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Guo Y, Tang J, Zhuo Z, Huang J, Fu Z, Song J, Liu M, Dong Z, Wang Z. The first high-quality chromosome-level genome of Eretmochelys imbricata using HiFi and Hi-C data. Sci Data 2023; 10:604. [PMID: 37689728 PMCID: PMC10492850 DOI: 10.1038/s41597-023-02522-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/30/2023] [Indexed: 09/11/2023] Open
Abstract
Eretmochelys imbricata, a critically endangered sea turtle inhabiting tropical oceans and protected across the world, had an unknown genome sequence until now. In this study, we used HiFi reads and Hi-C technology to assemble a high-quality, chromosome-level genome of E. imbricata. The genome size was 2,138.26 Mb, with contig N50 length of 123.49 Mb and scaffold N50 of 137.21 Mb. Approximately 97.52% of the genome sequence was anchored to 28 chromosomes. A total of 20,206 protein-coding genes were predicted. We also analyzed the evolutionary relationships, gene family expansions, and positive selection of E. imbricata. Our results revealed that E. imbricata diverged from Chelonia mydas 38 million years ago and had enriched olfactory receptors and aging-related genes. Our genome will be useful for studying E. imbricata and its conservation.
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Affiliation(s)
- Yusong Guo
- Key Laboratory of Aquaculture in South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Jiao Tang
- Key Laboratory of Aquaculture in South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Zixuan Zhuo
- Key Laboratory of Aquaculture in South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Jingru Huang
- Key Laboratory of Aquaculture in South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Zhenli Fu
- Key Laboratory of Aquaculture in South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Jiahao Song
- State Key Laboratory of Marine Environmental Science and College of Ocean & Earth Sciences, Xiamen University, Xiamen, Fujian, China
| | - Min Liu
- State Key Laboratory of Marine Environmental Science and College of Ocean & Earth Sciences, Xiamen University, Xiamen, Fujian, China
| | - Zhongdian Dong
- Key Laboratory of Aquaculture in South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Zhongduo Wang
- Key Laboratory of Aquaculture in South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China.
- Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy culture, Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China.
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Tissue and Temperature-Specific RNA-Seq Analysis Reveals Genomic Versatility and Adaptive Potential in Wild Sea Turtle Hatchlings ( Caretta caretta). Animals (Basel) 2021; 11:ani11113013. [PMID: 34827746 PMCID: PMC8614379 DOI: 10.3390/ani11113013] [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: 08/31/2021] [Revised: 09/24/2021] [Accepted: 10/18/2021] [Indexed: 01/05/2023] Open
Abstract
Simple Summary Digital transcriptomics is rapidly emerging as a powerful new technology for modelling the environmental dynamics of the adaptive landscape in diverse lineages. This is particularly valuable in taxa such as turtles and tortoises (order Testudines) which contain a large fraction of endangered species at risk due to anthropogenic impacts on the environment, including pollution, overharvest, habitat degradation, and climate change. Sea turtles (family Cheloniidae) in particular invite a genomics-enabled approach to investigating their remarkable portfolio of adaptive evolution. Our de novo transcriptome assemblies and measurements of tissue- and temperature- specific global gene expression in the loggerhead sea turtle (Caretta caretta) reveal the genomic basis for potential resiliency in this endangered flagship species, and are crucial to future management and conservation strategies with attention to changing climates. We summarize the interactions among differentially expressed genes by producing network visualizations, and highlight the shared biological pathways related to development, migration, immunity, and longevity reported in the avian and reptilian literature. Our original results for loggerhead sea turtles provide a large, new comparative genomic resource for the investigation of genotype–phenotype relationships in amniotes. Abstract Background: Digital transcriptomics is rapidly emerging as a powerful new technology for modelling the environmental dynamics of the adaptive landscape in diverse lineages. This is particularly valuable in taxa such as turtles and tortoises (order Testudines) which contain a large fraction of endangered species at risk due to anthropogenic impacts on the environment, including pollution, overharvest, habitat degradation, and climate change. Sea turtles (family Cheloniidae) in particular invite a genomics-enabled approach to investigating their remarkable portfolio of adaptive evolution. The sex of the endangered loggerhead sea turtle (Caretta caretta) is subject to temperature-dependent sex determination (TSD), a mechanism by which exposure to temperatures during embryonic development irreversibly determines sex. Higher temperatures produce mainly female turtles and lower temperatures produce mainly male turtles. Incubation temperature can have long term effects on the immunity, migratory ability, and ultimately longevity of hatchlings. We perform RNA-seq differential expression analysis to investigate tissue- and temperature-specific gene expression within brain (n = 7) and gonadal (n = 4) tissue of male and female loggerhead hatchlings. Results: We assemble tissue- and temperature-specific transcriptomes and identify differentially expressed genes relevant to sexual development and life history traits of broad adaptive interest to turtles and other amniotic species. We summarize interactions among differentially expressed genes by producing network visualizations, and highlight shared biological pathways related to migration, immunity, and longevity reported in the avian and reptile literature. Conclusions: The measurement of tissue- and temperature-specific global gene expression of an endangered, flagship species such as the loggerhead sea turtle (Caretta caretta) reveals the genomic basis for potential resiliency and is crucial to future management and conservation strategies with attention to changing climates. Brain and gonadal tissue collected from experimentally reared loggerhead male and female hatchlings comprise an exceedingly rare dataset that permits the identification of genes enriched in functions related to sexual development, immunity, longevity, and migratory behavior and will serve as a large, new genomic resource for the investigation of genotype–phenotype relationships in amniotes.
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Álvarez-Varas R, Rojas-Hernández N, Heidemeyer M, Riginos C, Benítez HA, Araya-Donoso R, Reséndiz E, Lara-Uc M, Godoy DA, Muñoz-Pérez JP, Alarcón-Ruales DE, Alfaro-Shigueto J, Ortiz-Alvarez C, Mangel JC, Vianna JA, Véliz D. Green, yellow or black? Genetic differentiation and adaptation signatures in a highly migratory marine turtle. Proc Biol Sci 2021; 288:20210754. [PMID: 34229490 DOI: 10.1098/rspb.2021.0754] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Marine species may exhibit genetic structure accompanied by phenotypic differentiation related to adaptation despite their high mobility. Two shape-based morphotypes have been identified for the green turtle (Chelonia mydas) in the Pacific Ocean: the south-central/western or yellow turtle and north-central/eastern or black turtle. The genetic differentiation between these morphotypes and the adaptation of the black turtle to environmentally contrasting conditions of the eastern Pacific region has remained a mystery for decades. Here we addressed both questions using a reduced-representation genome approach (Dartseq; 9473 neutral SNPs) and identifying candidate outlier loci (67 outlier SNPs) of biological relevance between shape-based morphotypes from eight Pacific foraging grounds (n = 158). Our results support genetic divergence between morphotypes, probably arising from strong natal homing behaviour. Genes and enriched biological functions linked to thermoregulation, hypoxia, melanism, morphogenesis, osmoregulation, diet and reproduction were found to be outliers for differentiation, providing evidence for adaptation of C. mydas to the eastern Pacific region and suggesting independent evolutionary trajectories of the shape-based morphotypes. Our findings support the evolutionary distinctness of the enigmatic black turtle and contribute to the adaptive research and conservation genomics of a long-lived and highly mobile vertebrate.
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Affiliation(s)
- Rocío Álvarez-Varas
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Núcleo Milenio de Ecología y Manejo Sustentable de Islas Oceánicas (ESMOI), Departamento de Biología Marina, Universidad Católica del Norte, Coquimbo, Chile.,Qarapara Tortugas Marinas Chile NGO, Santiago, Chile
| | - Noemi Rojas-Hernández
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Maike Heidemeyer
- Centro de Investigación en Biología Celular y Molecular (CIBCM), Universidad de Costa Rica, San José, Costa Rica
| | - Cynthia Riginos
- School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Hugo A Benítez
- Laboratorio de Ecología y Morfometría Evolutiva, Centro de Investigación de Estudios Avanzados del Maule, Universidad Católica del Maule, Talca, Chile
| | | | - Eduardo Reséndiz
- Departamento Académico de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, Mexico
| | - Mónica Lara-Uc
- Departamento Académico de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, Mexico
| | - Daniel A Godoy
- Coastal-Marine Research Group, Institute of Natural and Mathematical Sciences, Massey University, Auckland, New Zealand
| | - Juan Pablo Muñoz-Pérez
- Galapagos Science Center GSC (Universidad San Francisco de Quito USFQ-University of North Carolina at Chapel Hill UNC), Isla San Cristobal, Galápagos, Ecuador.,University of the Sunshine Coast USC, 90 Sippy Downs Dr, Sippy Downs, Queensland 4556, Australia
| | - Daniela E Alarcón-Ruales
- Galapagos Science Center GSC (Universidad San Francisco de Quito USFQ-University of North Carolina at Chapel Hill UNC), Isla San Cristobal, Galápagos, Ecuador
| | - Joanna Alfaro-Shigueto
- ProDelphinus, Lima, Peru.,Facultad de Biología Marina, Universidad Científica del Perú, Lima, Peru
| | | | | | - Juliana A Vianna
- Departamento de Ecosistemas y Medio Ambiente, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - David Véliz
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Núcleo Milenio de Ecología y Manejo Sustentable de Islas Oceánicas (ESMOI), Departamento de Biología Marina, Universidad Católica del Norte, Coquimbo, Chile
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Maurer AS, Seminoff JA, Layman CA, Stapleton SP, Godfrey MH, Reiskind MOB. Population Viability of Sea Turtles in the Context of Global Warming. Bioscience 2021. [DOI: 10.1093/biosci/biab028] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Sea turtles present a model for the potential impacts of climate change on imperiled species, with projected warming generating concern about their persistence. Various sea turtle life-history traits are affected by temperature; most strikingly, warmer egg incubation temperatures cause female-biased sex ratios and higher embryo mortality. Predictions of sea turtle resilience to climate change are often focused on how resulting male limitation or reduced offspring production may affect populations. In the present article, by reviewing research on sea turtles, we provide an overview of how temperature impacts on incubating eggs may cascade through life history to ultimately affect population viability. We explore how sex-specific patterns in survival and breeding periodicity determine the differences among offspring, adult, and operational sex ratios. We then discuss the implications of skewed sex ratios for male-limited reproduction, consider the negative correlation between sex ratio skew and genetic diversity, and examine consequences for adaptive potential. Our synthesis underscores the importance of considering the effects of climate throughout the life history of any species. Lethal effects (e.g., embryo mortality) are relatively direct impacts, but sublethal effects at immature life-history stages may not alter population growth rates until cohorts reach reproductive maturity. This leaves a lag during which some species transition through several stages subject to distinct biological circumstances and climate impacts. These perspectives will help managers conceptualize the drivers of emergent population dynamics and identify existing knowledge gaps under different scenarios of predicted environmental change.
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Affiliation(s)
- Andrew S Maurer
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, in the United States; he is also a research associate with the Jumby Bay Hawksbill Project in Antigua, West Indies
| | - Jeffrey A Seminoff
- Marine Turtle Ecology and Assessment Program, National Oceanic and Atmospheric Administration's Southwest Fisheries Science Center, La Jolla, California, United States
| | - Craig A Layman
- Center for Energy, Environment, and Sustainability, Wake Forest University, in Winston-Salem, North Carolina, in the United States
| | - Seth P Stapleton
- Conservation and animal health sciences, Minnesota Zoo, Apple Valley, Minnesota; he is also an adjunct faculty member in the Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, in Minneapolis, Minnesota, in the United States
| | - Matthew H Godfrey
- North Carolina Wildlife Resources Commission, Raleigh, North Carolina, United States
| | - Martha O Burford Reiskind
- Martha Burford Reiskind is an assistant professor in the Department of Biological Sciences and the director of the Genetics and Genomics Scholars program, North Carolina State University, Raleigh, North Carolina, United States
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Barbanti A, Torrado H, Macpherson E, Bargelloni L, Franch R, Carreras C, Pascual M. Helping decision making for reliable and cost-effective 2b-RAD sequencing and genotyping analyses in non-model species. Mol Ecol Resour 2020; 20. [PMID: 32061018 DOI: 10.1111/1755-0998.13144] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 02/04/2020] [Accepted: 02/10/2020] [Indexed: 12/18/2022]
Abstract
High-throughput sequencing has revolutionized population and conservation genetics. RAD sequencing methods, such as 2b-RAD, can be used on species lacking a reference genome. However, transferring protocols across taxa can potentially lead to poor results. We tested two different IIB enzymes (AlfI and CspCI) on two species with different genome sizes (the loggerhead turtle Caretta caretta and the sharpsnout seabream Diplodus puntazzo) to build a set of guidelines to improve 2b-RAD protocols on non-model organisms while optimising costs. Good results were obtained even with degraded samples, showing the value of 2b-RAD in studies with poor DNA quality. However, library quality was found to be a critical parameter on the number of reads and loci obtained for genotyping. Resampling analyses with different number of reads per individual showed a trade-off between number of loci and number of reads per sample. The resulting accumulation curves can be used as a tool to calculate the number of sequences per individual needed to reach a mean depth ≥20 reads to acquire good genotyping results. Finally, we demonstrated that selective-base ligation does not affect genomic differentiation between individuals, indicating that this technique can be used in species with large genome sizes to adjust the number of loci to the study scope, to reduce sequencing costs and to maintain suitable sequencing depth for a reliable genotyping without compromising the results. Here, we provide a set of guidelines to improve 2b-RAD protocols on non-model organisms with different genome sizes, helping decision-making for a reliable and cost-effective genotyping.
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Affiliation(s)
- Anna Barbanti
- Department of Genetics, Microbiology and Statistics and IRBio, University of Barcelona, Barcelona, Spain
| | - Hector Torrado
- Department of Genetics, Microbiology and Statistics and IRBio, University of Barcelona, Barcelona, Spain.,Center for Advanced Studies of Blanes (CEAB-CSIC), Blanes, Girona, Spain
| | - Enrique Macpherson
- Center for Advanced Studies of Blanes (CEAB-CSIC), Blanes, Girona, Spain
| | - Luca Bargelloni
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
| | - Rafaella Franch
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
| | - Carlos Carreras
- Department of Genetics, Microbiology and Statistics and IRBio, University of Barcelona, Barcelona, Spain
| | - Marta Pascual
- Department of Genetics, Microbiology and Statistics and IRBio, University of Barcelona, Barcelona, Spain
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