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Blanco M, Sanz N, Pérez-Martín RI, Sotelo CG. Deepening in the understanding of the role of collagen subunits on the differential molecular arrangement of P. glauca and M. merluccius marine collagens. Protein Expr Purif 2023; 212:106356. [PMID: 37604271 DOI: 10.1016/j.pep.2023.106356] [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] [Received: 06/12/2023] [Revised: 07/28/2023] [Accepted: 08/17/2023] [Indexed: 08/23/2023]
Abstract
Decades of extensive efforts on marine collagen extraction and characterization allowed to recognize the unique and excellent characteristics of marine collagen offering advantages over that obtained from terrestrial sources. However, not all marine collagens have the same biochemical characteristics; understanding those at molecular and supramolecular level, is crucial for optimal design of applications. One relevant aspect of collagen characterization is the analysis of its different subunits (α-chains) and their intermolecular cross-links (β- and γ-components), which ultimately determine the specific functions of a particular collagen. Collagens from a teleost and an elasmobranch species were analyzed to understand the influence of their subunit composition and intermolecular crosslinking pattern on their different physicochemical behaviour. For comparative purposes a commercial mammal collagen was included in the study. Although electrophoretic profiles showed the typical composition of type I collagen for hake, blue shark and calf collagen, molar ratios of their α-chains were different indicating a different degree of dimerization of their α2-chains with implications in the presence of a different crosslinking degree pattern. Electrophoresis, amino acid composition, hydrophobicity (RP-HPLC) and molecular weight analysis (GPC-HPLC) results, besides a peptide mapping and an antioxidant activity study of the resultant peptides, would help to understand the role of different subunit collagen composition and different crosslinking pattern in the conformation of a differential quaternary supramolecular structure within different species and its biofunctional implications. The experiments developed would allow to progress in the valorization potential of fish discards and byproducts to explore commercial uses of collagens from marine origin.
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Affiliation(s)
- María Blanco
- Grupo de Bioquímica de alimentos, Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas, Eduardo Cabello, 6, 36208, Vigo, Spain.
| | - Noelia Sanz
- Grupo de Bioquímica de alimentos, Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas, Eduardo Cabello, 6, 36208, Vigo, Spain
| | - Ricardo I Pérez-Martín
- Grupo de Bioquímica de alimentos, Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas, Eduardo Cabello, 6, 36208, Vigo, Spain
| | - Carmen G Sotelo
- Grupo de Bioquímica de alimentos, Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas, Eduardo Cabello, 6, 36208, Vigo, Spain
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2
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Bachar-Wikstrom E, Dhillon B, Gill Dhillon N, Abbo L, Lindén SK, Wikstrom JD. Mass Spectrometry Analysis of Shark Skin Proteins. Int J Mol Sci 2023; 24:16954. [PMID: 38069276 PMCID: PMC10707392 DOI: 10.3390/ijms242316954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/21/2023] [Accepted: 11/24/2023] [Indexed: 12/18/2023] Open
Abstract
The mucus layer covering the skin of fish has several roles, including protection against pathogens and mechanical damage in which proteins play a key role. While proteins in the skin mucus layer of various common bony fish species have been explored, the proteins of shark skin mucus remain unexplored. In this pilot study, we examine the protein composition of the skin mucus in spiny dogfish sharks and chain catsharks through mass spectrometry (NanoLC-MS/MS). Overall, we identified 206 and 72 proteins in spiny dogfish (Squalus acanthias) and chain catsharks (Scyliorhinus retifer), respectively. Categorization showed that the proteins belonged to diverse biological processes and that most proteins were cellular albeit a significant minority were secreted, indicative of mucosal immune roles. The secreted proteins are reviewed in detail with emphasis on their immune potentials. Moreover, STRING protein-protein association network analysis showed that proteins of closely related shark species were more similar as compared to a more distantly related shark and a bony fish, although there were also significant overlaps. This study contributes to the growing field of molecular shark studies and provides a foundation for further research into the functional roles and potential human biomedical implications of shark skin mucus proteins.
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Affiliation(s)
- Etty Bachar-Wikstrom
- Dermatology and Venereology Division, Department of Medicine (Solna), Karolinska Institutet, 17177 Stockholm, Sweden
- Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Braham Dhillon
- Department of Plant Pathology, Fort Lauderdale Research and Education Center, IFAS, University of Florida, Davie, FL 33314, USA
| | - Navi Gill Dhillon
- Department of Biological Sciences, Nova Southeastern University, Davie, FL 33314, USA
| | - Lisa Abbo
- Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Sara K. Lindén
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Jakob D. Wikstrom
- Dermatology and Venereology Division, Department of Medicine (Solna), Karolinska Institutet, 17177 Stockholm, Sweden
- Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA
- Dermato-Venereology Clinic, Karolinska University Hospital, 17176 Stockholm, Sweden
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3
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Characterization of 35 new microsatellite markers for the blacktip reef shark (Carcharhinus melanopterus) and cross-species amplification in eight other shark species. Mol Biol Rep 2023; 50:3205-3215. [PMID: 36707491 DOI: 10.1007/s11033-022-08209-z] [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: 10/09/2022] [Accepted: 12/13/2022] [Indexed: 01/28/2023]
Abstract
BACKGROUND Shark species are overfished at a global scale, as they are poached for the finning industry or are caught as bycatch. Efficient conservation measures require fine-scale spatial and temporal studies to characterize shark habitat use, infer migratory habits, analyze relatedness, and detect population genetic differentiation. Gathering these types of data is costly and time-consuming, especially when it requires collection of shark tissue samples. METHODS AND RESULTS Genetic tools, such as microsatellite markers, are the most economical sampling method for collecting genetic data, as they enable the estimation of genetic diversity, population structure and parentage relationships and are thus an efficient way to inform conservation strategies. Here, a set of 45 microsatellite loci was tested on three blacktip reef shark (Carcharhinus melanopterus) populations from three Polynesian islands: Moorea, Morane and Tenararo. The set was composed of 10 previously published microsatellite markers and 35 microsatellite markers that were developed specifically for C. melanopterus as part of the present study. The 35 novel and 10 existing loci were cross-amplified on eight additional shark species (Carcharhinus amblyrhynchos, C. longimanus, C. sorrah, Galeocerdo cuvier, Negaprion acutidens, Prionacea glauca, Rhincodon typus and Sphyrna lewini). These species had an average of 69% of successful amplification, considered if at least 50% of the individual samples being successfully amplified per species and per locus. CONCLUSIONS This novel microsatellite marker set will help address numerous knowledge gaps that remain, concerning genetic stock identification, shark behavior and reproduction via parentage analysis.
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Bernard AM, Richards VP, Stanhope MJ, Shivji MS. Transcriptome-Derived Microsatellites Demonstrate Strong Genetic Differentiation in Pacific White Sharks. J Hered 2019; 109:771-779. [PMID: 30204894 DOI: 10.1093/jhered/esy045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 09/08/2018] [Indexed: 01/25/2023] Open
Abstract
Recent advances in genome-scale sequencing technology have allowed the development of high resolution genetic markers for the study of nonmodel taxa. In particular, transcriptome sequencing has proven to be highly useful in generating genomic markers for use in population genetic studies, allowing for insight into species connectivity, as well as local adaptive processes as many transcriptome-derived markers are found within or associated with functional genes. Herein, we developed a set of 30 microsatellite markers from a heart transcriptome for the white shark (Carcharodon carcharias), a widely distributed and globally vulnerable marine predator. Using these markers as well as 10 published anonymous genomic microsatellite loci, we provide 1) the first nuclear genetic assessment of the cross-Pacific connectivity of white sharks, and 2) a comparison of the levels of inferred differentiation across microsatellite marker sets (i.e., transcriptome vs. anonymous) to assess their respective utility to elucidate the population genetic dynamics of white sharks. Significant (FST = 0.083, P = 0.05; G″ST = 0.200; P = 0.001) genetic differentiation was found between Southwestern Pacific (n = 19) and Northeastern Pacific (n = 20) white sharks, indicating restricted, cross Pacific gene flow in this species. Transcriptome-derived microsatellite marker sets identified much higher (up to 2×) levels of genetic differentiation than anonymous genomic markers, underscoring potential utility of transcriptome markers in identifying subtle population genetic differences within highly vagile, globally distributed marine species.Subject areas: Population structure and phylogeography; Conservation genetics and biodiversity.
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Affiliation(s)
- Andrea M Bernard
- Save Our Seas Shark Research Center & Guy Harvey Research Institute, Nova Southeastern University, Halmos College of Natural Sciences and Oceanography, North Ocean Drive, Dania Beach, FL
| | - Vincent P Richards
- Department of Biological Sciences, College of Science, Clemson University, Clemson, SC
| | - Michael J Stanhope
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY
| | - Mahmood S Shivji
- Save Our Seas Shark Research Center & Guy Harvey Research Institute, Nova Southeastern University, Halmos College of Natural Sciences and Oceanography, North Ocean Drive, Dania Beach, FL
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5
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Sandoval-Castillo J. Conservation genetics of elasmobranchs of the Mexican Pacific Coast, trends and perspectives. ADVANCES IN MARINE BIOLOGY 2019; 83:115-157. [PMID: 31606069 DOI: 10.1016/bs.amb.2019.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
One of the most critical threats to biodiversity is the high extinction rate driven by human activities. Reducing extinction rates requires the implementation of conservation programmes based on robust scientific data. Elasmobranchs are important ecological components of the ocean, and several species sustain substantial economic activities. Unfortunately, elasmobranchs are one of the most threatened and understudied animal taxa. The Mexican Pacific Coast (MPC) is a region with high elasmobranch diversity and is the seat of major elasmobranch fisheries. But it is also a developing region with several conservation and management challenges which require national and international attention. Here, we review the conservation genetics literature of elasmobranchs from the MPC. We present a synthesis of the works using samples from the region and emphasize the main gaps and biases in these data. In addition, we discuss the benefits and challenges of generating genomic information to improve the management and conservation of an elasmobranch biodiversity hotspot in a developing country. We found 47 elasmobranch genetic articles that cover <30% of the elasmobranch diversity in the region. These studies mainly used mitochondrial DNA sequences to analyse the genetic structure of commercially important and abundant species of the order Carcharhiniformes. Some of these papers also assessed mating systems, demographic parameters, and taxonomic uncertainties, all of which are important topics for efficient management decisions. In terms of conservation genetics, elasmobranchs from the MPC remain understudied. However, high-throughput sequencing technologies have increased the power and accessibility of genomic tools, even in developing countries such as Mexico. The tools described here provide information relevant for biodiversity conservation. Therefore, we strongly suggest that investment in genomic research will assist implementation of efficient management strategies. In time, this will reduce the extinction risk of the unique elasmobranch biodiversity from the MPC.
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Affiliation(s)
- Jonathan Sandoval-Castillo
- Molecular Ecology Lab, College of Science and Engineering, Flinders University, Adelaide, SA, Australia.
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6
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Lyons K, Bigman JS, Kacev D, Mull CG, Carlisle AB, Imhoff JL, Anderson JM, Weng KC, Galloway AS, Cave E, Gunn TR, Lowe CG, Brill RW, Bedore CN. Bridging disciplines to advance elasmobranch conservation: applications of physiological ecology. CONSERVATION PHYSIOLOGY 2019; 7:coz011. [PMID: 31110763 PMCID: PMC6519003 DOI: 10.1093/conphys/coz011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 02/02/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
A strength of physiological ecology is its incorporation of aspects of both species' ecology and physiology; this holistic approach is needed to address current and future anthropogenic stressors affecting elasmobranch fishes that range from overexploitation to the effects of climate change. For example, physiology is one of several key determinants of an organism's ecological niche (along with evolutionary constraints and ecological interactions). The fundamental role of physiology in niche determination led to the development of the field of physiological ecology. This approach considers physiological mechanisms in the context of the environment to understand mechanistic variations that beget ecological trends. Physiological ecology, as an integrative discipline, has recently experienced a resurgence with respect to conservation applications, largely in conjunction with technological advances that extended physiological work from the lab into the natural world. This is of critical importance for species such as elasmobranchs (sharks, skates and rays), which are an especially understudied and threatened group of vertebrates. In 2017, at the American Elasmobranch Society meeting in Austin, Texas, the symposium entitled `Applications of Physiological Ecology in Elasmobranch Research' provided a platform for researchers to showcase work in which ecological questions were examined through a physiological lens. Here, we highlight the research presented at this symposium, which emphasized the strength of linking physiological tools with ecological questions. We also demonstrate the applicability of using physiological ecology research as a method to approach conservation issues, and advocate for a more available framework whereby results are more easily accessible for their implementation into management practices.
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Affiliation(s)
- K Lyons
- Georgia Aquarium, Atlanta, GA, USA
| | - J S Bigman
- Simon Fraser University, Burnaby, Canada
| | - D Kacev
- Southwest Fisheries Science Center, La Jolla, CA, USA
| | - C G Mull
- Simon Fraser University, Burnaby, Canada
| | | | - J L Imhoff
- Florida State University Coastal and Marine Laboratory, St. Teresa, FL, USA
| | - J M Anderson
- University of Hawai`i at Mānoa, Honolulu, HI, USA
| | - K C Weng
- Virginia Institute of Marine Science, Gloucester Point, VA, USA
| | - A S Galloway
- South Carolina Department of Natural Resources, SC, USA
| | - E Cave
- Florida Atlantic University, Boca Raton, FL, USA
| | - T R Gunn
- Georgia Southern University, Statesboro, GA USA
| | - C G Lowe
- California State University Long Beach, Long Beach, CA, USA
| | - R W Brill
- Virginia Institute of Marine Science, Gloucester Point, VA, USA
| | - C N Bedore
- Georgia Southern University, Statesboro, GA USA
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7
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White shark genome reveals ancient elasmobranch adaptations associated with wound healing and the maintenance of genome stability. Proc Natl Acad Sci U S A 2019; 116:4446-4455. [PMID: 30782839 DOI: 10.1073/pnas.1819778116] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The white shark (Carcharodon carcharias; Chondrichthyes, Elasmobranchii) is one of the most publicly recognized marine animals. Here we report the genome sequence of the white shark and comparative evolutionary genomic analyses to the chondrichthyans, whale shark (Elasmobranchii) and elephant shark (Holocephali), as well as various vertebrates. The 4.63-Gbp white shark genome contains 24,520 predicted genes, and has a repeat content of 58.5%. We provide evidence for a history of positive selection and gene-content enrichments regarding important genome stability-related genes and functional categories, particularly so for the two elasmobranchs. We hypothesize that the molecular adaptive emphasis on genome stability in white and whale sharks may reflect the combined selective pressure of large genome sizes, high repeat content, high long-interspersed element retrotransposon representation, large body size, and long lifespans, represented across these two species. Molecular adaptation for wound healing was also evident, with positive selection in key genes involved in the wound-healing process, as well as Gene Ontology enrichments in fundamental wound-healing pathways. Sharks, particularly apex predators such as the white shark, are believed to have an acute sense of smell. However, we found very few olfactory receptor genes, very few trace amine-associated receptors, and extremely low numbers of G protein-coupled receptors. We did however, identify 13 copies of vomeronasal type 2 (V2R) genes in white shark and 10 in whale shark; this, combined with the over 30 V2Rs reported previously for elephant shark, suggests this gene family may underlie the keen odorant reception of chondrichthyans.
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8
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Potential Human Health Applications from Marine Biomedical Research with Elasmobranch Fishes. FISHES 2018. [DOI: 10.3390/fishes3040047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Members of the subclass of fishes collectively known as elasmobranchs (Class Chondrichthyes, Subclass Elasmobranchii) include sharks, skates, rays, guitarfish, and sawfish. Having diverged from the main line of vertebrate evolution some 400 million years ago, these fishes have continued to be successful in our ever-changing oceans. Much of their success must be attributed to their uncanny ability to remain healthy. Based on decades of basic research, some of their secrets may be very close to benefitting man. In this short review, some of the molecular and cellular biological areas that show promise for potential human applications are presented. With a brief background and current status of relevant research, these topics include development of new antibiotics and novel treatments for cancer, macular degeneration, viral pathogens, and Parkinson’s disease; potentially useful genomic information from shark transcriptomes; shark antibody-derived drug delivery systems; and immune cell-derived compounds as potential cancer therapeutic agents.
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Redmond AK, Macqueen DJ, Dooley H. Phylotranscriptomics suggests the jawed vertebrate ancestor could generate diverse helper and regulatory T cell subsets. BMC Evol Biol 2018; 18:169. [PMID: 30442091 PMCID: PMC6238376 DOI: 10.1186/s12862-018-1290-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 11/02/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The cartilaginous fishes diverged from other jawed vertebrates ~ 450 million years ago (mya). Despite this key evolutionary position, the only high-quality cartilaginous fish genome available is for the elephant shark (Callorhinchus milii), a chimaera whose ancestors split from the elasmobranch lineage ~ 420 mya. Initial analysis of this resource led to proposals that key components of the cartilaginous fish adaptive immune system, most notably their array of T cell subsets, was primitive compared to mammals. This proposal is at odds with the robust, antigen-specific antibody responses reported in elasmobranchs following immunization. To explore this discrepancy, we generated a multi-tissue transcriptome for small-spotted catshark (Scyliorhinus canicula), a tractable elasmobranch model for functional studies. We searched this, and other newly available sequence datasets, for CD4+ T cell subset-defining genes, aiming to confirm the presence or absence of each subset in cartilaginous fishes. RESULTS We generated a new transcriptome based on a normalised, multi-tissue RNA pool, aiming to maximise representation of tissue-specific and lowly expressed genes. We utilized multiple transcriptomic datasets and assembly variants in phylogenetic reconstructions to unambiguously identify several T cell subset-specific molecules in cartilaginous fishes for the first time, including interleukins, interleukin receptors, and key transcription factors. Our results reveal the inability of standard phylogenetic reconstruction approaches to capture the site-specific evolutionary processes of fast-evolving immune genes but show that site-heterogeneous mixture models can adequately do so. CONCLUSIONS Our analyses reveal that cartilaginous fishes are capable of producing a range of CD4+ T cell subsets comparable to that of mammals. Further, that the key molecules required for the differentiation and functioning of these subsets existed in the jawed vertebrate ancestor. Additionally, we highlight the importance of considering phylogenetic diversity and, where possible, utilizing multiple datasets for individual species, to accurately infer gene presence or absence at higher taxonomic levels.
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Affiliation(s)
- Anthony K Redmond
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
- Centre for Genome-Enabled Biology & Medicine, University of Aberdeen, Aberdeen, AB24 2TZ, UK
- Present address: Smurfit Institute of Genetics, Trinity College Dublin, University of Dublin, Dublin 2, Ireland
| | - Daniel J Macqueen
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
| | - Helen Dooley
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK.
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Institute of Marine & Environmental Technology, 701 E Pratt St, Baltimore, MD21202, USA.
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11
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Xu Y, Li W, Hu Z, Zeng T, Shen Y, Liu S, Zhang X, Li J, Yue B. Genome-wide mining of perfect microsatellites and tetranucleotide orthologous microsatellites estimates in six primate species. Gene 2017; 643:124-132. [PMID: 29223358 DOI: 10.1016/j.gene.2017.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 12/04/2017] [Accepted: 12/06/2017] [Indexed: 12/16/2022]
Abstract
Advancement in genome sequencing and in silico mining tools have provided new opportunities for comparative primate genomics of microsatellites. The SSRs (simple sequence repeats) numbers were not correlated with the genome size (Pearson, r=0.310, p=0.550), and were positively correlated with the total length of SSRs (Pearson, r=0.992, p=0.00). A total of 224,289 tetranucleotide orthologous microsatellites families and 367 single-copy orthologous SSRs loci were found in six primate species by homologous alignment. The inner mutation types of single-copy orthologous SSRs loci included the copy number variance, point mutation, and chromosomal translocation. The accumulated repeat times and average length of tetranucleotide orthologous microsatellites in Rhinopithecus roxellana, Papio anubis and Macaca mulatta were longer than Homo sapiens and Pan troglodytes, which showed the tetranucleotide orthologous SSRs loci had more repeat times and longer average length on the branches with earlier divergence time, one exception may be Microcebus murinus as a primitive monkey with a smallest morphology in Malagasy. Our conclusion indicated that single-copy tetranucleotide orthologous SSRs sequences accumulated individual mutation more slowly through time in H. sapiens and P. troglodytes than in R. roxellanae, P. anubis and M. mulatta. However, such divergence wouldn't arise uniformly in all branches of the primate tree. A comparison of genomic sequence assemblages would offer remarkable insights about comparisons and contrasts, and the evolutionary processes of the microsatellites involved in human and nonhuman primate species.
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Affiliation(s)
- Yongtao Xu
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu 610064, PR China
| | - Wujiao Li
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu 610064, PR China
| | - Zongxiu Hu
- Yibin Hengshu Animal Models Resource Industry Technology Academy, Yibin 644609, PR China
| | - Tao Zeng
- Yibin Hengshu Animal Models Resource Industry Technology Academy, Yibin 644609, PR China
| | - Yongmei Shen
- Sichuan Engineering Research Center for Medical Animal, Chengdu 610064, PR China
| | - Sanxu Liu
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu 610064, PR China
| | - Xiuyue Zhang
- Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life Sciences, Sichuan University, Chengdu 610064, PR China
| | - Jing Li
- Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life Sciences, Sichuan University, Chengdu 610064, PR China
| | - Bisong Yue
- Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life Sciences, Sichuan University, Chengdu 610064, PR China.
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Multi-tissue RNA-seq and transcriptome characterisation of the spiny dogfish shark (Squalus acanthias) provides a molecular tool for biological research and reveals new genes involved in osmoregulation. PLoS One 2017; 12:e0182756. [PMID: 28832628 PMCID: PMC5568229 DOI: 10.1371/journal.pone.0182756] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/24/2017] [Indexed: 12/29/2022] Open
Abstract
The spiny dogfish shark (Squalus acanthias) is one of the most commonly used cartilaginous fishes in biological research, especially in the fields of nitrogen metabolism, ion transporters and osmoregulation. Nonetheless, transcriptomic data for this organism is scarce. In the present study, a multi-tissue RNA-seq experiment and de novo transcriptome assembly was performed in four different spiny dogfish tissues (brain, liver, kidney and ovary), providing an annotated sequence resource. The characterization of the transcriptome greatly increases the scarce sequence information for shark species. Reads were assembled with the Trinity de novo assembler both within each tissue and across all tissues combined resulting in 362,690 transcripts in the combined assembly which represent 289,515 Trinity genes. BUSCO analysis determined a level of 87% completeness for the combined transcriptome. In total, 123,110 proteins were predicted of which 78,679 and 83,164 had significant hits against the SwissProt and Uniref90 protein databases, respectively. Additionally, 61,215 proteins aligned to known protein domains, 7,208 carried a signal peptide and 15,971 possessed at least one transmembrane region. Based on the annotation, 81,582 transcripts were assigned to gene ontology terms and 42,078 belong to known clusters of orthologous groups (eggNOG). To demonstrate the value of our molecular resource, we show that the improved transcriptome data enhances the current possibilities of osmoregulation research in spiny dogfish by utilizing the novel gene and protein annotations to investigate a set of genes involved in urea synthesis and urea, ammonia and water transport, all of them crucial in osmoregulation. We describe the presence of different gene copies and isoforms of key enzymes involved in this process, including arginases and transporters of urea and ammonia, for which sequence information is currently absent in the databases for this model species. The transcriptome assemblies and the derived annotations generated in this study will support the ongoing research for this particular animal model and provides a new molecular tool to assist biological research in cartilaginous fishes.
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Larson SE, Daly-Engel TS, Phillips NM. Review of Current Conservation Genetic Analyses of Northeast Pacific Sharks. ADVANCES IN MARINE BIOLOGY 2017; 77:79-110. [PMID: 28882215 DOI: 10.1016/bs.amb.2017.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Conservation genetics is an applied science that utilizes molecular tools to help solve problems in species conservation and management. It is an interdisciplinary specialty in which scientists apply the study of genetics in conjunction with traditional ecological fieldwork and other techniques to explore molecular variation, population boundaries, and evolutionary relationships with the goal of enabling resource managers to better protect biodiversity and identify unique populations. Several shark species in the northeast Pacific (NEP) have been studied using conservation genetics techniques, which are discussed here. The primary methods employed to study population genetics of sharks have historically been nuclear microsatellites and mitochondrial (mt) DNA. These markers have been used to assess genetic diversity, mating systems, parentage, relatedness, and genetically distinct populations to inform management decisions. Novel approaches in conservation genetics, including next-generation DNA and RNA sequencing, environmental DNA (eDNA), and epigenetics are just beginning to be applied to elasmobranch evolution, physiology, and ecology. Here, we review the methods and results of past studies, explore future directions for shark conservation genetics, and discuss the implications of molecular research and techniques for the long-term management of shark populations in the NEP.
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Affiliation(s)
| | | | - Nicole M Phillips
- The University of Southern Mississippi, Hattiesburg, MS, United States
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14
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Li Z, Chen F, Huang C, Zheng W, Yu C, Cheng H, Zhou R. Genome-wide mapping and characterization of microsatellites in the swamp eel genome. Sci Rep 2017; 7:3157. [PMID: 28600492 PMCID: PMC5466649 DOI: 10.1038/s41598-017-03330-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/26/2017] [Indexed: 11/09/2022] Open
Abstract
We described genome-wide screening and characterization of microsatellites in the swamp eel genome. A total of 99,293 microsatellite loci were identified in the genome with an overall density of 179 microsatellites per megabase of genomic sequences. The dinucleotide microsatellites were the most abundant type representing 71% of the total microsatellite loci and the AC-rich motifs were the most recurrent in all repeat types. Microsatellite frequency decreased as numbers of repeat units increased, which was more obvious in long than short microsatellite motifs. Most of microsatellites were located in non-coding regions, whereas only approximately 1% of the microsatellites were detected in coding regions. Trinucleotide repeats were most abundant microsatellites in the coding regions, which represented amino acid repeats in proteins. There was a chromosome-biased distribution of microsatellites in non-coding regions, with the highest density of 203.95/Mb on chromosome 8 and the least on chromosome 7 (164.06/Mb). The most abundant dinucleotides (AC)n was mainly located on chromosome 8. Notably, genomic mapping showed that there was a chromosome-biased association of genomic distributions between microsatellites and transposon elements. Thus, the novel dataset of microsatellites in swamp eel provides a valuable resource for further studies on QTL-based selection breeding, genetic resource conservation and evolutionary genetics.
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Affiliation(s)
- Zhigang Li
- Hubei Key Laboratory of Cell Homeostasis, Laboratory of Molecular and Developmental Genetics, College of Life Sciences, Wuhan University, Wuhan, 430072, P. R. China
| | - Feng Chen
- Hubei Key Laboratory of Cell Homeostasis, Laboratory of Molecular and Developmental Genetics, College of Life Sciences, Wuhan University, Wuhan, 430072, P. R. China
| | - Chunhua Huang
- Hubei Key Laboratory of Cell Homeostasis, Laboratory of Molecular and Developmental Genetics, College of Life Sciences, Wuhan University, Wuhan, 430072, P. R. China
| | - Weixin Zheng
- Hubei Key Laboratory of Cell Homeostasis, Laboratory of Molecular and Developmental Genetics, College of Life Sciences, Wuhan University, Wuhan, 430072, P. R. China
| | - Chunlai Yu
- Hubei Key Laboratory of Cell Homeostasis, Laboratory of Molecular and Developmental Genetics, College of Life Sciences, Wuhan University, Wuhan, 430072, P. R. China
| | - Hanhua Cheng
- Hubei Key Laboratory of Cell Homeostasis, Laboratory of Molecular and Developmental Genetics, College of Life Sciences, Wuhan University, Wuhan, 430072, P. R. China.
| | - Rongjia Zhou
- Hubei Key Laboratory of Cell Homeostasis, Laboratory of Molecular and Developmental Genetics, College of Life Sciences, Wuhan University, Wuhan, 430072, P. R. China.
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Marra NJ, Richards VP, Early A, Bogdanowicz SM, Pavinski Bitar PD, Stanhope MJ, Shivji MS. Comparative transcriptomics of elasmobranchs and teleosts highlight important processes in adaptive immunity and regional endothermy. BMC Genomics 2017; 18:87. [PMID: 28132643 PMCID: PMC5278576 DOI: 10.1186/s12864-016-3411-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 12/12/2016] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Comparative genomic and/or transcriptomic analyses involving elasmobranchs remain limited, with genome level comparisons of the elasmobranch immune system to that of higher vertebrates, non-existent. This paper reports a comparative RNA-seq analysis of heart tissue from seven species, including four elasmobranchs and three teleosts, focusing on immunity, but concomitantly seeking to identify genetic similarities shared by the two lamnid sharks and the single billfish in our study, which could be linked to convergent evolution of regional endothermy. RESULTS Across seven species, we identified an average of 10,877 Swiss-Prot annotated genes from an average of 32,474 open reading frames within each species' heart transcriptome. About half of these genes were shared between all species while the remainder included functional differences between our groups of interest (elasmobranch vs. teleost and endotherms vs. ectotherms) as revealed by Gene Ontology (GO) and selection analyses. A repeatedly represented functional category, in both the uniquely expressed elasmobranch genes (total of 259) and the elasmobranch GO enrichment results, involved antibody-mediated immunity, either in the recruitment of immune cells (Fc receptors) or in antigen presentation, including such terms as "antigen processing and presentation of exogenous peptide antigen via MHC class II", and such genes as MHC class II, HLA-DPB1. Molecular adaptation analyses identified three genes in elasmobranchs with a history of positive selection, including legumain (LGMN), a gene with roles in both innate and adaptive immunity including producing antigens for presentation by MHC class II. Comparisons between the endothermic and ectothermic species revealed an enrichment of GO terms associated with cardiac muscle contraction in endotherms, with 19 genes expressed solely in endotherms, several of which have significant roles in lipid and fat metabolism. CONCLUSIONS This collective comparative evidence provides the first multi-taxa transcriptomic-based perspective on differences between elasmobranchs and teleosts, and suggests various unique features associated with the adaptive immune system of elasmobranchs, pointing in particular to the potential importance of MHC Class II. This in turn suggests that expanded comparative work involving additional tissues, as well as genome sequencing of multiple elasmobranch species would be productive in elucidating the regulatory and genome architectural hallmarks of elasmobranchs.
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Affiliation(s)
- Nicholas J Marra
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.,Save Our Seas Shark Research Center and Guy Harvey Research Institute, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, FL, 33004, USA
| | - Vincent P Richards
- Department of Biological Sciences, Clemson University, Clemson, SC, 29634, USA
| | - Angela Early
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Steve M Bogdanowicz
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Paulina D Pavinski Bitar
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Michael J Stanhope
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.
| | - Mahmood S Shivji
- Save Our Seas Shark Research Center and Guy Harvey Research Institute, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, FL, 33004, USA.
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16
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Marra NJ, Wang M, Sun Q, Pavinski Bitar PD, Stanhope MJ, Shivji MS. Mitochondrial genome of an Atlantic white shark ( Carcharodon carcharias). Mitochondrial DNA B Resour 2016; 1:717-719. [PMID: 33473604 PMCID: PMC7799651 DOI: 10.1080/23802359.2016.1222248] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/05/2016] [Indexed: 10/24/2022] Open
Abstract
Here we report the first full mitochondrial genome sequence for a white shark caught in the Atlantic Ocean. The mitochondrial genome is 16,745 bp in length and contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a non-coding control region. The base composition of this mtDNA lineage is A: 30.7%, C: 26.9%, G: 13.8%, and T: 28.6%. In concordance with previous population genetic studies, the Atlantic caught individual forms a separate lineage from individuals caught on either side of the Pacific Ocean.
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Affiliation(s)
- Nicholas J. Marra
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
- Save Our Seas Shark Research Center and Guy Harvey Research Institute, Nova Southeastern University, Dania Beach, FL, USA
| | - Minghui Wang
- Computational Biology Service Unit, Biotechnology Resource Center, Cornell University, Ithaca, NY, USA
| | - Qi Sun
- Computational Biology Service Unit, Biotechnology Resource Center, Cornell University, Ithaca, NY, USA
| | - Paulina D. Pavinski Bitar
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Michael J. Stanhope
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Mahmood S. Shivji
- Save Our Seas Shark Research Center and Guy Harvey Research Institute, Nova Southeastern University, Dania Beach, FL, USA
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17
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Ciezarek AG, Dunning LT, Jones CS, Noble LR, Humble E, Stefanni SS, Savolainen V. Substitutions in the Glycogenin-1 Gene Are Associated with the Evolution of Endothermy in Sharks and Tunas. Genome Biol Evol 2016; 8:3011-3021. [PMID: 27614233 PMCID: PMC5630876 DOI: 10.1093/gbe/evw211] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Despite 400–450 million years of independent evolution, a strong phenotypic convergence has occurred between two groups of fish: tunas and lamnid sharks. This convergence is characterized by centralization of red muscle, a distinctive swimming style (stiffened body powered through tail movements) and elevated body temperature (endothermy). Furthermore, both groups demonstrate elevated white muscle metabolic capacities. All these traits are unusual in fish and more likely evolved to support their fast-swimming, pelagic, predatory behavior. Here, we tested the hypothesis that their convergent evolution was driven by selection on a set of metabolic genes. We sequenced white muscle transcriptomes of six tuna, one mackerel, and three shark species, and supplemented this data set with previously published RNA-seq data. Using 26 species in total (including 7,032 tuna genes plus 1,719 shark genes), we constructed phylogenetic trees and carried out maximum-likelihood analyses of gene selection. We inferred several genes relating to metabolism to be under selection. We also found that the same one gene, glycogenin-1, evolved under positive selection independently in tunas and lamnid sharks, providing evidence of convergent selective pressures at gene level possibly underlying shared physiology.
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Affiliation(s)
- Adam G Ciezarek
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, UK
| | - Luke T Dunning
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, UK Present address: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Catherine S Jones
- Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, Scotland, UK
| | - Leslie R Noble
- Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, Scotland, UK
| | - Emily Humble
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, UK Present address: Department of Animal Behaviour, University of Bielefeld, Postfach 100131, Bielefeld, Germany
| | | | - Vincent Savolainen
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, UK
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18
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Swift DG, Dunning LT, Igea J, Brooks EJ, Jones CS, Noble LR, Ciezarek A, Humble E, Savolainen V. Evidence of positive selection associated with placental loss in tiger sharks. BMC Evol Biol 2016; 16:126. [PMID: 27296413 PMCID: PMC4906603 DOI: 10.1186/s12862-016-0696-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/02/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND All vertebrates initially feed their offspring using yolk reserves. In some live-bearing species these yolk reserves may be supplemented with extra nutrition via a placenta. Sharks belonging to the Carcharhinidae family are all live-bearing, and with the exception of the tiger shark (Galeocerdo cuvier), develop placental connections after exhausting yolk reserves. Phylogenetic relationships suggest the lack of placenta in tiger sharks is due to secondary loss. This represents a dramatic shift in reproductive strategy, and is likely to have left a molecular footprint of positive selection within the genome. RESULTS We sequenced the transcriptome of the tiger shark and eight other live-bearing shark species. From this data we constructed a time-calibrated phylogenetic tree estimating the tiger shark lineage diverged from the placental carcharhinids approximately 94 million years ago. Along the tiger shark lineage, we identified five genes exhibiting a signature of positive selection. Four of these genes have functions likely associated with brain development (YWHAE and ARL6IP5) and sexual reproduction (VAMP4 and TCTEX1D2). CONCLUSIONS Our results indicate the loss of placenta in tiger sharks may be associated with subsequent adaptive changes in brain development and sperm production.
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Affiliation(s)
- Dominic G Swift
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Berkshire, SL5 7PY, UK.
| | - Luke T Dunning
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Javier Igea
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK
| | - Edward J Brooks
- Shark Research & Conservation Program, Cape Eleuthera Institute, PO Box EL - 26029, Eleuthera, the Bahamas
| | - Catherine S Jones
- Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, Scotland, UK
| | - Leslie R Noble
- Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, Scotland, UK
| | - Adam Ciezarek
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Berkshire, SL5 7PY, UK
| | - Emily Humble
- Department of Animal Behaviour, University of Bielefeld, Postfach 100131, 33501, Bielefeld, Germany
| | - Vincent Savolainen
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Berkshire, SL5 7PY, UK.
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19
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Hulsey CD, Fraser GJ, Meyer A. Biting into the Genome to Phenome Map: Developmental Genetic Modularity of Cichlid Fish Dentitions. Integr Comp Biol 2016; 56:373-88. [DOI: 10.1093/icb/icw059] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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20
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Rasch LJ, Martin KJ, Cooper RL, Metscher BD, Underwood CJ, Fraser GJ. An ancient dental gene set governs development and continuous regeneration of teeth in sharks. Dev Biol 2016; 415:347-370. [PMID: 26845577 DOI: 10.1016/j.ydbio.2016.01.038] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/11/2016] [Accepted: 01/29/2016] [Indexed: 12/20/2022]
Abstract
The evolution of oral teeth is considered a major contributor to the overall success of jawed vertebrates. This is especially apparent in cartilaginous fishes including sharks and rays, which develop elaborate arrays of highly specialized teeth, organized in rows and retain the capacity for life-long regeneration. Perpetual regeneration of oral teeth has been either lost or highly reduced in many other lineages including important developmental model species, so cartilaginous fishes are uniquely suited for deep comparative analyses of tooth development and regeneration. Additionally, sharks and rays can offer crucial insights into the characters of the dentition in the ancestor of all jawed vertebrates. Despite this, tooth development and regeneration in chondrichthyans is poorly understood and remains virtually uncharacterized from a developmental genetic standpoint. Using the emerging chondrichthyan model, the catshark (Scyliorhinus spp.), we characterized the expression of genes homologous to those known to be expressed during stages of early dental competence, tooth initiation, morphogenesis, and regeneration in bony vertebrates. We have found that expression patterns of several genes from Hh, Wnt/β-catenin, Bmp and Fgf signalling pathways indicate deep conservation over ~450 million years of tooth development and regeneration. We describe how these genes participate in the initial emergence of the shark dentition and how they are redeployed during regeneration of successive tooth generations. We suggest that at the dawn of the vertebrate lineage, teeth (i) were most likely continuously regenerative structures, and (ii) utilised a core set of genes from members of key developmental signalling pathways that were instrumental in creating a dental legacy redeployed throughout vertebrate evolution. These data lay the foundation for further experimental investigations utilizing the unique regenerative capacity of chondrichthyan models to answer evolutionary, developmental, and regenerative biological questions that are impossible to explore in classical models.
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Affiliation(s)
- Liam J Rasch
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Kyle J Martin
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Rory L Cooper
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Brian D Metscher
- Department of Theoretical Biology, University of Vienna, Vienna A-1090, Austria
| | - Charlie J Underwood
- Department of Earth and Planetary Sciences, Birkbeck, University of London, London WC1E 7HX, United Kingdom
| | - Gareth J Fraser
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom.
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21
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Mulley JF, Hargreaves AD, Hegarty MJ, Heller RS, Swain MT. Transcriptomic analysis of the lesser spotted catshark (Scyliorhinus canicula) pancreas, liver and brain reveals molecular level conservation of vertebrate pancreas function. BMC Genomics 2014; 15:1074. [PMID: 25480530 PMCID: PMC4362833 DOI: 10.1186/1471-2164-15-1074] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 11/27/2014] [Indexed: 12/20/2022] Open
Abstract
Background Understanding the evolution of the vertebrate pancreas is key to understanding its functions. The chondrichthyes (cartilaginous fish such as sharks and rays) have often been suggested to possess the most ancient example of a distinct pancreas with both hormonal (endocrine) and digestive (exocrine) roles. The lack of genetic, genomic and transcriptomic data for cartilaginous fish has hindered a more thorough understanding of the molecular-level functions of the chondrichthyan pancreas, particularly with respect to their “unusual” energy metabolism (where ketone bodies and amino acids are the main oxidative fuel source) and their paradoxical ability to both maintain stable blood glucose levels and tolerate extensive periods of hypoglycemia. In order to shed light on some of these processes, we carried out the first large-scale comparative transcriptomic survey of multiple cartilaginous fish tissues: the pancreas, brain and liver of the lesser spotted catshark, Scyliorhinus canicula. Results We generated a mutli-tissue assembly comprising 86,006 contigs, of which 44,794 were assigned to a particular tissue or combination of tissues based on mapping of sequencing reads. We have characterised transcripts encoding genes involved in insulin regulation, glucose sensing, transcriptional regulation, signaling and digestion, as well as many peptide hormone precursors and their receptors for the first time. Comparisons to mammalian pancreas transcriptomes reveals that mechanisms of glucose sensing and insulin regulation used to establish and maintain a stable internal environment are conserved across jawed vertebrates and likely pre-date the vertebrate radiation. Conservation of pancreatic hormones and genes encoding digestive proteins support the single, early evolution of a distinct pancreatic gland with endocrine and exocrine functions in jawed vertebrates. In addition, we demonstrate that chondrichthyes lack pancreatic polypeptide (PP) and that reports of PP in the literature are likely due cross-reaction with PYY and/or NPY in the pancreas. A three hormone islet organ is therefore the ancestral jawed vertebrate condition, later elaborated upon only in the tetrapod lineage. Conclusions The cartilaginous fish are a great untapped resource for the reconstruction of patterns and processes of vertebrate evolution and new approaches such as those described in this paper will greatly facilitate their incorporation into the rank of “model organism”. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1074) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- John F Mulley
- School of Biological Sciences, Bangor University, Brambell Building, Deiniol Road, Bangor, Gwynedd LL57 2UW, United Kingdom.
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