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Ferrari A, Spiga M, Rodriguez MD, Fiorentino F, Gil-Herrera J, Hernandez P, Hidalgo M, Johnstone C, Khemiri S, Mokhtar-Jamaï K, Nadal I, Pérez M, Sammartino S, Vasconcellos M, Cariani A. Matching an Old Marine Paradigm: Limitless Connectivity in a Deep-Water Fish over a Large Distance. Animals (Basel) 2023; 13:2691. [PMID: 37684955 PMCID: PMC10486518 DOI: 10.3390/ani13172691] [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: 07/06/2023] [Revised: 08/14/2023] [Accepted: 08/17/2023] [Indexed: 09/10/2023] Open
Abstract
Investigations of population structuring in wild species are fundamental to complete the bigger picture defining their ecological and biological roles in the marine realm, to estimate their recovery capacity triggered by human disturbance and implement more efficient management strategies for fishery resources. The Blackspot Seabream (Pagellus bogaraveo, Brünnich 1768) is a commercially valuable deep-water fish highly exploited over past decades. Considering its exploitation status, deepening the knowledge of intraspecific variability, genetic diversity, and differentiation using high-performing molecular markers is considered an important step for a more effective stock assessment and fishery management. With one of the largest efforts conceived of and completed by countries overlooking the Atlantic and Mediterranean coasts in recent years, a total of 320 individuals were collected from different fishing grounds in the Mediterranean Sea and Atlantic Ocean and analysed using 29 microsatellite loci. We applied multiple statistical approaches to investigate the species' connectivity and population structure across most of its described distribution area. Considering the incomplete knowledge regarding the migratory behaviour of adults, here we suggest the importance of egg and larval dispersal in sustaining the observed genetic connectivity on such a large geographical scale.
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Affiliation(s)
- Alice Ferrari
- Department of Biological, Geological & Environmental Sciences (BiGeA), University of Bologna, 40126 Bologna, Italy; (M.S.); (A.C.)
| | - Martina Spiga
- Department of Biological, Geological & Environmental Sciences (BiGeA), University of Bologna, 40126 Bologna, Italy; (M.S.); (A.C.)
| | | | - Fabio Fiorentino
- Institute for Marine Biological Resources and Biotechnology (IRBIM), National Research Council (CNR), 91026 Trapani, Italy;
- Stazione Zoologica Anton Dorhn, 90149 Palermo, Italy
| | | | - Pilar Hernandez
- Technical Unit for Western Mediterranean, General Fisheries Commission for the Mediterranean (GFCM), Fisheries and Aquaculture Division, Food and Agricultural Organization (FAO) of the United Nations, 29014 Malaga, Spain;
| | - Manuel Hidalgo
- Oceanographic Center of the Balearic Islands, Ecosystem Oceanography Group (GRECO), Spanish Institute of Oceanography (IEO, CSIC), 07015 Palma, Spain;
| | - Carolina Johnstone
- Centro Oceanográfico de Málaga (IEO, CSIC), 29640 Málaga, Spain; (M.D.R.); (C.J.)
| | - Sana Khemiri
- Institut National des Sciences et Technologies de la Mer, Salammbô 2025, Tunisia;
| | - Kenza Mokhtar-Jamaï
- Laboratoire de Génétique des Populations Halieutiques, Institut National de Recherche Halieutique (INRH), Centre Régional d’Agadir, Agadir 80000, Morocco;
| | - Irene Nadal
- Physical Oceanography Group, Instituto de Biotecnología y Desarrollo Azul (IBYDA), Universidad de Málaga, 29071 Málaga, Spain;
| | - Montse Pérez
- AquaCOV, Centro Oceanográfico de Vigo (IEO, CSIC), 36390 Pontevedra, Spain;
| | - Simone Sammartino
- Physical Oceanography Group, Instituto de Ingeniería Oceánica (IIO), Universidad de Málaga, 29071 Málaga, Spain;
| | - Marcelo Vasconcellos
- Fisheries and Aquaculture Division, Food and Agriculture Organization (FAO) of the United Nations, 00153 Rome, Italy;
| | - Alessia Cariani
- Department of Biological, Geological & Environmental Sciences (BiGeA), University of Bologna, 40126 Bologna, Italy; (M.S.); (A.C.)
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Li F, Liu X, Zhu J, Li J, Gao K, Zhao C. The Role of Genetic Factors in the Differential Invasion Success of Two Spartina Species in China. FRONTIERS IN PLANT SCIENCE 2022; 13:909429. [PMID: 35712568 PMCID: PMC9196123 DOI: 10.3389/fpls.2022.909429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
Biological invasions have become one of the greatest threats to global biodiversity and ecosystem conservation. Most previous studies have revealed how successful invasive species adapt to new environments and climate change through phenotypic and genetic evolution. Some researchers suggested that understanding unsuccessful or less successful biological invasions might be important for understanding the relationships between invasion adaptability and climate factors. We compared the sexual reproduction ability, genetic diversity, and gene × environment interaction in two intentionally introduced alien species in China (Spartina anglica and Spartina alterniflora) based on restriction site-associated DNA (RAD) sequencing. After more than 50 years, the distribution of S. alterniflora has rapidly expanded, while S. anglica has experienced extreme dieback. A total of 212,939 single nucleotide polymorphisms (SNPs) for the two Spartina species were used for analysis. The multilocus genotype (MLG) analysis revealed that clonal reproduction was the prevalent mode of reproduction in both species, indicating that a change in the mode of reproduction was not the key factor enabling successful invasion by Spartina. All genetic diversity indicators (He, Ho, π) in S. alterniflora populations were at least two times higher than those in S. anglica populations, respectively (p < 0.001). Furthermore, the population genetic structure and stronger patterns of climate-associated loci provided support for rapid adaptive evolution in the populations of S. alterniflora in China. Altogether, our results highlight the importance of genetic diversity and local adaptation, which were driven by multiple source populations, in increasing the invasiveness of S. alterniflora.
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Chen C, Parejo M, Momeni J, Langa J, Nielsen RO, Shi W, Vingborg R, Kryger P, Bouga M, Estonba A, Meixner M. Population Structure and Diversity in European Honey Bees (Apis mellifera L.)—An Empirical Comparison of Pool and Individual Whole-Genome Sequencing. Genes (Basel) 2022; 13:genes13020182. [PMID: 35205227 PMCID: PMC8872436 DOI: 10.3390/genes13020182] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 12/27/2021] [Accepted: 12/30/2021] [Indexed: 01/27/2023] Open
Abstract
Background: Whole-genome sequencing has become routine for population genetic studies. Sequencing of individuals provides maximal data but is rather expensive and fewer samples can be studied. In contrast, sequencing a pool of samples (pool-seq) can provide sufficient data, while presenting less of an economic challenge. Few studies have compared the two approaches to infer population genetic structure and diversity in real datasets. Here, we apply individual sequencing (ind-seq) and pool-seq to the study of Western honey bees (Apis mellifera). Methods: We collected honey bee workers that belonged to 14 populations, including 13 subspecies, totaling 1347 colonies, who were individually (139 individuals) and pool-sequenced (14 pools). We compared allele frequencies, genetic diversity estimates, and population structure as inferred by the two approaches. Results: Pool-seq and ind-seq revealed near identical population structure and genetic diversities, albeit at different costs. While pool-seq provides genome-wide polymorphism data at considerably lower costs, ind-seq can provide additional information, including the identification of population substructures, hybridization, or individual outliers. Conclusions: If costs are not the limiting factor, we recommend using ind-seq, as population genetic structure can be inferred similarly well, with the advantage gained from individual genetic information. Not least, it also significantly reduces the effort required for the collection of numerous samples and their further processing in the laboratory.
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Affiliation(s)
- Chao Chen
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China;
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture and Rural Affairs, Beijing 100093, China
- Correspondence: (C.C.); (M.P.)
| | - Melanie Parejo
- Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain; (J.L.); (A.E.)
- Swiss Bee Research Center, Agroscope, 3003 Bern, Switzerland
- Correspondence: (C.C.); (M.P.)
| | - Jamal Momeni
- Eurofins Genomics, 8200 Aarhus, Denmark; (J.M.); (R.O.N.); (R.V.)
| | - Jorge Langa
- Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain; (J.L.); (A.E.)
| | | | - Wei Shi
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China;
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture and Rural Affairs, Beijing 100093, China
| | | | - Rikke Vingborg
- Eurofins Genomics, 8200 Aarhus, Denmark; (J.M.); (R.O.N.); (R.V.)
| | - Per Kryger
- Department of Agroecology, Aarhus University, 4200 Slagelse, Denmark;
| | - Maria Bouga
- Lab of Agricultural Zoology and Entomology, Agricultural University of Athens, 11855 Athens, Greece;
| | - Andone Estonba
- Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain; (J.L.); (A.E.)
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Paril JF, Balding DJ, Fournier-Level A. Optimizing sampling design and sequencing strategy for the genomic analysis of quantitative traits in natural populations. Mol Ecol Resour 2021; 22:137-152. [PMID: 34192415 DOI: 10.1111/1755-0998.13458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 05/02/2021] [Accepted: 06/25/2021] [Indexed: 11/27/2022]
Abstract
Mapping the genes underlying ecologically relevant traits in natural populations is fundamental to develop a molecular understanding of species adaptation. Current sequencing technologies enable the characterization of a species' genetic diversity across the landscape or even over its whole range. The relevant capture of the genetic diversity across the landscape is critical for a successful genetic mapping of traits and there are no clear guidelines on how to achieve an optimal sampling and which sequencing strategy to implement. Here we determine, through simulation, the sampling scheme that maximizes the power to map the genetic basis of a complex trait in an outbreeding species across an idealized landscape and draw genomic predictions for the trait, comparing individual and pool sequencing strategies. Our results show that quantitative trait locus detection power and prediction accuracy are higher when more populations over the landscape are sampled and this is more cost-effectively done with pool sequencing than with individual sequencing. Additionally, we recommend sampling populations from areas of high genetic diversity. As progress in sequencing enables the integration of trait-based functional ecology into landscape genomics studies, these findings will guide study designs allowing direct measures of genetic effects in natural populations across the environment.
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Affiliation(s)
- Jefferson F Paril
- School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia
| | - David J Balding
- School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia.,Melbourne Integrative Genomics, The University of Melbourne, Parkville, Victoria, Australia.,School of Mathematics and Statistics, The University of Melbourne, Parkville, Victoria, Australia
| | - Alexandre Fournier-Level
- School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia.,Melbourne Integrative Genomics, The University of Melbourne, Parkville, Victoria, Australia
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Hussain I, Raza RZ, Ali S, Abrar M, Abbasi AA. Molecular signatures of selection on the human GLI3 associated central nervous system specific enhancers. Dev Genes Evol 2021; 231:21-32. [PMID: 33655411 DOI: 10.1007/s00427-021-00672-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 02/09/2021] [Indexed: 11/25/2022]
Abstract
The zinc finger-containing transcription factor Gli3 is a key mediator of Hedgehog (Hh) signaling pathway. In vertebrates, Gli3 has widespread expression pattern during early embryonic development. Along the anteroposterior axes of the central nervous system (CNS), dorsoventral neural pattern elaboration is achieved through Hh mediated spatio-temporal deployment of Gli3 transcripts. Previously, we and others uncovered a set of enhancers that mediate many of the known aspects of Gli3 expression during neurogenesis. However, the potential role of Gli3 associated enhancers in trait evolution has not yet received any significant attention. Here, we investigate the evolutionary patterns of Gli3 associated CNS-specific enhancers that have been reported so far. A subset of these enhancers has undergone an accelerated rate of molecular evolution in the human lineage in comparison to other primates/mammals. These fast-evolving enhancers have acquired human-specific changes in transcription factor binding sites (TFBSs). These human-unique changes within subset of Gli3 associated CNS-specific enhancers were further validated as single nucleotide polymorphisms through 1000 Genome Project Phase 3 data. This work not only infers the molecular evolutionary patterns of Gli3 associated enhancers but also provides clues for putative genetic basis of the population-specificity of gene expression regulation.
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Affiliation(s)
- Irfan Hussain
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Rabail Zehra Raza
- Department of Biological Sciences, National University of Medical Sciences, The Mall, Rawalpindi, Pakistan
| | - Shahid Ali
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Muhammad Abrar
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Amir Ali Abbasi
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
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Emami-Khoyi A, Knapp IS, Monsanto DM, van Vuuren BJ, Toonen RJ, Teske PR. Genomic divergence and differential gene expression between crustacean ecotypes across a marine thermal gradient. Mar Genomics 2021; 58:100847. [PMID: 33637426 DOI: 10.1016/j.margen.2021.100847] [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: 09/10/2020] [Revised: 12/15/2020] [Accepted: 01/29/2021] [Indexed: 11/30/2022]
Abstract
Environmental gradients between marine biogeographical provinces separate distinct faunal communities. However, the absence of absolute dispersal barriers allows numerous species to occur on both sides of such boundaries. While the regional populations of such widespread species are often morphologically indistinguishable from each other, genetic evidence suggests that they represent unique ecotypes, and likely even cryptic species, that may be uniquely adapted to their local environment. Here, we explored genomic divergence in four sympatric southern African decapod crustaceans whose ranges span the boundary between the cool-temperate west coast (south-eastern Atlantic) and the warm-temperate south coast (south-western Indian Ocean) near the southern tip of the African continent. Using genome-wide data, we found that all four species comprise distinct west coast and south coast ecotypes, with molecular dating suggesting divergence during the Pleistocene. Transcriptomic data from the hepatopancreas of twelve specimens of one of these species, the mudprawn Upogebia africana, which were exposed to either 10 °C or 20 °C, showed a clear difference in gene expression profiles between the west- and south coast ecotypes. This difference was particularly clear at 10 °C, where individuals from the south coast experienced a 'transcriptomic shock'. This low temperature is more typical of the west coast during upwelling events, and the physiological stress experienced by the south coast ecotype under such conditions may explain its absence from that coastline. Our results shed new light on the processes involved in driving genomic divergence and incipient speciation along coastlines with porous dispersal barriers.
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Affiliation(s)
- Arsalan Emami-Khoyi
- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, University of Johannesburg, Auckland Park 2006, South Africa.
| | - Ingrid S Knapp
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, Hawai'i, Honolulu, HI, USA
| | - Daniela M Monsanto
- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, University of Johannesburg, Auckland Park 2006, South Africa
| | - Bettine Jansen van Vuuren
- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, University of Johannesburg, Auckland Park 2006, South Africa
| | - Robert J Toonen
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, Hawai'i, Honolulu, HI, USA
| | - Peter R Teske
- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, University of Johannesburg, Auckland Park 2006, South Africa.
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Nielsen ES, Henriques R, Beger M, Toonen RJ, von der Heyden S. Multi-model seascape genomics identifies distinct environmental drivers of selection among sympatric marine species. BMC Evol Biol 2020; 20:121. [PMID: 32938400 PMCID: PMC7493327 DOI: 10.1186/s12862-020-01679-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/24/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND As global change and anthropogenic pressures continue to increase, conservation and management increasingly needs to consider species' potential to adapt to novel environmental conditions. Therefore, it is imperative to characterise the main selective forces acting on ecosystems, and how these may influence the evolutionary potential of populations and species. Using a multi-model seascape genomics approach, we compare putative environmental drivers of selection in three sympatric southern African marine invertebrates with contrasting ecology and life histories: Cape urchin (Parechinus angulosus), Common shore crab (Cyclograpsus punctatus), and Granular limpet (Scutellastra granularis). RESULTS Using pooled (Pool-seq), restriction-site associated DNA sequencing (RAD-seq), and seven outlier detection methods, we characterise genomic variation between populations along a strong biogeographical gradient. Of the three species, only S. granularis showed significant isolation-by-distance, and isolation-by-environment driven by sea surface temperatures (SST). In contrast, sea surface salinity (SSS) and range in air temperature correlated more strongly with genomic variation in C. punctatus and P. angulosus. Differences were also found in genomic structuring between the three species, with outlier loci contributing to two clusters in the East and West Coasts for S. granularis and P. angulosus, but not for C. punctatus. CONCLUSION The findings illustrate distinct evolutionary potential across species, suggesting that species-specific habitat requirements and responses to environmental stresses may be better predictors of evolutionary patterns than the strong environmental gradients within the region. We also found large discrepancies between outlier detection methodologies, and thus offer a novel multi-model approach to identifying the principal environmental selection forces acting on species. Overall, this work highlights how adding a comparative approach to seascape genomics (both with multiple models and species) can elucidate the intricate evolutionary responses of ecosystems to global change.
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Affiliation(s)
- Erica S Nielsen
- Evolutionary Genomics Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa
| | - Romina Henriques
- Evolutionary Genomics Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa.,Technical University of Denmark, National Institute of Aquatic Resources, Section for Marine Living Resources, Velsøvej 39, 8600, Silkeborg, Denmark
| | - Maria Beger
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Robert J Toonen
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, 96744, USA
| | - Sophie von der Heyden
- Evolutionary Genomics Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa.
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Phair NL, Toonen RJ, Knapp ISS, von der Heyden S. Anthropogenic pressures negatively impact genomic diversity of the vulnerable seagrass Zostera capensis. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 255:109831. [PMID: 32063316 DOI: 10.1016/j.jenvman.2019.109831] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 11/03/2019] [Accepted: 11/05/2019] [Indexed: 06/10/2023]
Abstract
Zostera capensis is a keystone species providing essential ecosystem services to southern African coastal systems. Like most seagrasses globally, Z. capensis is declining and under threat from anthropogenic pressures, and indicators of seagrass health and resilience may be of interest in preventing further declines. As intraspecific diversity is an important component of resilience, we used a pooled RADseq approach to generate genome-wide measures of variation across the entire South African distribution of Z. capensis. Using nucleotide diversity, heterozygosity and allelic richness we tested for associations with fine-scale anthropogenic pressure data compiled by the South African National Biodiversity Assessment using generalised linear models. Increased fishing effort, habitat loss, sand mining and a change in estuary flow dynamics were found to play an important role in decreasing nucleotide diversity and expected heterozygosity, most likely due to the loss of less resilient genotypes as a result of direct physical damage or indirect consequences. As the building block for adaptation, nucleotide diversity is particularly important for resilience. Because of this, as well as the fact that nucleotide diversity displayed the most distinct difference between the west and east coast, and responded most strongly to anthropogenic pressures, we suggest that this may be a useful measure for monitoring genetic or genomic variation. As genomic diversity influences resilience and resistance to disturbances, the remaining diversity in South African seagrass beds urgently needs to be conserved through restoration efforts and careful management of pressures.
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Affiliation(s)
- Nikki Leanne Phair
- Evolutionary Genomics Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland, South Africa.
| | - Robert John Toonen
- Hawai'i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai'i at Mānoa, USA.
| | - Ingrid Sally Sigrid Knapp
- Hawai'i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai'i at Mānoa, USA.
| | - Sophie von der Heyden
- Evolutionary Genomics Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland, South Africa.
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Phair NL, Toonen RJ, Knapp I, von der Heyden S. Shared genomic outliers across two divergent population clusters of a highly threatened seagrass. PeerJ 2019; 7:e6806. [PMID: 31106053 PMCID: PMC6497040 DOI: 10.7717/peerj.6806] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 03/18/2019] [Indexed: 12/15/2022] Open
Abstract
The seagrass, Zostera capensis, occurs across a broad stretch of coastline and wide environmental gradients in estuaries and sheltered bays in southern and eastern Africa. Throughout its distribution, habitats are highly threatened and poorly protected, increasing the urgency of assessing the genomic variability of this keystone species. A pooled genomic approach was employed to obtain SNP data and examine neutral genomic variation and to identify potential outlier loci to assess differentiation across 12 populations across the ∼9,600 km distribution of Z. capensis. Results indicate high clonality and low genomic diversity within meadows, which combined with poor protection throughout its range, increases the vulnerability of this seagrass to further declines or local extinction. Shared variation at outlier loci potentially indicates local adaptation to temperature and precipitation gradients, with Isolation-by-Environment significantly contributing towards shaping spatial variation in Z. capensis. Our results indicate the presence of two population clusters, broadly corresponding to populations on the west and east coasts, with the two lineages shaped only by frequency differences of outlier loci. Notably, ensemble modelling of suitable seagrass habitat provides evidence that the clusters are linked to historical climate refugia around the Last Glacial Maxi-mum. Our work suggests a complex evolutionary history of Z. capensis in southern and eastern Africa that will require more effective protection in order to safeguard this important ecosystem engineer into the future.
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Affiliation(s)
- Nikki Leanne Phair
- Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
| | - Robert John Toonen
- Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, Hawai’i, United States of America
| | - Ingrid Knapp
- Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, Hawai’i, United States of America
| | - Sophie von der Heyden
- Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
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