km hr−1 and wave heights of at least 10 m, and causing massive destruction to exposed reefs in the Palm Island Group. Following the cyclone, mean (± S.E.) hard coral cover ranged from just 2.1 (0.2) % to 5.3 (0.4) % on exposed reefs and no reproductively mature colonies of any species of Acropora remained. Although no fragments of Acropora were found at impacted exposed sites following the cyclone, small juvenile colonies of Acropora (<10 cm diameter) were present, suggesting that their small size and compact morphologies enabled them to survive the cyclone. By contrast, sheltered reefs appeared to be unaffected by the cyclone. Mean (± S.E.) hard coral cover ranged from 18.2 (2.4) % to 30.0 (1.0) % and a large proportion of colonies of Acropora were reproductively mature. Macroalgae accounted for 8 to 16% of benthic cover at exposed sites impacted by cyclone Yasi but were absent at sheltered sites. Mean (± S.E.) recruitment of acroporids to settlement tiles declined from 25.3 (4.8) recruits tile−1 in the pre-cyclone spawning event (2010) to 15.4 (2.2) recruits tile−1 in the first post-cyclone spawning event (2011). Yet, post-cyclone recruitment did not differ between exposed (15.2±2.1 S.E.) and sheltered sites (15.6±2.2 S.E.), despite the loss of reproductive colonies at the exposed sites, indicating larval input from external sources. Spatial variation in impacts, the survival of small colonies, and larval replenishment to impacted reefs suggest that populations of Acropora have the potential to recover from this severe disturbance, provided that the Palm Islands are not impacted by acute disturbances or suffer additional chronic stressors in the near future.
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Affiliation(s)
- Vimoksalehi Lukoschek
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia.
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Bay LK, Guérécheau A, Andreakis N, Ulstrup KE, Matz MV. Gene expression signatures of energetic acclimatisation in the reef building coral Acropora millepora. PLoS One 2013; 8:e61736. [PMID: 23671571 PMCID: PMC3650039 DOI: 10.1371/journal.pone.0061736] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 03/13/2013] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Understanding the mechanisms by which natural populations cope with environmental stress is paramount to predict their persistence in the face of escalating anthropogenic impacts. Reef-building corals are increasingly exposed to local and global stressors that alter nutritional status causing reduced fitness and mortality, however, these responses can vary considerably across species and populations. METHODOLOGY/PRINCIPAL FINDINGS We compare the expression of 22 coral host genes in individuals from an inshore and an offshore reef location using quantitative Reverse Transcription-PCR (qRT-PCR) over the course of 26 days following translocation into a shaded, filtered seawater environment. Declines in lipid content and PSII activity of the algal endosymbionts (Symbiodinium ITS-1 type C2) over the course of the experiment indicated that heterotrophic uptake and photosynthesis were limited, creating nutritional deprivation conditions. Regulation of coral host genes involved in metabolism, CO2 transport and oxidative stress could be detected already after five days, whereas PSII activity took twice as long to respond. Opposing expression trajectories of Tgl, which releases fatty acids from the triacylglycerol storage, and Dgat1, which catalyses the formation of triglycerides, indicate that the decline in lipid content can be attributed, at least in part, by mobilisation of triacylglycerol stores. Corals from the inshore location had initially higher lipid content and showed consistently elevated expression levels of two genes involved in metabolism (aldehyde dehydrogenase) and calcification (carbonic anhydrase). CONCLUSIONS/SIGNIFICANCE Coral host gene expression adjusts rapidly upon change in nutritional conditions, and therefore can serve as an early signature of imminent coral stress. Consistent gene expression differences between populations indicate that corals acclimatize and/or adapt to local environments. Our results set the stage for analysis of these processes in natural coral populations, to better understand the responses of coral communities to global climate change and to develop more efficient management strategies.
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Affiliation(s)
- Line K Bay
- Climate Change and Ocean Acidification Team, Australian Institute of Marine Science, Townsville, Queensland, Australia.
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Howells EJ, Berkelmans R, van Oppen MJH, Willis BL, Bay LK. Historical thermal regimes define limits to coral acclimatization. Ecology 2013; 94:1078-88. [DOI: 10.1890/12-1257.1] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Granados-Cifuentes C, Bellantuono AJ, Ridgway T, Hoegh-Guldberg O, Rodriguez-Lanetty M. High natural gene expression variation in the reef-building coral Acropora millepora: potential for acclimative and adaptive plasticity. BMC Genomics 2013; 14:228. [PMID: 23565725 PMCID: PMC3630057 DOI: 10.1186/1471-2164-14-228] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 02/27/2013] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Ecosystems worldwide are suffering the consequences of anthropogenic impact. The diverse ecosystem of coral reefs, for example, are globally threatened by increases in sea surface temperatures due to global warming. Studies to date have focused on determining genetic diversity, the sequence variability of genes in a species, as a proxy to estimate and predict the potential adaptive response of coral populations to environmental changes linked to climate changes. However, the examination of natural gene expression variation has received less attention. This variation has been implicated as an important factor in evolutionary processes, upon which natural selection can act. RESULTS We acclimatized coral nubbins from six colonies of the reef-building coral Acropora millepora to a common garden in Heron Island (Great Barrier Reef, GBR) for a period of four weeks to remove any site-specific environmental effects on the physiology of the coral nubbins. By using a cDNA microarray platform, we detected a high level of gene expression variation, with 17% (488) of the unigenes differentially expressed across coral nubbins of the six colonies (jsFDR-corrected, p < 0.01). Among the main categories of biological processes found differentially expressed were transport, translation, response to stimulus, oxidation-reduction processes, and apoptosis. We found that the transcriptional profiles did not correspond to the genotype of the colony characterized using either an intron of the carbonic anhydrase gene or microsatellite loci markers. CONCLUSION Our results provide evidence of the high inter-colony variation in A. millepora at the transcriptomic level grown under a common garden and without a correspondence with genotypic identity. This finding brings to our attention the importance of taking into account natural variation between reef corals when assessing experimental gene expression differences. The high transcriptional variation detected in this study is interpreted and discussed within the context of adaptive potential and phenotypic plasticity of reef corals. Whether this variation will allow coral reefs to survive to current challenges remains unknown.
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Affiliation(s)
- Camila Granados-Cifuentes
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Anthony J Bellantuono
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Tyrone Ridgway
- Oceanica Consulting Pty Ltd, PO Box 462, Wembley, WA, 6913, Australia
- The Oceans Institute, University of Western Australia, Crawley, WA, 6009, Australia
| | - Ove Hoegh-Guldberg
- ARC Centre of Excellence for Coral Reef Studies and Coral Genomics Group, School of Pharmacy and Molecular Sciences, James Cook University, Townsville, QLD, Australia
- Global Change Institute, The University of Queensland, St Lucia, QLD, Australia
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Lundgren P, Vera JC, Peplow L, Manel S, van Oppen MJH. Genotype - environment correlations in corals from the Great Barrier Reef. BMC Genet 2013; 14:9. [PMID: 23433436 PMCID: PMC3599201 DOI: 10.1186/1471-2156-14-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 01/03/2013] [Indexed: 12/13/2022] Open
Abstract
Background Knowledge of genetic markers that are correlated to stress tolerance may improve spatial mapping of reef vulnerability and can inform restoration efforts, including the choice of genotypes for breeding and reseeding. In this manuscript we present two methods for screening transcriptome data for candidate genetic markers in two reef building corals, Acropora millepora and Pocillopora damicornis (types α and β). In A. millepora, Single Nucleotide Polymorphisms (SNPs) were pre-selected by targeting genes believed to be involved in the coral thermal stress responses. In P. damicornis (type α and β), SNPs showing varying allele frequencies between two populations from distinct environments were pre-selected. Allele frequencies at nine, five and eight of the pre-selected SNP loci were correlated against gradients of water clarity and temperature in a large number of populations along the Great Barrier Reef. Results A significant correlation between environmental category and SNP allele frequency was detected in up to 55% of the tested loci, which is an exceptional success rate for these types of tests. In P. damicornis, SNP allele frequencies of β-hexosaminidase and Elongation factor 1-α were significantly correlated to temperature in type α and to temperature and/or water clarity respectively in type β. Type α also showed a correlation between water clarity and SNP allele frequency in a gene of unknown function. In A. millepora, allele frequencies at five (β-gamma crystallin, Galaxin, Ubiquitin, Ligand of Numb X2 and Thioredoxin) SNP loci showed significant correlations. Conclusions After validation of these candidate loci through laboratory or field assessment of relative stress tolerance of colonies harbouring different alleles, it is anticipated that a proportion of these markers may represent the first coral candidate Quantitative Trait Loci for environmental stress tolerance and provide an important genetic tool that can be incorporated into spatial management decisions and restoration efforts of coral reefs. One pertinent example would be to combine spatial data of tolerant populations with genetic connectivity and thus identify high priority conservation reefs and implement targeted coral husbandry and active restoration efforts that use locally- and stress-adapted genotypes.
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Affiliation(s)
- Petra Lundgren
- Australian Institute of Marine Science, PMB No 3, Townsville MC, QLD, 4810, Australia.
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Seymour M, Ott K, Guertin D, Golden H, McDonald D, Ben-David M. Early Holocene glacial retreat isolated populations of river otters (Lontra canadensis) along the Alaskan coast. CAN J ZOOL 2012. [DOI: 10.1139/z2012-082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pleistocene climatic oscillations have resulted in high rates of speciation. Lesser known are speciation events related to recent glacial retreats. During the early Holocene many Alaskan coastal glaciers receded, exposing much of the Kodiak Island Archipelago (KOD), the Kenai Peninsula, and Prince William Sound (PWS). Using fecal DNA analyses on samples collected in KOD, PWS, Kenai Fjords National Park (KEFJ), Katmai National Park and Preserve (KATM), and Vancouver Island, British Columbia (BC), we found isolation by distance to be an important mechanism for the divergence of populations of river otters ( Lontra canadensis (Schreber, 1777)) along the Pacific coast. Nonetheless, our results also demonstrated that KOD river otters appear to be more isolated genetically from their mainland conspecifics (approximately 50 km away), as river otters inhabiting PWS are from those in BC (over 2500 km away). In addition, KATM and KOD otters likely differentiated from one ancestral stock that inhabited the southwestern shores of Alaska during the Pleistocene and was isolated from more easterly populations by distance. The low genetic diversity among KOD river otters, compared with similar subpopulations in PWS, is likely the result of a founder effect and limited gene flow among the different islands within the Archipelago. Our observation that glacial retreat, rising sea levels, and formation of the Gulf of Alaska Coastal Current in the early Holocene likely led to divergence of populations of river otters, a highly mobile semiaquatic mammal, highlights the potential for future speciation events related to current climate change and ocean currents in coastal animal populations.
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Affiliation(s)
- M.S. Seymour
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - K.E. Ott
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - D.A. Guertin
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - H.N. Golden
- Division of Wildlife Conservation, Alaska Department of Fish and Game, Anchorage, AK 99518, USA
| | - D.B. McDonald
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
- Program in Ecology, University of Wyoming, Laramie, WY 82071, USA
| | - M. Ben-David
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
- Program in Ecology, University of Wyoming, Laramie, WY 82071, USA
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Richards ZT, Oppen MJH. Rarity and genetic diversity in Indo-Pacific Acropora corals. Ecol Evol 2012; 2:1867-88. [PMID: 22957189 PMCID: PMC3433991 DOI: 10.1002/ece3.304] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 05/24/2012] [Accepted: 05/25/2012] [Indexed: 11/21/2022] Open
Abstract
Among various potential consequences of rarity is genetic erosion. Neutral genetic theory predicts that rare species will have lower genetic diversity than common species. To examine the association between genetic diversity and rarity, variation at eight DNA microsatellite markers was documented for 14 Acropora species that display different patterns of distribution and abundance in the Indo-Pacific Ocean. Our results show that the relationship between rarity and genetic diversity is not a positive linear association because, contrary to expectations, some rare species are genetically diverse and some populations of common species are genetically depleted. Our data suggest that inbreeding is the most likely mechanism of genetic depletion in both rare and common corals, and that hybridization is the most likely explanation for higher than expected levels of genetic diversity in rare species. A significant hypothesis generated from our study with direct conservation implications is that as a group, Acropora corals have lower genetic diversity at neutral microsatellite loci than may be expected from their taxonomic diversity, and this may suggest a heightened susceptibility to environmental change. This hypothesis requires validation based on genetic diversity estimates derived from a large portion of the genome.
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