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Calboli FCF, Delahaut V, Deflem I, Hablützel PI, Hellemans B, Kordas A, Raeymaekers JAM, Bervoets L, De Boeck G, Volckaert FAM. Association between Chromosome 4 and mercury accumulation in muscle of the three-spined stickleback ( Gasterosteus aculeatus). Evol Appl 2021; 14:2553-2567. [PMID: 34745343 PMCID: PMC8549617 DOI: 10.1111/eva.13298] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 08/18/2021] [Accepted: 08/29/2021] [Indexed: 11/29/2022] Open
Abstract
Anthropogenic stressors, such as pollutants, act as selective factors that can leave measurable changes in allele frequencies in the genome. Metals are of particular concern among pollutants, because of interference with vital biological pathways. We use the three-spined stickleback as a model for adaptation to mercury pollution in natural populations. We collected sticklebacks from 21 locations in Flanders (Belgium), measured the accumulated levels of mercury in the skeletal muscle tissue, and genotyped the fish by sequencing (GBS). The spread of muscle mercury content across locations was considerable, ranging from 21.5 to 327 ng/g dry weight (DW). We then conducted a genome-wide association study (GWAS) between 28,450 single nucleotide polymorphisms (SNPs) and the accumulated levels of mercury, using different approaches. Based on a linear mixed model analysis, the GWAS yielded multiple hits with a single top hit on Chromosome 4, with eight more SNPs suggestive of association. A second approach, a latent factor mixed model analysis, highlighted one single SNP on Chromosome 11. Finally, an outlier test identified one additional SNP on Chromosome 4 that appeared under selection. Out of all ten SNPs we identified as associated with mercury in muscle, three SNPs all located on Chromosome 4 and positioned within a 2.5 kb distance of an annotated gene. Based on these results and the genome coverage of our SNPs, we conclude that the selective effect of mercury pollution in Flanders causes a significant association with at least one locus on Chromosome 4 in three-spined stickleback.
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Affiliation(s)
- Federico C. F. Calboli
- Laboratory of Biodiversity and Evolutionary GenomicsKU LeuvenLeuvenBelgium
- Present address:
Natural Resources Institute Finland (Luke)HelsinkiFinland
| | - Vyshal Delahaut
- Department of BiologySystemic Physiological and Ecotoxicological Research (SPHERE)University of AntwerpAntwerpenBelgium
| | - Io Deflem
- Laboratory of Biodiversity and Evolutionary GenomicsKU LeuvenLeuvenBelgium
| | | | - Bart Hellemans
- Laboratory of Biodiversity and Evolutionary GenomicsKU LeuvenLeuvenBelgium
| | - Anna Kordas
- Laboratory of Biodiversity and Evolutionary GenomicsKU LeuvenLeuvenBelgium
| | | | - Lieven Bervoets
- Department of BiologySystemic Physiological and Ecotoxicological Research (SPHERE)University of AntwerpAntwerpenBelgium
| | - Gudrun De Boeck
- Department of BiologySystemic Physiological and Ecotoxicological Research (SPHERE)University of AntwerpAntwerpenBelgium
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2
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Christiansen H, Heindler FM, Hellemans B, Jossart Q, Pasotti F, Robert H, Verheye M, Danis B, Kochzius M, Leliaert F, Moreau C, Patel T, Van de Putte AP, Vanreusel A, Volckaert FAM, Schön I. Facilitating population genomics of non-model organisms through optimized experimental design for reduced representation sequencing. BMC Genomics 2021; 22:625. [PMID: 34418978 PMCID: PMC8380342 DOI: 10.1186/s12864-021-07917-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 07/26/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Genome-wide data are invaluable to characterize differentiation and adaptation of natural populations. Reduced representation sequencing (RRS) subsamples a genome repeatedly across many individuals. However, RRS requires careful optimization and fine-tuning to deliver high marker density while being cost-efficient. The number of genomic fragments created through restriction enzyme digestion and the sequencing library setup must match to achieve sufficient sequencing coverage per locus. Here, we present a workflow based on published information and computational and experimental procedures to investigate and streamline the applicability of RRS. RESULTS In an iterative process genome size estimates, restriction enzymes and size selection windows were tested and scaled in six classes of Antarctic animals (Ostracoda, Malacostraca, Bivalvia, Asteroidea, Actinopterygii, Aves). Achieving high marker density would be expensive in amphipods, the malacostracan target taxon, due to the large genome size. We propose alternative approaches such as mitogenome or target capture sequencing for this group. Pilot libraries were sequenced for all other target taxa. Ostracods, bivalves, sea stars, and fish showed overall good coverage and marker numbers for downstream population genomic analyses. In contrast, the bird test library produced low coverage and few polymorphic loci, likely due to degraded DNA. CONCLUSIONS Prior testing and optimization are important to identify which groups are amenable for RRS and where alternative methods may currently offer better cost-benefit ratios. The steps outlined here are easy to follow for other non-model taxa with little genomic resources, thus stimulating efficient resource use for the many pressing research questions in molecular ecology.
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Affiliation(s)
- Henrik Christiansen
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium.
| | - Franz M Heindler
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Bart Hellemans
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Quentin Jossart
- Marine Biology Group, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | | | - Henri Robert
- OD Nature, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Marie Verheye
- OD Nature, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Bruno Danis
- Marine Biology Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Marc Kochzius
- Marine Biology Group, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Frederik Leliaert
- Marine Biology Research Group, Ghent University, Ghent, Belgium.,Meise Botanic Garden, Meise, Belgium
| | - Camille Moreau
- Marine Biology Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium.,Université de Bourgogne Franche-Comté (UBFC) UMR CNRS 6282 Biogéosciences, Dijon, France
| | - Tasnim Patel
- OD Nature, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Anton P Van de Putte
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium.,OD Nature, Royal Belgian Institute of Natural Sciences, Brussels, Belgium.,Marine Biology Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Ann Vanreusel
- Marine Biology Research Group, Ghent University, Ghent, Belgium
| | - Filip A M Volckaert
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Isa Schön
- OD Nature, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
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3
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Martínez P, Robledo D, Taboada X, Blanco A, Moser M, Maroso F, Hermida M, Gómez-Tato A, Álvarez-Blázquez B, Cabaleiro S, Piferrer F, Bouza C, Lien S, Viñas AM. A genome-wide association study, supported by a new chromosome-level genome assembly, suggests sox2 as a main driver of the undifferentiatiated ZZ/ZW sex determination of turbot (Scophthalmus maximus). Genomics 2021; 113:1705-1718. [PMID: 33838278 DOI: 10.1016/j.ygeno.2021.04.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/20/2021] [Accepted: 04/05/2021] [Indexed: 01/10/2023]
Abstract
BACKGROUND Understanding sex determination (SD) across taxa is a major challenge for evolutionary biology. The new genomic tools are paving the way to identify genomic features underlying SD in fish, a group frequently showing limited sex chromosome differentiation and high SD evolutionary turnover. Turbot (Scophthalmus maximus) is a commercially important flatfish with an undifferentiated ZW/ZZ SD system and remarkable sexual dimorphism. Here we describe a new long-read turbot genome assembly used to disentangle the genetic architecture of turbot SD by combining genomics and classical genetics approaches. RESULTS The new turbot genome assembly consists of 145 contigs (N50 = 22.9 Mb), 27 of them representing >95% of its estimated genome size. A genome wide association study (GWAS) identified a ~ 6.8 Mb region on chromosome 12 associated with sex in 69.4% of the 36 families analyzed. The highest associated markers flanked sox2, the only gene in the region showing differential expression between sexes before gonad differentiation. A single SNP showed consistent differences between Z and W chromosomes. The analysis of a broad sample of families suggested the presence of additional genetic and/or environmental factors on turbot SD. CONCLUSIONS The new chromosome-level turbot genome assembly, one of the most contiguous fish assemblies to date, facilitated the identification of sox2 as a consistent candidate gene putatively driving SD in this species. This chromosome SD system barely showed any signs of differentiation, and other factors beyond the main QTL seem to control SD in a certain proportion of families.
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Affiliation(s)
- Paulino Martínez
- Departament of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary, Universidade de Santiago de Compostela, Campus de Lugo, 27002 Lugo, Spain.
| | - Diego Robledo
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK.
| | - Xoana Taboada
- Departament of Zoology, Genetics and Physical Anthropology, Faculty of Biology, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Andrés Blanco
- Departament of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary, Universidade de Santiago de Compostela, Campus de Lugo, 27002 Lugo, Spain.
| | - Michel Moser
- Centre for Integrative Genetics, Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway.
| | - Francesco Maroso
- Department of Life Science and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
| | - Miguel Hermida
- Departament of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary, Universidade de Santiago de Compostela, Campus de Lugo, 27002 Lugo, Spain.
| | - Antonio Gómez-Tato
- Departament of Mathematics, Faculty of Mathematics, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
| | - Blanca Álvarez-Blázquez
- Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Vigo, Cabo Estay-Canido, 36280 Vigo, Spain.
| | - Santiago Cabaleiro
- Cluster de Acuicultura de Galicia (Punta do Couso), Aguiño-Ribeira, 15695 A Coruña, Spain.
| | - Francesc Piferrer
- Institut de Ciències del Mar, Consejo Superior de Investigaciones Científicas (CSIC), 08003 Barcelona, Spain.
| | - Carmen Bouza
- Departament of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary, Universidade de Santiago de Compostela, Campus de Lugo, 27002 Lugo, Spain.
| | - Sigbjørn Lien
- Centre for Integrative Genetics, Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway.
| | - Ana M Viñas
- Departament of Zoology, Genetics and Physical Anthropology, Faculty of Biology, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
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4
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Complementarity and discriminatory power of genotype and otolith shape in describing the fine-scale population structure of an exploited fish, the common sole of the Eastern English Channel. PLoS One 2020; 15:e0241429. [PMID: 33151981 PMCID: PMC7643961 DOI: 10.1371/journal.pone.0241429] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/15/2020] [Indexed: 12/13/2022] Open
Abstract
Marine organisms show population structure at a relatively fine spatial scale, even in open habitats. The tools commonly used to assess subtle patterns of connectivity have diverse levels of resolution and can complement each other to inform on population structure. We assessed and compared the discriminatory power of genetic markers and otolith shape to reveal the population structure on evolutionary and ecological time scales of the common sole (Solea solea), living in the Eastern English Channel (EEC) stock off France and the UK. First, we genotyped fish with Single Nucleotide Polymorphisms to assess population structure at an evolutionary scale. Then, we tested for spatial segregation of the subunits using otolith shape as an integrative tracer of life history. Finally, a supervised machine learning framework was applied to genotypes and otolith phenotypes to probabilistically assign adults to subunits and assess the discriminatory power of each approach. Low but significant genetic differentiation was found among subunits. Moreover, otolith shape appeared to vary spatially, suggesting spatial population structure at fine spatial scale. However, results of the supervised discriminant analyses failed to discriminate among subunits, especially for otolith shape. We suggest that the degree of population segregation may not be strong enough to allow for robust fish assignments. Finally, this study revealed a weak yet existing metapopulation structure of common sole at the fine spatial scale of the EEC based on genotypes and otolith shape, with one subunit being more isolated. Our study argues for the use of complementary tracers to investigate marine population structure.
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5
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Vera M, Pardo BG, Cao A, Vilas R, Fernández C, Blanco A, Gutierrez AP, Bean TP, Houston RD, Villalba A, Martínez P. Signatures of selection for bonamiosis resistance in European flat oyster ( Ostrea edulis): New genomic tools for breeding programs and management of natural resources. Evol Appl 2019; 12:1781-1796. [PMID: 31548857 PMCID: PMC6752124 DOI: 10.1111/eva.12832] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/18/2019] [Accepted: 06/09/2019] [Indexed: 12/18/2022] Open
Abstract
The European flat oyster (Ostrea edulis) is a highly appreciated mollusk with an important aquaculture production throughout the 20th century, in addition to playing an important role on coastal ecosystems. Overexploitation of natural beds, habitat degradation, introduction of non-native species, and epidemic outbreaks have severely affected this important resource, particularly, the protozoan parasite Bonamia ostreae, which is the main concern affecting its production and conservation. In order to identify genomic regions and markers potentially associated with bonamiosis resistance, six oyster beds distributed throughout the European Atlantic coast were sampled. Three of them have been exposed to this parasite since the early 1980s and showed some degree of innate resistance (long-term affected group, LTA), while the other three were free of B. ostreae at least until sampling date (naïve group, NV). A total of 14,065 SNPs were analyzed, including 37 markers from candidate genes and 14,028 from a medium-density SNP array. Gene diversity was similar between LTA and NV groups suggesting no genetic erosion due to long-term exposure to the parasite, and three population clusters were detected using the whole dataset. Tests for divergent selection between NV and LTA groups detected the presence of a very consistent set of 22 markers, located within a putative single genomic region, which suggests the presence of a major quantitative trait locus associated with B. ostreae resistance. Moreover, 324 outlier loci associated with factors other than bonamiosis were identified allowing fully discrimination of all the oyster beds. A practical tool which included the 84 highest discriminative markers for tracing O. edulis populations was developed and tested with empirical data. Results reported herein could assist the production of stocks with improved resistance to bonamiosis and facilitate the management of oyster beds for recovery production and ecosystem services provided by this species.
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Affiliation(s)
- Manuel Vera
- Department of Zoology, Genetics and Physical Anthropology, ACUIGEN group, Faculty of VeterinaryUniversidade de Santiago de CompostelaLugoSpain
- Instituto de AcuiculturaUniversidade de Santiago de CompostelaLugoSpain
| | - Belén G. Pardo
- Department of Zoology, Genetics and Physical Anthropology, ACUIGEN group, Faculty of VeterinaryUniversidade de Santiago de CompostelaLugoSpain
- Instituto de AcuiculturaUniversidade de Santiago de CompostelaLugoSpain
| | - Asunción Cao
- Centro de Investigacións Mariñas (CIMA)Consellería do Mar, Xunta de GaliciaPontevedraSpain
| | - Román Vilas
- Department of Zoology, Genetics and Physical Anthropology, ACUIGEN group, Faculty of VeterinaryUniversidade de Santiago de CompostelaLugoSpain
- Instituto de AcuiculturaUniversidade de Santiago de CompostelaLugoSpain
| | - Carlos Fernández
- Department of Zoology, Genetics and Physical Anthropology, ACUIGEN group, Faculty of VeterinaryUniversidade de Santiago de CompostelaLugoSpain
- Instituto de AcuiculturaUniversidade de Santiago de CompostelaLugoSpain
| | - Andrés Blanco
- Department of Zoology, Genetics and Physical Anthropology, ACUIGEN group, Faculty of VeterinaryUniversidade de Santiago de CompostelaLugoSpain
- Instituto de AcuiculturaUniversidade de Santiago de CompostelaLugoSpain
| | - Alejandro P. Gutierrez
- The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Tim P. Bean
- The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Ross D. Houston
- The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Antonio Villalba
- Centro de Investigacións Mariñas (CIMA)Consellería do Mar, Xunta de GaliciaPontevedraSpain
- Departamento de Ciencias de la VidaUniversidad de AlcaláMadridSpain
- Research Centre for Experimental Marine Biology and Biotechnology (PIE)University of the Basque Country (UPV/EHU)Basque CountrySpain
| | - Paulino Martínez
- Department of Zoology, Genetics and Physical Anthropology, ACUIGEN group, Faculty of VeterinaryUniversidade de Santiago de CompostelaLugoSpain
- Instituto de AcuiculturaUniversidade de Santiago de CompostelaLugoSpain
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6
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Introgressive hybridisation between two widespread sharks in the east Pacific region. Mol Phylogenet Evol 2019; 136:119-127. [DOI: 10.1016/j.ympev.2019.04.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 03/27/2019] [Accepted: 04/10/2019] [Indexed: 11/21/2022]
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7
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Christiansen H, Dettai A, Heindler FM, Collins MA, Duhamel G, Hautecoeur M, Steinke D, Volckaert FAM, Van de Putte AP. Diversity of Mesopelagic Fishes in the Southern Ocean - A Phylogeographic Perspective Using DNA Barcoding. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00120] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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8
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Maroso F, Hermida M, Millán A, Blanco A, Saura M, Fernández A, Dalla Rovere G, Bargelloni L, Cabaleiro S, Villanueva B, Bouza C, Martínez P. Highly dense linkage maps from 31 full-sibling families of turbot (Scophthalmus maximus) provide insights into recombination patterns and chromosome rearrangements throughout a newly refined genome assembly. DNA Res 2018; 25:439-450. [PMID: 29897548 PMCID: PMC6105115 DOI: 10.1093/dnares/dsy015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/05/2018] [Indexed: 12/26/2022] Open
Abstract
Highly dense linkage maps enable positioning thousands of landmarks useful for anchoring the whole genome and for analysing genome properties. Turbot is the most important cultured flatfish worldwide and breeding programs in the fifth generation of selection are targeted to improve growth rate, obtain disease resistant broodstock and understand sex determination to control sex ratio. Using a Restriction-site Associated DNA approach, we genotyped 18,214 single nucleotide polymorphism in 1,268 turbot individuals from 31 full-sibling families. Individual linkage maps were combined to obtain a male, female and species consensus maps. The turbot consensus map contained 11,845 markers distributed across 22 linkage groups representing a total normalised length of 3,753.9 cM. The turbot genome was anchored to this map, and scaffolds representing 96% of the assembly were ordered and oriented to obtain the expected 22 megascaffolds according to its karyotype. Recombination rate was lower in males, especially around centromeres, and pairwise comparison of 44 individual maps suggested chromosome polymorphism at specific genomic regions. Genome comparison across flatfish provided new evidence on karyotype reorganisations occurring across the evolution of this fish group.
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Affiliation(s)
| | - M Hermida
- Departamento de Zoología, Genética y Antropología Física, Facultad de Veterinaria, Universidade de Santiago de Compostela, Lugo, Spain
| | | | - A Blanco
- Departamento de Zoología, Genética y Antropología Física, Facultad de Veterinaria, Universidade de Santiago de Compostela, Lugo, Spain
| | - M Saura
- Departamento de Mejora Genética Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - A Fernández
- Departamento de Mejora Genética Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - G Dalla Rovere
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Padova, Italy
| | - L Bargelloni
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Padova, Italy
| | - S Cabaleiro
- Cluster de Acuicultura de Galicia (Punta do Couso), Aguiño-Ribeira, Spain
| | - B Villanueva
- Departamento de Mejora Genética Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - C Bouza
- Departamento de Zoología, Genética y Antropología Física, Facultad de Veterinaria, Universidade de Santiago de Compostela, Lugo, Spain
| | - P Martínez
- Departamento de Zoología, Genética y Antropología Física, Facultad de Veterinaria, Universidade de Santiago de Compostela, Lugo, Spain
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9
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RAD Sequencing and a Hybrid Antarctic Fur Seal Genome Assembly Reveal Rapidly Decaying Linkage Disequilibrium, Global Population Structure and Evidence for Inbreeding. G3-GENES GENOMES GENETICS 2018; 8:2709-2722. [PMID: 29954843 PMCID: PMC6071602 DOI: 10.1534/g3.118.200171] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recent advances in high throughput sequencing have transformed the study of wild organisms by facilitating the generation of high quality genome assemblies and dense genetic marker datasets. These resources have the potential to significantly advance our understanding of diverse phenomena at the level of species, populations and individuals, ranging from patterns of synteny through rates of linkage disequilibrium (LD) decay and population structure to individual inbreeding. Consequently, we used PacBio sequencing to refine an existing Antarctic fur seal (Arctocephalus gazella) genome assembly and genotyped 83 individuals from six populations using restriction site associated DNA (RAD) sequencing. The resulting hybrid genome comprised 6,169 scaffolds with an N50 of 6.21 Mb and provided clear evidence for the conservation of large chromosomal segments between the fur seal and dog (Canis lupus familiaris). Focusing on the most extensively sampled population of South Georgia, we found that LD decayed rapidly, reaching the background level by around 400 kb, consistent with other vertebrates but at odds with the notion that fur seals experienced a strong historical bottleneck. We also found evidence for population structuring, with four main Antarctic island groups being resolved. Finally, appreciable variance in individual inbreeding could be detected, reflecting the strong polygyny and site fidelity of the species. Overall, our study contributes important resources for future genomic studies of fur seals and other pinnipeds while also providing a clear example of how high throughput sequencing can generate diverse biological insights at multiple levels of organization.
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10
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Maroso F, Hillen JEJ, Pardo BG, Gkagkavouzis K, Coscia I, Hermida M, Franch R, Hellemans B, Van Houdt J, Simionati B, Taggart JB, Nielsen EE, Maes G, Ciavaglia SA, Webster LMI, Volckaert FAM, Martinez P, Bargelloni L, Ogden R. Performance and precision of double digestion RAD (ddRAD) genotyping in large multiplexed datasets of marine fish species. Mar Genomics 2018; 39:64-72. [PMID: 29496460 DOI: 10.1016/j.margen.2018.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 02/19/2018] [Accepted: 02/20/2018] [Indexed: 01/29/2023]
Abstract
The development of Genotyping-By-Sequencing (GBS) technologies enables cost-effective analysis of large numbers of Single Nucleotide Polymorphisms (SNPs), especially in "non-model" species. Nevertheless, as such technologies enter a mature phase, biases and errors inherent to GBS are becoming evident. Here, we evaluated the performance of double digest Restriction enzyme Associated DNA (ddRAD) sequencing in SNP genotyping studies including high number of samples. Datasets of sequence data were generated from three marine teleost species (>5500 samples, >2.5 × 1012 bases in total), using a standardized protocol. A common bioinformatics pipeline based on STACKS was established, with and without the use of a reference genome. We performed analyses throughout the production and analysis of ddRAD data in order to explore (i) the loss of information due to heterogeneous raw read number across samples; (ii) the discrepancy between expected and observed tag length and coverage; (iii) the performances of reference based vs. de novo approaches; (iv) the sources of potential genotyping errors of the library preparation/bioinformatics protocol, by comparing technical replicates. Our results showed use of a reference genome and a posteriori genotype correction improved genotyping precision. Individual read coverage was a key variable for reproducibility; variance in sequencing depth between loci in the same individual was also identified as an important factor and found to correlate to tag length. A comparison of downstream analysis carried out with ddRAD vs single SNP allele specific assay genotypes provided information about the levels of genotyping imprecision that can have a significant impact on allele frequency estimations and population assignment. The results and insights presented here will help to select and improve approaches to the analysis of large datasets based on RAD-like methodologies.
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Affiliation(s)
- F Maroso
- Department of Compared Biomedicine and Food Science, University of Padova, 35020 Legnaro, Italy.
| | - J E J Hillen
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch. de Bériotstraat 32 Box 2439, B-3000 Leuven, Belgium
| | - B G Pardo
- Departmento de Zoología, Genética y Antropología Física, Universidade de Santiago de Compostela, 27002 Lugo, Spain
| | - K Gkagkavouzis
- Department of Genetics, Development & Molecular Biology, School of Biology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - I Coscia
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch. de Bériotstraat 32 Box 2439, B-3000 Leuven, Belgium; School of Environmental and Life Science, Rm 332, Peel Building, University of Salford, Salford M5 4WT, UK
| | - M Hermida
- Departmento de Zoología, Genética y Antropología Física, Universidade de Santiago de Compostela, 27002 Lugo, Spain
| | - R Franch
- Department of Compared Biomedicine and Food Science, University of Padova, 35020 Legnaro, Italy
| | - B Hellemans
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch. de Bériotstraat 32 Box 2439, B-3000 Leuven, Belgium
| | - J Van Houdt
- Department of Human Genetics, University of Leuven, O&N I Herestraat 49 - Box 602, B-3000 Leuven, Belgium
| | - B Simionati
- BMR Genomics, Via Redipuglia 21a, Padova, Italy
| | - J B Taggart
- Division of Environmental and Evolutionary Biology, School of Biology and Biochemistry, The Queen's University of Belfast, Belfast BT7 INN, UK
| | - E E Nielsen
- National Institute of Aquatic Resources, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
| | - G Maes
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch. de Bériotstraat 32 Box 2439, B-3000 Leuven, Belgium; Department of Human Genetics, University of Leuven, O&N I Herestraat 49 - Box 602, B-3000 Leuven, Belgium; Centre for Sustainable Tropical Fisheries and Aquaculture, Comparative Genomics Centre, College of Marine and Environmental Sciences, Faculty of Science and Engineering, James Cook University, Townsville, 4811, QLD, Australia
| | - S A Ciavaglia
- Science and Advice for Scottish Agriculture, Roddinglaw Road, Edinburgh EH12 9FJ, UK
| | - L M I Webster
- Science and Advice for Scottish Agriculture, Roddinglaw Road, Edinburgh EH12 9FJ, UK
| | - F A M Volckaert
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch. de Bériotstraat 32 Box 2439, B-3000 Leuven, Belgium
| | - P Martinez
- Departmento de Zoología, Genética y Antropología Física, Universidade de Santiago de Compostela, 27002 Lugo, Spain
| | - L Bargelloni
- Department of Compared Biomedicine and Food Science, University of Padova, 35020 Legnaro, Italy
| | - R Ogden
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Edinburgh EH25 9RG, UK
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Bourgeois S, Senn H, Kaden J, Taggart JB, Ogden R, Jeffery KJ, Bunnefeld N, Abernethy K, McEwing R. Single-nucleotide polymorphism discovery and panel characterization in the African forest elephant. Ecol Evol 2018; 8:2207-2217. [PMID: 29468037 PMCID: PMC5817121 DOI: 10.1002/ece3.3854] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 12/17/2017] [Accepted: 12/29/2017] [Indexed: 12/14/2022] Open
Abstract
The continuing decline in forest elephant (Loxodonta cyclotis) numbers due to poaching and habitat reduction is driving the search for new tools to inform management and conservation. For dense rainforest species, basic ecological data on populations and threats can be challenging and expensive to collect, impeding conservation action in the field. As such, genetic monitoring is being increasingly implemented to complement or replace more burdensome field techniques. Single-nucleotide polymorphisms (SNPs) are particularly cost-effective and informative markers that can be used for a range of practical applications, including population census, assessment of human impact on social and genetic structure, and investigation of the illegal wildlife trade. SNP resources for elephants are scarce, but next-generation sequencing provides the opportunity for rapid, inexpensive generation of SNP markers in nonmodel species. Here, we sourced forest elephant DNA from 23 samples collected from 10 locations within Gabon, Central Africa, and applied double-digest restriction-site-associated DNA (ddRAD) sequencing to discover 31,851 tags containing SNPs that were reduced to a set of 1,365 high-quality candidate SNP markers. A subset of 115 candidate SNPs was then selected for assay design and validation using 56 additional samples. Genotyping resulted in a high conversion rate (93%) and a low per allele error rate (0.07%). This study provides the first panel of 107 validated SNP markers for forest elephants. This resource presents great potential for new genetic tools to produce reliable data and underpin a step-change in conservation policies for this elusive species.
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Affiliation(s)
- Stéphanie Bourgeois
- Agence Nationale des Parcs NationauxLibrevilleGabon
- WildGenes LaboratoryThe Royal Zoological Society of ScotlandEdinburgh ZooEdinburghUK
- Biological and Environmental SciencesFaculty of Natural SciencesUniversity of StirlingStirlingUK
| | - Helen Senn
- WildGenes LaboratoryThe Royal Zoological Society of ScotlandEdinburgh ZooEdinburghUK
| | - Jenny Kaden
- WildGenes LaboratoryThe Royal Zoological Society of ScotlandEdinburgh ZooEdinburghUK
| | - John B. Taggart
- Aquaculture Pathfoot BuildingUniversity of StirlingStirlingUK
| | - Rob Ogden
- TRACE Wildlife Forensics NetworkEdinburghUK
- Royal (Dick) School of Veterinary Studies & The Roslin InstituteUniversity of EdinburghEdinburghUK
| | - Kathryn J. Jeffery
- Agence Nationale des Parcs NationauxLibrevilleGabon
- Biological and Environmental SciencesFaculty of Natural SciencesUniversity of StirlingStirlingUK
- Institut de Recherche en Écologie TropicaleLibrevilleGabon
| | - Nils Bunnefeld
- Biological and Environmental SciencesFaculty of Natural SciencesUniversity of StirlingStirlingUK
| | - Katharine Abernethy
- Biological and Environmental SciencesFaculty of Natural SciencesUniversity of StirlingStirlingUK
- Institut de Recherche en Écologie TropicaleLibrevilleGabon
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