1
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Freiler MK, Deckard ML, Proffitt MR, Troy Smith G. Differential expression of steroid-related genes across electrosensory brain regions in two sexually dimorphic species of electric knifefish. Gen Comp Endocrinol 2024; 355:114549. [PMID: 38797340 PMCID: PMC11265523 DOI: 10.1016/j.ygcen.2024.114549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 05/29/2024]
Abstract
The production of communication signals can be modulated by hormones acting on the brain regions that regulate these signals. However, less is known about how signal perception is regulated by hormones. The electrocommunication signals of weakly electric fishes are sexually dimorphic, sensitive to hormones, and vary across species. The neural circuits that regulate the production and perception of these signals are also well-characterized, and electric fishes are thus an excellent model to examine the neuroendocrine regulation of sensorimotor mechanisms of communication. We investigated (1) whether steroid-related genes are expressed in sensory brain regions that process communication signals; and (2) whether this expression differs across sexes and species that have different patterns of sexual dimorphism in their signals. Apteronotus leptorhynchus and Apteronotus albifrons produce continuous electric organ discharges (EODs) that are used for communication. Two brain regions, the electrosensory lateral line lobe (ELL) and the dorsal torus semicircularis (TSd), process inputs from electroreceptors to allow fish to detect and discriminate electrocommunication signals. We used qPCR to quantify the expression of genes for two androgen receptors (ar1, ar2), two estrogen receptors (esr1, esr2b), and aromatase (cyp19a1b). Four out of five steroid-related genes were expressed in both sensory brain regions, and their expression often varied between sexes and species. These results suggest that expression of steroid-related genes in the brain may differentially influence how EOD signals are encoded across species and sexes, and that gonadal steroids may coordinately regulate central circuits that control both the production and perception of EODs.
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Affiliation(s)
- Megan K Freiler
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave, Bloomington, IN 47405, United States.
| | - Mikayla L Deckard
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States
| | - Melissa R Proffitt
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave, Bloomington, IN 47405, United States
| | - G Troy Smith
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave, Bloomington, IN 47405, United States
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2
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Singh PP, Reeves GA, Contrepois K, Papsdorf K, Miklas JW, Ellenberger M, Hu CK, Snyder MP, Brunet A. Evolution of diapause in the African turquoise killifish by remodeling the ancient gene regulatory landscape. Cell 2024; 187:3338-3356.e30. [PMID: 38810644 DOI: 10.1016/j.cell.2024.04.048] [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: 11/24/2021] [Revised: 11/30/2023] [Accepted: 04/30/2024] [Indexed: 05/31/2024]
Abstract
Suspended animation states allow organisms to survive extreme environments. The African turquoise killifish has evolved diapause as a form of suspended development to survive a complete drought. However, the mechanisms underlying the evolution of extreme survival states are unknown. To understand diapause evolution, we performed integrative multi-omics (gene expression, chromatin accessibility, and lipidomics) in the embryos of multiple killifish species. We find that diapause evolved by a recent remodeling of regulatory elements at very ancient gene duplicates (paralogs) present in all vertebrates. CRISPR-Cas9-based perturbations identify the transcription factors REST/NRSF and FOXOs as critical for the diapause gene expression program, including genes involved in lipid metabolism. Indeed, diapause shows a distinct lipid profile, with an increase in triglycerides with very-long-chain fatty acids. Our work suggests a mechanism for the evolution of complex adaptations and offers strategies to promote long-term survival by activating suspended animation programs in other species.
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Affiliation(s)
| | - G Adam Reeves
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Kévin Contrepois
- Department of Genetics, Stanford University, Stanford, CA, USA; Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
| | | | - Jason W Miklas
- Department of Genetics, Stanford University, Stanford, CA, USA
| | | | - Chi-Kuo Hu
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Michael P Snyder
- Department of Genetics, Stanford University, Stanford, CA, USA; Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA; Stanford Diabetes Research Center, Stanford University, Stanford, CA, USA
| | - Anne Brunet
- Department of Genetics, Stanford University, Stanford, CA, USA; Glenn Center for the Biology of Aging, Stanford University, Stanford, CA, USA; Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA; Chan Zuckerberg Biohub, San Francisco, San Francisco, CA, USA.
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3
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Saunders AN, Gallant JR. A review of the reproductive biology of mormyroid fishes: An emerging model for biomedical research. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2024; 342:144-163. [PMID: 38361399 DOI: 10.1002/jez.b.23242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 12/13/2023] [Accepted: 01/17/2024] [Indexed: 02/17/2024]
Abstract
Mormyroidea is a superfamily of weakly electric African fishes with great potential as a model in a variety of biomedical research areas including systems neuroscience, muscle cell and craniofacial development, ion channel biophysics, and flagellar/ciliary biology. However, they are currently difficult to breed in the laboratory setting, which is essential for any tractable model organism. As such, there is a need to better understand the reproductive biology of mormyroids to breed them more reliably in the laboratory to effectively use them as a biomedical research model. This review seeks to (1) briefly highlight the biomedically relevant phenotypes of mormyroids and (2) compile information about mormyroid reproduction including sex differences, breeding season, sexual maturity, gonads, gametes, and courtship/spawning behaviors. We also highlight areas of mormyroid reproductive biology that are currently unexplored and/or have the potential for further investigation that may provide insights into more successful mormyroid laboratory breeding methods.
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Affiliation(s)
- Alyssa N Saunders
- Department of Integrative Biology, Michigan State University, East Lansing, Michigan, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, Michigan, USA
| | - Jason R Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, Michigan, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, Michigan, USA
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4
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Hauser FE, Xiao D, Van Nynatten A, Brochu-De Luca KK, Rajakulendran T, Elbassiouny AE, Sivanesan H, Sivananthan P, Crampton WGR, Lovejoy NR. Ecologically mediated differences in electric organ discharge drive evolution in a sodium channel gene in South American electric fishes. Biol Lett 2024; 20:20230480. [PMID: 38412964 PMCID: PMC10898970 DOI: 10.1098/rsbl.2023.0480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 01/29/2024] [Indexed: 02/29/2024] Open
Abstract
Active electroreception-the ability to detect objects and communicate with conspecifics via the detection and generation of electric organ discharges (EODs)-has evolved convergently in several fish lineages. South American electric fishes (Gymnotiformes) are a highly species-rich group, possibly in part due to evolution of an electric organ (EO) that can produce diverse EODs. Neofunctionalization of a voltage-gated sodium channel gene accompanied the evolution of electrogenic tissue from muscle and resulted in a novel gene (scn4aa) uniquely expressed in the EO. Here, we investigate the link between variation in scn4aa and differences in EOD waveform. We combine gymnotiform scn4aa sequences encoding the C-terminus of the Nav1.4a protein, with biogeographic data and EOD recordings to test whether physiological transitions among EOD types accompany differential selection pressures on scn4aa. We found positive selection on scn4aa coincided with shifts in EOD types. Species that evolved in the absence of predators, which likely selected for reduced EOD complexity, exhibited increased scn4aa evolutionary rates. We model mutations in the protein that may underlie changes in protein function and discuss our findings in the context of gymnotiform signalling ecology. Together, this work sheds light on the selective forces underpinning major evolutionary transitions in electric signal production.
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Affiliation(s)
- Frances E. Hauser
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4
| | - Dawn Xiao
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4
| | - Alexander Van Nynatten
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord St, Toronto, Ontario, Canada M5S 3G5
| | - Kristen K. Brochu-De Luca
- Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, USA
- School of Chemistry, Environmental and Life Sciences, University of The Bahamas, Oakes Field Campus, Nassau, New Providence, The Bahamas
| | - Thanara Rajakulendran
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4
| | - Ahmed E. Elbassiouny
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord St, Toronto, Ontario, Canada M5S 3G5
| | - Harunya Sivanesan
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4
| | - Pradeega Sivananthan
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4
| | - William G. R. Crampton
- Department of Biology, University of Central Florida, 4110 Libra Dr, Orlando, FL 32816, USA
| | - Nathan R. Lovejoy
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord St, Toronto, Ontario, Canada M5S 3G5
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St, Toronto, Ontario, Canada M5S 3B2
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5
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Caputi AA. Living life with an electric touch. J Exp Biol 2023; 226:jeb246060. [PMID: 38009325 DOI: 10.1242/jeb.246060] [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] [Indexed: 11/28/2023]
Abstract
The electric organ discharges (EODs) produced by weakly electric fish have long been a source of scientific intrigue and inspiration. The study of these species has contributed to our understanding of the organization of fixed action patterns, as well as enriching general imaging theory by unveiling the dual impact of an agent's actions on the environment and its own sensory system during the imaging process. This Centenary Review firstly compares how weakly electric fish generate species- and sex-specific stereotyped electric fields by considering: (1) peripheral mechanisms, including the geometry, channel repertoire and innervation of the electrogenic units; (2) the organization of the electric organs (EOs); and (3) neural coordination mechanisms. Secondly, the Review discusses the threefold function of the fish-centered electric fields: (1) to generate electric signals that encode the material, geometry and distance of nearby objects, serving as a short-range sensory modality or 'electric touch'; (2) to mark emitter identity and location; and (3) to convey social messages encoded in stereotypical modulations of the electric field that might be considered as species-specific communication symbols. Finally, this Review considers a range of potential research directions that are likely to be productive in the future.
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Affiliation(s)
- Angel Ariel Caputi
- Sistema Nacional de Investigadores - Uruguay, Av. Wilson Ferreira Aldunate 1219, Pando, PC 15600, Uruguay
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6
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Proffitt MR, Liu X, Ortlund EA, Smith GT. Evolution of androgen receptors contributes to species variation in androgenic regulation of communication signals in electric fishes. Mol Cell Endocrinol 2023; 578:112068. [PMID: 37714403 PMCID: PMC10695101 DOI: 10.1016/j.mce.2023.112068] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/31/2023] [Accepted: 09/11/2023] [Indexed: 09/17/2023]
Abstract
Hormones and receptors coevolve to generate species diversity in hormone action. We compared the structure and function of androgen receptors (ARs) across fishes, with a focus on ARs in ghost knifefishes (Apteronotidae). Apteronotids, like many other teleosts, have two ARs (ARα and ARβ). ARβ is largely conserved, whereas ARα sequences vary considerably across species. The ARα ligand binding domain (LBD) has evolved under positive selection, and differences in the LBD across apteronotid species are associated with diversity in androgenic regulation of behavior. The Apteronotus leptorhynchus ARα LBD differs substantially from that of the Apteronotus albifrons ARα or the ancestral AR. Structural modeling and transactivation assays demonstrated that A. leptorhynchus ARα cannot bind androgens. We propose a model whereby relative expression of ARα versus ARβ in the brain, coupled with loss of androgen binding by ARα in A. leptorhynchus might explain reversals in androgenic regulation and sex differences in electrocommunication behavior.
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Affiliation(s)
- Melissa Renee Proffitt
- Department of Biology and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, USA
| | - Xu Liu
- Department of Biochemistry, Emory University, Atlanta, GA, USA
| | - Eric A Ortlund
- Department of Biochemistry, Emory University, Atlanta, GA, USA
| | - G Troy Smith
- Department of Biology and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, USA.
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7
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Carscadden KA, Batstone RT, Hauser FE. Origins and evolution of biological novelty. Biol Rev Camb Philos Soc 2023; 98:1472-1491. [PMID: 37056155 DOI: 10.1111/brv.12963] [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: 01/28/2022] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 04/15/2023]
Abstract
Understanding the origins and impacts of novel traits has been a perennial interest in many realms of ecology and evolutionary biology. Here, we build on previous evolutionary and philosophical treatments of this subject to encompass novelties across biological scales and eco-evolutionary perspectives. By defining novelties as new features at one biological scale that have emergent effects at other biological scales, we incorporate many forms of novelty that have previously been treated in isolation (such as novelty from genetic mutations, new developmental pathways, new morphological features, and new species). Our perspective is based on the fundamental idea that the emergence of a novelty, at any biological scale, depends on its environmental and genetic context. Through this lens, we outline a broad array of generative mechanisms underlying novelty and highlight how genomic tools are transforming our understanding of the origins of novelty. Lastly, we present several case studies to illustrate how novelties across biological scales and systems can be understood based on common mechanisms of change and their environmental and genetic contexts. Specifically, we highlight how gene duplication contributes to the evolution of new complex structures in visual systems; how genetic exchange in symbiosis alters functions of both host and symbiont, resulting in a novel organism; and how hybridisation between species can generate new species with new niches.
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Affiliation(s)
- Kelly A Carscadden
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant St, Boulder, CO, 80309, USA
| | - Rebecca T Batstone
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL, 61801, USA
| | - Frances E Hauser
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, M1C 1A4, Canada
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8
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Losilla M, Gallant JR. Molecular evolution of the ependymin-related gene epdl2 in African weakly electric fish. G3 (BETHESDA, MD.) 2023; 13:6931758. [PMID: 36529459 PMCID: PMC9997568 DOI: 10.1093/g3journal/jkac331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/01/2022] [Accepted: 11/16/2022] [Indexed: 12/23/2022]
Abstract
Gene duplication and subsequent molecular evolution can give rise to taxon-specific gene specializations. In previous work, we found evidence that African weakly electric fish (Mormyridae) may have as many as three copies of the epdl2 gene, and the expression of two epdl2 genes is correlated with electric signal divergence. Epdl2 belongs to the ependymin-related family (EPDR), a functionally diverse family of secretory glycoproteins. In this study, we first describe vertebrate EPDR evolution and then present a detailed evolutionary history of epdl2 in Mormyridae with emphasis on the speciose genus Paramormyrops. Using Sanger sequencing, we confirm three apparently functional epdl2 genes in Paramormyrops kingsleyae. Next, we developed a nanopore-based amplicon sequencing strategy and bioinformatics pipeline to obtain and classify full-length epdl2 gene sequences (N = 34) across Mormyridae. Our phylogenetic analysis proposes three or four epdl2 paralogs dating from early Paramormyrops evolution. Finally, we conducted selection tests which detected positive selection around the duplication events and identified ten sites likely targeted by selection in the resulting paralogs. These sites' locations in our modeled 3D protein structure involve four sites in ligand binding and six sites in homodimer formation. Together, these findings strongly imply an evolutionary mechanism whereby epdl2 genes underwent selection-driven functional specialization after tandem duplications in the rapidly speciating Paramormyrops. Considering previous evidence, we propose that epdl2 may contribute to electric signal diversification in mormyrids, an important aspect of species recognition during mating.
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Affiliation(s)
- Mauricio Losilla
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA.,Graduate Program in Ecology, Evolution and Behavior, Michigan State University, East Lansing, MI 48824, USA
| | - Jason R Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA.,Graduate Program in Ecology, Evolution and Behavior, Michigan State University, East Lansing, MI 48824, USA
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9
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Roberts RJV, Pop S, Prieto-Godino LL. Evolution of central neural circuits: state of the art and perspectives. Nat Rev Neurosci 2022; 23:725-743. [DOI: 10.1038/s41583-022-00644-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2022] [Indexed: 11/09/2022]
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10
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LaPotin S, Swartz ME, Luecke DM, Constantinou SJ, Gallant JR, Eberhart JK, Zakon HH. Divergent cis-regulatory evolution underlies the convergent loss of sodium channel expression in electric fish. SCIENCE ADVANCES 2022; 8:eabm2970. [PMID: 35648851 PMCID: PMC9159570 DOI: 10.1126/sciadv.abm2970] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
South American and African weakly electric fish independently evolved electric organs from muscle. In both groups, a voltage-gated sodium channel gene independently lost expression from muscle and gained it in the electric organ, allowing the channel to become specialized for generating electric signals. It is unknown how this voltage-gated sodium channel gene is targeted to muscle in any vertebrate. We describe an enhancer that selectively targets sodium channel expression to muscle. Next, we demonstrate how the loss of this enhancer, but not trans-activating factors, drove the loss of sodium channel gene expression from muscle in South American electric fish. While this enhancer is also altered in African electric fish, key transcription factor binding sites and enhancer activity are retained, suggesting that the convergent loss of sodium channel expression from muscle in these two electric fish lineages occurred via different processes.
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Affiliation(s)
- Sarah LaPotin
- Department of Neuroscience, The University of Texas, Austin, TX 78712, USA
| | - Mary E. Swartz
- Department of Molecular Biosciences, The University of Texas, Austin, TX 78712, USA
| | - David M. Luecke
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Savvas J. Constantinou
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
| | - Jason R. Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
| | - Johann K. Eberhart
- Department of Molecular Biosciences, The University of Texas, Austin, TX 78712, USA
| | - Harold H. Zakon
- Department of Neuroscience, The University of Texas, Austin, TX 78712, USA
- Department of Integrative Biology, The University of Texas, Austin, TX 78712, USA
- Corresponding author.
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11
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Bray IE, Alshami IJJ, Kudoh T. The diversity and evolution of electric organs in Neotropical knifefishes. EvoDevo 2022; 13:9. [PMID: 35365204 PMCID: PMC8973549 DOI: 10.1186/s13227-022-00194-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 02/28/2022] [Indexed: 12/03/2022] Open
Abstract
The Gymnotiformes, also known as the South American or Neotropical knifefishes, include the strongly electric Electrophorus electricus and many other weakly electric species. These fish possess specialised electric organs that are able to release electric discharges into the water, for electrolocation and communication, and sometimes for predation and defence. All Gymnotiform species possess a myogenic electric organ (mEO) derived from the muscle tissue, and members of the Apteronotidae family uniquely possess a neurogenic electric organ (nEOs) derived from the nervous tissue. A mEO may consist of ‘Type A’ electrocytes that develop within the tail muscle (for example, in Apteronotus leptorhynchus), or ‘Type B’ electrocytes that develop below the tail muscle (for example, in Brachyhypopomus gauderio). In this review, we discuss the diversity in the anatomy, electric discharge and development of electric organs found in different Gymnotiform species, as well as the ecological and environmental factors that have likely contributed to this diversity. We then describe various hypotheses regarding the evolution of electric organs, and discuss the potential evolutionary origin of the nEO: a pair of nerve cords that are located on either side of the aorta in B. gauderio, and which may have expanded and developed into a nEO in the Apteronotidae family during its evolution from a common ancestral species. Finally, we compare potential Gymnotiform phylogenies and their supporting evidence.
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Affiliation(s)
- Isabelle E Bray
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Ilham J J Alshami
- Department of Fisheries and Marine Resources, College of Agriculture, University of Basrah, Basrah, Iraq
| | - Tetsuhiro Kudoh
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.
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12
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Khan S, Shrotriya S, Sadhukhan S, Lyngdoh S, Goyal SP, Habib B. Comparative Ecological Perspectives of Two Ancient Lineages of Gray Wolves: Woolly Wolf (Canis lupus chanco) and Indian Wolf (Canis lupus pallipes). Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.775612] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Geographical isolation can often lead to speciation, and two disconnected populations of the same species living in drastically different bioclimatic regions provide an opportunity to understand the process of speciation. The Woolly wolf is found in the cold-arid, Trans-Himalayan landscape, while the Indian wolf inhabits the semi-arid grasslands of Central India. Both the lineages of wolves from India have generated scientific debate on their taxonomic status in recent years. In this study, we collected data and reviewed published literature to document the ecological and behavioral differences between the Woolly wolf and the Indian wolf. Most studies have used genetic data; hence we discuss variation in spatial ecology, habitat preferences, vocalization, diet diversity and cranial measurements of these two subspecies. The spatial ecology of two lineages was compared from the data on three Woolly and ten Indian wolves tagged with GPS collars. The telemetry data shows that there has been no difference in the day-night movement of Woolly wolves, whereas Indian wolves show significant high displacement during the night. The BBMM method indicated that Woolly wolf home ranges were three times larger than the Indian wolf. The Woolly wolf diet is comprised of 20 different types of food items, whereas the Indian wolf diet consists of 17 types. The Woolly and Indian wolf largely depend upon domestic prey base, i.e., 48.44 and 40.34%, respectively. We found no differences in the howling parameters of these subspecies. Moreover, the Woolly wolf skull was significantly longer and broader than the Indian wolf. Wolves of India are ancient and diverged from the main clade about 200,000–1,000,000 years ago. Their genetic and ecological evolution in different bioclimatic zones has resulted in considerable differences as distinct subspecies. The present study is a step in understanding ecological differences between two important, genetically unique subspecies of wolves.
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13
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Beck EA, Healey HM, Small CM, Currey MC, Desvignes T, Cresko WA, Postlethwait JH. Advancing human disease research with fish evolutionary mutant models. Trends Genet 2022; 38:22-44. [PMID: 34334238 PMCID: PMC8678158 DOI: 10.1016/j.tig.2021.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 01/03/2023]
Abstract
Model organism research is essential to understand disease mechanisms. However, laboratory-induced genetic models can lack genetic variation and often fail to mimic the spectrum of disease severity. Evolutionary mutant models (EMMs) are species with evolved phenotypes that mimic human disease. EMMs complement traditional laboratory models by providing unique avenues to study gene-by-environment interactions, modular mutations in noncoding regions, and their evolved compensations. EMMs have improved our understanding of complex diseases, including cancer, diabetes, and aging, and illuminated mechanisms in many organs. Rapid advancements of sequencing and genome-editing technologies have catapulted the utility of EMMs, particularly in fish. Fish are the most diverse group of vertebrates, exhibiting a kaleidoscope of specialized phenotypes, many that would be pathogenic in humans but are adaptive in the species' specialized habitat. Importantly, evolved compensations can suggest avenues for novel disease therapies. This review summarizes current research using fish EMMs to advance our understanding of human disease.
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Affiliation(s)
- Emily A Beck
- Data Science, University of Oregon, Eugene, OR 97403, USA; Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA.
| | - Hope M Healey
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Clayton M Small
- Data Science, University of Oregon, Eugene, OR 97403, USA; Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Mark C Currey
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Thomas Desvignes
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - William A Cresko
- Data Science, University of Oregon, Eugene, OR 97403, USA; Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
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14
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OUP accepted manuscript. Zool J Linn Soc 2022. [DOI: 10.1093/zoolinnean/zlac039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Arias CF, Dikow RB, McMillan WO, De León LF. De Novo Genome Assembly of the Electric Fish Brachyhypopomus occidentalis (Hypopomidae, Gymnotiformes). Genome Biol Evol 2021; 13:6377337. [PMID: 34581791 PMCID: PMC8536545 DOI: 10.1093/gbe/evab223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2021] [Indexed: 11/20/2022] Open
Abstract
The bluntnose knifefish Brachyhypopomus occidentalis is a primary freshwater fish from north-western South America and Lower Central America. Like other Gymnotiformes, it has an electric organ that generates electric discharges used for both communication and electrolocation. We assembled a high-quality reference genome sequence of B. occidentalis by combining Oxford Nanopore and 10X Genomics linked-reads technologies. We also describe its demographic history in the context of the rise of the Isthmus of Panama. The size of the assembled genome is 540.3 Mb with an N50 scaffold length of 5.4 Mb, which includes 93.8% complete, 0.7% fragmented, and 5.5% of missing vertebrate/Actinoterigie Benchmarking Universal Single-Copy Orthologs. Repetitive elements account for 11.04% of the genome, and 34,347 protein-coding genes were predicted, of which 23,935 have been functionally annotated. Demographic analysis suggests a rapid effective population expansion between 3 and 5 Myr, corresponding to the final closure of the Isthmus of Panama (2.8–3.5 Myr). This event was followed by a sudden and constant population decline during the last 1 Myr, likely associated with strong shifts in both precipitation and sea level during the Pleistocene glacial-interglacial cycles. The de novo genome assembly of B. occidentalis will provide novel insights into the molecular basis of both electric signal productions and detection and will be fundamental for understanding the processes that have shaped the diversity of Neotropical freshwater environments.
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Affiliation(s)
- Carlos F Arias
- Department of Biology, University of Massachusetts, Boston, Massachusetts, USA.,Data Science Lab, Office of the Chief Information Officer, Smithsonian Institution, Washington, District of Columbia, USA.,Smithsonian Tropical Research Institute, Panamá, Panamá
| | - Rebecca B Dikow
- Data Science Lab, Office of the Chief Information Officer, Smithsonian Institution, Washington, District of Columbia, USA
| | | | - Luis F De León
- Department of Biology, University of Massachusetts, Boston, Massachusetts, USA.,Smithsonian Tropical Research Institute, Panamá, Panamá.,Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT-AIP), Panamá, Panamá
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16
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Dunlap KD, Koukos HM, Chagnaud BP, Zakon HH, Bass AH. Vocal and Electric Fish: Revisiting a Comparison of Two Teleost Models in the Neuroethology of Social Behavior. Front Neural Circuits 2021; 15:713105. [PMID: 34489647 PMCID: PMC8418312 DOI: 10.3389/fncir.2021.713105] [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: 05/21/2021] [Accepted: 07/12/2021] [Indexed: 11/30/2022] Open
Abstract
The communication behaviors of vocal fish and electric fish are among the vertebrate social behaviors best understood at the level of neural circuits. Both forms of signaling rely on midbrain inputs to hindbrain pattern generators that activate peripheral effectors (sonic muscles and electrocytes) to produce pulsatile signals that are modulated by frequency/repetition rate, amplitude and call duration. To generate signals that vary by sex, male phenotype, and social context, these circuits are responsive to a wide range of hormones and neuromodulators acting on different timescales at multiple loci. Bass and Zakon (2005) reviewed the behavioral neuroendocrinology of these two teleost groups, comparing how the regulation of their communication systems have both converged and diverged during their parallel evolution. Here, we revisit this comparison and review the complementary developments over the past 16 years. We (a) summarize recent work that expands our knowledge of the neural circuits underlying these two communication systems, (b) review parallel studies on the action of neuromodulators (e.g., serotonin, AVT, melatonin), brain steroidogenesis (via aromatase), and social stimuli on the output of these circuits, (c) highlight recent transcriptomic studies that illustrate how contemporary molecular methods have elucidated the genetic regulation of social behavior in these fish, and (d) describe recent studies of mochokid catfish, which use both vocal and electric communication, and that use both vocal and electric communication and consider how these two systems are spliced together in the same species. Finally, we offer avenues for future research to further probe how similarities and differences between these two communication systems emerge over ontogeny and evolution.
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Affiliation(s)
- Kent D Dunlap
- Department of Biology, Trinity College, Hartford, CT, United States
| | - Haley M Koukos
- Department of Biology, Trinity College, Hartford, CT, United States
| | - Boris P Chagnaud
- Institute of Biology, Karl-Franzens-University Graz, Graz, Austria
| | - Harold H Zakon
- Department of Neuroscience, University of Texas at Austin, Austin, TX, United States.,Department of Integrative Biology, University of Texas at Austin, Austin, TX, United States
| | - Andrew H Bass
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, United States
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17
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Wang Y, Yang L. Genomic Evidence for Convergent Molecular Adaptation in Electric Fishes. Genome Biol Evol 2021; 13:6151746. [PMID: 33638979 PMCID: PMC7952227 DOI: 10.1093/gbe/evab038] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2021] [Indexed: 12/13/2022] Open
Abstract
Fishes have independently evolved electric organs (EOs) at least six times, and the electric fields are used for communication, defense, and predation. However, the genetic basis of convergent evolution of EOs remains unclear. In this study, we conducted comparative genomic analyses to detect genes showing signatures of positive selection and convergent substitutions in electric fishes from three independent lineages (Mormyroidea, Siluriformes, and Gymnotiformes). Analysis of 4,657 orthologs between electric fishes and their corresponding control groups identified consistent evidence for accelerated evolution in electric fish lineages. A total of 702 positively selected genes (PSGs) were identified in electric fishes, and many of these genes corresponded to cell membrane structure, ion channels, and transmembrane transporter activity. Comparative genomic analyses revealed that widespread convergent amino acid substitutions occurred along the electric fish lineages. The overlap of convergent genes and PSGs was identified as adaptive convergence, and a subset of genes was putatively associated with electrical and muscular activities, especially scn4aa (a voltage-gated sodium channel gene). Our results provide hints to the genetic basis for the independent evolution of EOs during millions of years of evolution.
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Affiliation(s)
- Ying Wang
- College of Life Sciences, Jianghan University, Wuhan, 430056, China
| | - Liandong Yang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
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18
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A comparative genomic database of skeletogenesis genes: from fish to mammals. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2021; 38:100796. [PMID: 33676152 DOI: 10.1016/j.cbd.2021.100796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/19/2021] [Accepted: 01/23/2021] [Indexed: 11/20/2022]
Abstract
Skeletogenesis is a complex process that requires a rigorous control at multiple levels during osteogenesis, such as signaling pathways and transcription factors. The skeleton among vertebrates is a highly conserved organ system, but teleost fish and mammals have evolved unique traits or have lost particular skeletal elements in each lineage. In present study, we constructed a skeletogenesis database containing 4101, 3715, 2996, 3300, 3719 and 3737 genes in Danio rerio, Oryzias latipes, Gallus gallus, Xenopus tropicalis, Mus musculus and Homo sapiens genome, respectively. Then, we found over 55% of the genes are conserved in the six species. Notably, there are 181 specific-genes in the human genome without orthologues in the other five genomes, such as the ZNF family (ZNF100, ZNF101, ZNF14, CALML6, CCL4L2, ZIM2, HSPA6, etc); and 31 genes are identified explicitly in fish species, which are mainly involved in TGF-beta, Wnt, MAPK, Calcium signaling pathways, such as bmp16, bmpr2a, eif4e1c, wnt2ba, etc. Particularly, there are 20 zebrafish-specific genes (calm3a, si:dkey-25li10, drd1a, drd7, etc) and one medaka-specific gene (c-myc17) that may alter skeletogenesis formation in the corresponding species. The database provides the new systematic genomic insights into skeletal development from teleosts to mammals, which may help to explain some of the complexities of skeletal phenotypes among different vertebrates and provide a reference for the treatment of skeletal diseases as well as for applications in the aquaculture industry.
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19
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Broder ED, Elias DO, Rodríguez RL, Rosenthal GG, Seymoure BM, Tinghitella RM. Evolutionary novelty in communication between the sexes. Biol Lett 2021; 17:20200733. [PMID: 33529546 PMCID: PMC8086948 DOI: 10.1098/rsbl.2020.0733] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/11/2021] [Indexed: 12/18/2022] Open
Abstract
The diversity of signalling traits within and across taxa is vast and striking, prompting us to consider how novelty evolves in the context of animal communication. Sexual selection contributes to diversification, and here we endeavour to understand the initial conditions that facilitate the maintenance or elimination of new sexual signals and receiver features. New sender and receiver variants can occur through mutation, plasticity, hybridization and cultural innovation, and the initial conditions of the sender, the receiver and the environment then dictate whether a novel cue becomes a signal. New features may arise in the sender, the receiver or both simultaneously. We contend that it may be easier than assumed to evolve new sexual signals because sexual signals may be arbitrary, sexual conflict is common and receivers are capable of perceiving much more of the world than just existing sexual signals. Additionally, changes in the signalling environment can approximate both signal and receiver changes through a change in transmission characteristics of a given environment or the use of new environments. The Anthropocene has led to wide-scale disruption of the environment and may thus generate opportunity to directly observe the evolution of new signals to address questions that are beyond the reach of phylogenetic approaches.
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Affiliation(s)
- E. Dale Broder
- Department of Biology, St Ambrose University, Davenport, IA 52803, USA
| | - Damian O. Elias
- Department of Environmental Science, Policy and Management, UC Berkeley, Berkeley, CA 94720, USA
| | - Rafael L. Rodríguez
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
| | - Gil G. Rosenthal
- Department of Biology, Texas A&M, College Station, TX 77843, USA
| | - Brett M. Seymoure
- Living Earth Collaborative, Washington University in St. Louis, St. Louis, MO 63130, USA
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20
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Kéver L, Parmentier E, Bass AH, Chagnaud BP. Morphological diversity of acoustic and electric communication systems of mochokid catfish. J Comp Neurol 2020; 529:1787-1809. [PMID: 33070328 PMCID: PMC8048963 DOI: 10.1002/cne.25057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/13/2020] [Accepted: 10/13/2020] [Indexed: 02/06/2023]
Abstract
Mochokid catfish offer a distinct opportunity to study a communication system transitioning to a new signaling channel because some produce sounds and others electric discharges. Both signals are generated using an elastic spring system (ESS), which includes a protractor muscle innervated by motoneurons within the protractor nucleus that also has a motoneuron afferent population. Synodontis grandiops and S. nigriventris produce sounds and electric discharges, respectively, and their ESSs show several morphological and physiological differences. The extent to which these differences explain different signal types remains unclear. Here, we compare ESS morphologies and behavioral phenotypes among five mochokids. S. grandiops and S. nigriventris were compared with Synodontis eupterus that is known to produce both signal types, and representative members of two sister genera, Microsynodontis cf. batesii and Mochokiella paynei, for which no data were available. We provide support for the hypothesis that peripheral and central components of the ESS are conserved among mochokids. We also show that the two nonsynodontids are only sonic, consistent with sound production being an ancestral character for mochokids. Even though the three sound producing‐only species differ in some ESS characters, several are similar and likely associated with only sound production. We propose that the ability of S. eupterus to generate both electric discharges and sounds may depend on a protractor muscle intermediate in morphology between sound producing‐only and electric discharge‐only species, and two separate populations of protractor motoneurons. Our results further suggest that an electrogenic ESS in synodontids is an exaptation of a sound producing ESS.
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Affiliation(s)
- Loïc Kéver
- Laboratoire de Morphologie Fonctionnelle et Evolutive, Université de Liège, Liège, Belgium
| | - Eric Parmentier
- Laboratoire de Morphologie Fonctionnelle et Evolutive, Université de Liège, Liège, Belgium
| | - Andrew H Bass
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, USA
| | - Boris P Chagnaud
- Institute for Biology, Karl-Franzens University Graz, Graz, Austria
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21
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Lei Y, Yang L, Jiang H, Chen J, Sun N, Lv W, He S. Recent genome duplications facilitate the phenotypic diversity of Hb repertoire in the Cyprinidae. SCIENCE CHINA-LIFE SCIENCES 2020; 64:1149-1164. [PMID: 33051703 DOI: 10.1007/s11427-020-1809-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/28/2020] [Indexed: 12/11/2022]
Abstract
Whole-genome duplications (WGDs) are an important contributor to phenotypic innovations in evolutionary history. The diversity of blood oxygen transport traits is the perfect reflection of physiological versatility for evolutionary success among vertebrates. In this study, the evolutionary changes of hemoglobin (Hb) repertoire driven by the recent genome duplications were detected in representative Cyprinidae fish, including eight diploid and four tetraploid species. Comparative genomic analysis revealed a substantial variation in both membership composition and intragenomic organization of Hb genes in these species. Phylogenetic reconstruction analyses were conducted to characterize the evolutionary history of these genes. Data were integrated with the expression profiles of the genes during ontogeny. Our results indicated that genome duplications facilitated the phenotypic diversity of the Hb gene family; each was associated with species-specific changes in gene content via gene loss and fusion after genome duplications. This led to repeated evolutionary transitions in the ontogenic regulation of Hb gene expression. Our results revealed that genome duplications helped to generate phenotypic changes in Cyprinidae Hb systems.
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Affiliation(s)
- Yi Lei
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Liandong Yang
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Haifeng Jiang
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Juan Chen
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ning Sun
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenqi Lv
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shunping He
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China. .,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, 650223, China.
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22
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Li L, Liu D, Liu A, Li J, Wang H, Zhou J. Genomic Survey of Tyrosine Kinases Repertoire in Electrophorus electricus With an Emphasis on Evolutionary Conservation and Diversification. Evol Bioinform Online 2020; 16:1176934320922519. [PMID: 32546936 PMCID: PMC7249569 DOI: 10.1177/1176934320922519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/07/2020] [Indexed: 12/05/2022] Open
Abstract
Tyrosine kinases (TKs) play key roles in the regulation of multicellularity in
organisms and involved primarily in cell growth, differentiation, and
cell-to-cell communication. Genome-wide characterization of TKs has been
conducted in many metazoans; however, systematic information regarding this
superfamily in Electrophorus electricus (electric eel) is still
lacking. In this study, we identified 114 TK genes in the E
electricus genome and investigated their evolution, molecular
features, and domain architecture using phylogenetic profiling to gain a better
understanding of their similarities and specificity. Our results suggested that
the electric eel TK (EeTK) repertoire was shaped by whole-genome duplications
(WGDs) and tandem duplication events. Compared with other vertebrate TKs, gene
members in Jak, Src, and EGFR subfamily duplicated specifically, but with
members lost in Eph, Axl, and Ack subfamily in electric eel. We also conducted
an exhaustive survey of TK genes in genomic databases, identifying 1674 TK
proteins in 31 representative species covering all the main metazoan lineages.
Extensive evolutionary analysis indicated that TK repertoire in vertebrates
tended to be remarkably conserved, but the gene members in each subfamily were
very variable. Comparative expression profile analysis showed that electric
organ tissues and muscle shared a similar pattern with specific highly expressed
TKs (ie, epha7, musk, jak1, and pdgfra), suggesting that regulation of TKs might
play an important role in specifying an electric organ identity from its muscle
precursor. We further identified TK genes exhibiting tissue-specific expression
patterns, indicating that members in TKs participated in subfunctionalization
representing an evolutionary divergence required for the performance of
different tissues. This work generates valuable information for further gene
function analysis and identifying candidate TK genes reflecting their unique
tissue-function specializations in electric eel.
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Affiliation(s)
- Ling Li
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
| | - Dangyun Liu
- Department of Central Laboratory, The Affiliated Huaian No.1 People's Hospital, Nanjing Medical University, Huai'an, P.R. China
| | - Ake Liu
- Faculty of Biological Science and Technology, Changzhi University, Changzhi, P.R. China
| | - Jingquan Li
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
| | - Hui Wang
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
| | - Jingqi Zhou
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
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23
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Picq S, Sperling J, Cheng CJ, Carlson BA, Gallant JR. Genetic drift does not sufficiently explain patterns of electric signal variation among populations of the mormyrid electric fish Paramormyrops kingsleyae. Evolution 2020; 74:911-935. [PMID: 32187650 PMCID: PMC7816287 DOI: 10.1111/evo.13953] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 02/13/2020] [Accepted: 02/20/2020] [Indexed: 11/28/2022]
Abstract
Communication signals serve crucial survival and reproductive functions. In Gabon, the widely distributed mormyrid fish Paramormyrops kingsleyae emits an electric organ discharge (EOD) signal with a dual role in communication and electrolocation that exhibits remarkable variation: populations of P. kingsleyae have either biphasic or triphasic EODs, a feature that characterizes interspecific signal diversity among the Paramormyrops genus. We quantified variation in EODs of 327 P. kingsleyae from nine populations and compared it to genetic variation estimated from microsatellite loci. We found no correlation between electric signal and genetic distances, suggesting that EOD divergence cannot be explained by drift alone. An alternative hypothesis is that EOD differences are used for mate discrimination, which would require P. kingsleyae be capable of differentiating between divergent EOD waveforms. Using a habituation-dishabituation assay, we found that P. kingsleyae can discriminate between biphasic and triphasic EOD types. Nonetheless, patterns of genetic and electric organ morphology divergence provide evidence for hybridization between these signal types. Although reproductive isolation with respect to signal type is incomplete, our results suggest that EOD variation in P. kingsleyae could be a cue for assortative mating.
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Affiliation(s)
- Sophie Picq
- Michigan State University Department of Integrative Biology, East Lansing MI 48824 USA
| | - Joshua Sperling
- Cornell University Department of Neurobiology and Behavior, Ithaca NY 14853 USA
| | - Catherine J. Cheng
- Cornell University Department of Neurobiology and Behavior, Ithaca NY 14853 USA
| | - Bruce A. Carlson
- Washington University in St. Louis Department of Biology, St. Louis, MO 63130 USA
| | - Jason R. Gallant
- Michigan State University Department of Integrative Biology, East Lansing MI 48824 USA
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24
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Abstract
Neuroscience has a long, rich history in embracing unusual animals for research. Over the past several decades, there has been a technology-driven bottleneck in the species used for neuroscience research. However, an oncoming wave of technologies applicable to many animals hold promise for enabling researchers to address challenging scientific questions that cannot be solved using traditional laboratory animals. Here, we discuss how leveraging the convergent evolution of physiological or behavioral phenotypes can empower research mapping genotype to phenotype interactions. We present two case studies using electric fish and poison frogs and discuss how comparative work can teach us about evolutionary constraint and flexibility at various levels of biological organization. We also offer advice on the potential and pitfalls of establishing novel model systems in neuroscience research. Finally, we end with a discussion on the use of charismatic animals in neuroscience research and their utility in public outreach. Overall, we argue that convergent evolution frameworks can help identify generalizable principles of neuroscience.
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Affiliation(s)
- Jason R Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
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25
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Losilla M, Luecke DM, Gallant JR. The transcriptional correlates of divergent electric organ discharges in Paramormyrops electric fish. BMC Evol Biol 2020; 20:6. [PMID: 31918666 PMCID: PMC6953315 DOI: 10.1186/s12862-019-1572-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 12/24/2019] [Indexed: 01/10/2023] Open
Abstract
Background Understanding the genomic basis of phenotypic diversity can be greatly facilitated by examining adaptive radiations with hypervariable traits. In this study, we focus on a rapidly diverged species group of mormyrid electric fish in the genus Paramormyrops, which are characterized by extensive phenotypic variation in electric organ discharges (EODs). The main components of EOD diversity are waveform duration, complexity and polarity. Using an RNA-sequencing based approach, we sought to identify gene expression correlates for each of these EOD waveform features by comparing 11 specimens of Paramormyrops that exhibit variation in these features. Results Patterns of gene expression among Paramormyrops are highly correlated, and 3274 genes (16%) were differentially expressed. Using our most restrictive criteria, we detected 145–183 differentially expressed genes correlated with each EOD feature, with little overlap between them. The predicted functions of several of these genes are related to extracellular matrix, cation homeostasis, lipid metabolism, and cytoskeletal and sarcomeric proteins. These genes are of significant interest given the known morphological differences between electric organs that underlie differences in the EOD waveform features studied. Conclusions In this study, we identified plausible candidate genes that may contribute to phenotypic differences in EOD waveforms among a rapidly diverged group of mormyrid electric fish. These genes may be important targets of selection in the evolution of species-specific differences in mate-recognition signals.
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Affiliation(s)
- Mauricio Losilla
- Department of Integrative Biology, Michigan State University, East Lansing, MI, 48824, USA.,Graduate Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, MI, 48824, USA
| | - David Michael Luecke
- Department of Integrative Biology, Michigan State University, East Lansing, MI, 48824, USA.,Graduate Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, MI, 48824, USA
| | - Jason R Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, MI, 48824, USA. .,Graduate Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, MI, 48824, USA.
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26
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Liu A, He F, Zhou J, Zou Y, Su Z, Gu X. Comparative Transcriptome Analyses Reveal the Role of Conserved Function in Electric Organ Convergence Across Electric Fishes. Front Genet 2019; 10:664. [PMID: 31379927 PMCID: PMC6657706 DOI: 10.3389/fgene.2019.00664] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 06/25/2019] [Indexed: 11/24/2022] Open
Abstract
The independent origins of multiple electric organs (EOs) of fish are fascinating examples of convergent evolution. However, comparative transcriptomics of different electric fish lineages are scarce. In this study, we found that the gene expression of EOs and skeletal muscles from three lineages (Mormyroidea, Siluriformes, and Gymnotiformes) tended to cluster together based on the species of origin, irrespective of the organ from which they are derived. A pairwise comparison of differentially expressed genes (DEGs) revealed that no less than half of shared DEGs exhibited parallel expression differentiation, indicating conserved directionality of differential expression either in or between lineages, but only a few shared DEGs were identified across all focal species. Nevertheless, the functional enrichment analysis of DEGs indicated that there were more parallel gene expression changes at the level of pathways and biological functions. Therefore, we may conclude that there is no parallel evolution of the entire transcriptomes of EOs among different lineages. Further, our results support the hypothesis that it is not different genes but conserved biological functions that play a crucial role in the convergence of complex phenotypes. This study provides insight into the genetic basis underlying the EO convergent evolution; however, more studies in different cases will be needed to demonstrate whether this pattern can be extended to other cases to derive a general rule for convergent evolution.
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Affiliation(s)
- Ake Liu
- Faculty of Biology Sciences and Technology, Changzhi University, Changzhi, China.,School of Life Sciences, Fudan University, Shanghai, China
| | - Funan He
- School of Life Sciences, Fudan University, Shanghai, China
| | - Jingqi Zhou
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yangyun Zou
- School of Life Sciences, Fudan University, Shanghai, China
| | - Zhixi Su
- School of Life Sciences, Fudan University, Shanghai, China.,Singlera Genomics Inc., Shanghai, China
| | - Xun Gu
- Department of GDC Biology, Iowa State University, Ames, IA, United States.,Fudan Human Phenome Institute, Shanghai, China
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27
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Crampton WGR. Electroreception, electrogenesis and electric signal evolution. JOURNAL OF FISH BIOLOGY 2019; 95:92-134. [PMID: 30729523 DOI: 10.1111/jfb.13922] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 02/05/2019] [Indexed: 05/06/2023]
Abstract
Electroreception, the capacity to detect external underwater electric fields with specialised receptors, is a phylogenetically widespread sensory modality in fishes and amphibians. In passive electroreception, a capacity possessed by c. 16% of fish species, an animal uses low-frequency-tuned ampullary electroreceptors to detect microvolt-range bioelectric fields from prey, without the need to generate its own electric field. In active electroreception (electrolocation), which occurs only in the teleost lineages Mormyroidea and Gymnotiformes, an animal senses its surroundings by generating a weak (< 1 V) electric-organ discharge (EOD) and detecting distortions in the EOD-associated field using high-frequency-tuned tuberous electroreceptors. Tuberous electroreceptors also detect the EODs of neighbouring fishes, facilitating electrocommunication. Several other groups of elasmobranchs and teleosts generate weak (< 10 V) or strong (> 50 V) EODs that facilitate communication or predation, but not electrolocation. Approximately 1.5% of fish species possess electric organs. This review has two aims. First, to synthesise our knowledge of the functional biology and phylogenetic distribution of electroreception and electrogenesis in fishes, with a focus on freshwater taxa and with emphasis on the proximate (morphological, physiological and genetic) bases of EOD and electroreceptor diversity. Second, to describe the diversity, biogeography, ecology and electric signal diversity of the mormyroids and gymnotiforms and to explore the ultimate (evolutionary) bases of signal and receptor diversity in their convergent electrogenic-electrosensory systems. Four sets of potential drivers or moderators of signal diversity are discussed. First, selective forces of an abiotic (environmental) nature for optimal electrolocation and communication performance of the EOD. Second, selective forces of a biotic nature targeting the communication function of the EOD, including sexual selection, reproductive interference from syntopic heterospecifics and selection from eavesdropping predators. Third, non-adaptive drift and, finally, phylogenetic inertia, which may arise from stabilising selection for optimal signal-receptor matching.
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Hoke KL, Adkins-Regan E, Bass AH, McCune AR, Wolfner MF. Co-opting evo-devo concepts for new insights into mechanisms of behavioural diversity. ACTA ACUST UNITED AC 2019; 222:222/8/jeb190058. [PMID: 30988051 DOI: 10.1242/jeb.190058] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We propose that insights from the field of evolutionary developmental biology (or 'evo-devo') provide a framework for an integrated understanding of the origins of behavioural diversity and its underlying mechanisms. Towards that goal, in this Commentary, we frame key questions in behavioural evolution in terms of molecular, cellular and network-level properties with a focus on the nervous system. In this way, we highlight how mechanistic properties central to evo-devo analyses - such as weak linkage, versatility, exploratory mechanisms, criticality, degeneracy, redundancy and modularity - affect neural circuit function and hence the range of behavioural variation that can be filtered by selection. We outline why comparative studies of molecular and neural systems throughout ontogeny will provide novel insights into diversity in neural circuits and behaviour.
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Affiliation(s)
- Kim L Hoke
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Elizabeth Adkins-Regan
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA.,Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Andrew H Bass
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Amy R McCune
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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29
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A novel protein domain in an ancestral splicing factor drove the evolution of neural microexons. Nat Ecol Evol 2019; 3:691-701. [DOI: 10.1038/s41559-019-0813-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 01/16/2019] [Indexed: 02/02/2023]
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Aguilar C, Miller MJ, Loaiza JR, Krahe R, De León LF. Mitogenomics of Central American weakly-electric fishes. Gene 2019; 686:164-170. [PMID: 30453071 DOI: 10.1016/j.gene.2018.11.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 11/05/2018] [Accepted: 11/15/2018] [Indexed: 11/20/2022]
Abstract
Electric fishes are a diverse group of freshwater organisms with the ability to generate electric organ discharges (EODs) that are used for communication and electrolocation. This group (ca. 200 species) has originated in South America, and six species colonized the Central American Isthmus. Here, we assembled the complete mitochondrial genomes (mitogenomes) for three Central American electric fishes (i.e. Sternopygus dariensis, Brachyhypopomus occidentalis, and Apteronotus rostratus), and, based on these data, explored their phylogenetic position among Gymnotiformes. The three mitogenomes show the same gene order, as reported for other fishes, with a size ranging from 16,631 to 17,093 bp. We uncovered a novel 60 bp intergenic spacer (IGS) located between the COII and tRNALys genes, which appears to be unique to the Apteronotidae. Furthermore, phylogenetic relationships supported the traditional monophyly of Gymnotiformes, with the three species positioned within their respective family. In addition, the genus Apteronotus belongs to the early diverging lineage of the order. Finally, we found high sequence divergence (13%) between our B. occidentalis specimen and a sequence previously reported in GenBank, suggesting that the prior mitogenome of B. occidentalis represents a different South American species. Indeed, phylogenetic analyses using Cytochrome b gene across the genus placed the previously reported individual within B. bennetti. Our study provides novel mitogenome resources that will advance our understanding of the diversity and phylogenetic history of Neotropical fishes.
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Affiliation(s)
- Celestino Aguilar
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), P. O. Box 0843-01103, Panama, Panama; Department of Biotechnology, Acharya Nagarjuna University, Guntur, India; Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Balboa Ancón, Panama, Panama
| | - Matthew J Miller
- Sam Noble Oklahoma Museum of Natural History and Department of Biology, University of Oklahoma, Norman, OK, USA
| | - Jose R Loaiza
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), P. O. Box 0843-01103, Panama, Panama; Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Balboa Ancón, Panama, Panama
| | - Rüdiger Krahe
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Luis F De León
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), P. O. Box 0843-01103, Panama, Panama; Department of Biology, University of Massachusetts Boston, Boston, MA, USA.
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A Likely Ancient Genome Duplication in the Speciose Reef-Building Coral Genus, Acropora. iScience 2019; 13:20-32. [PMID: 30798090 PMCID: PMC6389592 DOI: 10.1016/j.isci.2019.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 01/28/2019] [Accepted: 01/31/2019] [Indexed: 12/22/2022] Open
Abstract
Whole-genome duplication (WGD) has been recognized as a significant evolutionary force in the origin and diversification of multiple organisms. Acropora, a speciose reef-building coral genus, is suspected to have originated by polyploidy. Yet, there is no genetic evidence to support this hypothesis. Using comprehensive phylogenomic and comparative genomic approaches, we analyzed six Acroporid genomes and found that a WGD event likely occurred ∼31 million years ago in the most recent common ancestor of Acropora, concurrent with a worldwide coral extinction. We found that duplicated genes were highly enriched in gene regulation functions, including those of stress responses. The functional clusters of duplicated genes are related to the divergence of gene expression patterns during development. Some proteinaceous toxins were generated by WGD in Acropora compared with other cnidarian species. Collectively, this study provides evidence for an ancient WGD event in corals, which helps explain the origin and diversification of Acropora. An ancient genome duplication occurred in the most recent common ancestor of Acropora This WGD event likely occurred between 28 and 36 mya in Acropora The WGD event potentially contributes to the origin and diversification of Acropora Duplications of toxic proteins were found in Acropora following the WGD
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Alda F, Tagliacollo VA, Bernt MJ, Waltz BT, Ludt WB, Faircloth BC, Alfaro ME, Albert JS, Chakrabarty P. Resolving Deep Nodes in an Ancient Radiation of Neotropical Fishes in the Presence of Conflicting Signals from Incomplete Lineage Sorting. Syst Biol 2018; 68:573-593. [DOI: 10.1093/sysbio/syy085] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 12/13/2022] Open
Affiliation(s)
- Fernando Alda
- Museum of Natural Science, Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
- Department of Biology, Geology and Environmental Science, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA
| | - Victor A Tagliacollo
- Museu de Zoologia da Universidade de São Paulo (MZUSP), Ipirianga, 04263-000, São Paulo, São Paulo, Brazil
| | - Maxwell J Bernt
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70503, USA
| | - Brandon T Waltz
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70503, USA
| | - William B Ludt
- Museum of Natural Science, Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Brant C Faircloth
- Museum of Natural Science, Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Michael E Alfaro
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - James S Albert
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70503, USA
| | - Prosanta Chakrabarty
- Museum of Natural Science, Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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33
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Chen JN, Samadi S, Chen WJ. Rhodopsin gene evolution in early teleost fishes. PLoS One 2018; 13:e0206918. [PMID: 30395593 PMCID: PMC6218077 DOI: 10.1371/journal.pone.0206918] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 10/22/2018] [Indexed: 01/03/2023] Open
Abstract
Rhodopsin mediates an essential step in image capture and is tightly associated with visual adaptations of aquatic organisms, especially species that live in dim light environments (e.g., the deep sea). The rh1 gene encoding rhodopsin was formerly considered a single-copy gene in genomes of vertebrates, but increasing exceptional cases have been found in teleost fish species. The main objective of this study was to determine to what extent the visual adaptation of teleosts might have been shaped by the duplication and loss of rh1 genes. For that purpose, homologous rh1/rh1-like sequences in genomes of ray-finned fishes from a wide taxonomic range were explored using a PCR-based method, data mining of public genetic/genomic databases, and subsequent phylogenomic analyses of the retrieved sequences. We show that a second copy of the fish-specific intron-less rh1 is present in the genomes of most anguillids (Elopomorpha), Hiodon alosoides (Osteoglossomorpha), and several clupeocephalan lineages. The phylogenetic analysis and comparisons of alternative scenarios for putative events of gene duplication and loss suggested that fish rh1 was likely duplicated twice during the early evolutionary history of teleosts, with one event coinciding with the hypothesized fish-specific genome duplication and the other in the common ancestor of the Clupeocephala. After these gene duplication events, duplicated genes were maintained in several teleost lineages, whereas some were secondarily lost in specific lineages. Alternative evolutionary schemes of rh1 and comparison with previous studies of gene evolution are also reviewed.
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Affiliation(s)
- Jhen-Nien Chen
- Institute of Oceanography, National Taiwan University, Taipei, Taiwan
| | - Sarah Samadi
- Institute de Systématique, Évolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle–CNRS, Sorbonne Université, EPHE, Paris, France
| | - Wei-Jen Chen
- Institute of Oceanography, National Taiwan University, Taipei, Taiwan
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34
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Swapna I, Ghezzi A, York JM, Markham MR, Halling DB, Lu Y, Gallant JR, Zakon HH. Electrostatic Tuning of a Potassium Channel in Electric Fish. Curr Biol 2018; 28:2094-2102.e5. [PMID: 29937349 PMCID: PMC6067922 DOI: 10.1016/j.cub.2018.05.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 04/03/2018] [Accepted: 05/03/2018] [Indexed: 12/21/2022]
Abstract
Molecular variation contributes to the evolution of adaptive phenotypes, though it is often difficult to understand precisely how. The adaptively significant electric organ discharge behavior of weakly electric fish is the direct result of biophysical membrane properties set by ion channels. Here, we describe a voltage-gated potassium-channel gene in African electric fishes that is under positive selection and highly expressed in the electric organ. The channel produced by this gene shortens electric organ action potentials by activating quickly and at hyperpolarized membrane potentials. The source of these properties is a derived patch of negatively charged amino acids in an extracellular loop near the voltage sensor. We demonstrate that this negative patch acts by contributing to the global surface charge rather than by local interactions with specific amino acids in the channel's extracellular face. We suggest a more widespread role for this loop in the evolutionary tuning of voltage-dependent channels.
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Affiliation(s)
- Immani Swapna
- Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA; Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Alfredo Ghezzi
- Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA; Department of Biology, University of Puerto Rico - Rio Piedras, San Juan, PR 00931, USA
| | - Julia M York
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Michael R Markham
- Department of Biology, The University of Oklahoma, Norman, OK 73019, USA
| | - D Brent Halling
- Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ying Lu
- Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jason R Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48864, USA.
| | - Harold H Zakon
- Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA; Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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35
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Gracheva EO, Bagriantsev SN. Communication: Potassium Channels Define the Dialect. Curr Biol 2018; 28:R744-R746. [DOI: 10.1016/j.cub.2018.05.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Genetic and developmental origins of a unique foraging adaptation in a Lake Malawi cichlid genus. Proc Natl Acad Sci U S A 2018; 115:7063-7068. [PMID: 29915062 PMCID: PMC6142203 DOI: 10.1073/pnas.1719798115] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Biologists have long been captivated by novel traits because they provide insights into both the origin of and constraints on morphological variation. The iconic adaptive radiations of cichlid fishes have led to incredible diversity of form, including some species with an exaggerated snout. This novelty is mechanically integrated with the upper jaw, appears to be under directional selection, and is found in one of the most ecologically successful cichlid lineages. We used protein manipulation, gene expression, and genetic mapping to implicate the Tgfβ pathway in the development of this unusual trait. Given the functions of Tgfβ signaling in tissue proliferation, migration, invasion, and organ fibrosis, this represents an example of the cooption of existing pathways in the evolution of novelty. Phenotypic novelties are an important but poorly understood category of morphological diversity. They can provide insights into the origins of phenotypic variation, but we know relatively little about their genetic origins. Cichlid fishes display remarkable diversity in craniofacial anatomy, including several novelties. One aspect of this variation is a conspicuous, exaggerated snout that has evolved in a single Malawi cichlid lineage and is associated with foraging specialization and increased ecological success. We examined the developmental and genetic origins for this phenotype and found that the snout is composed of two hypertrophied tissues: the intermaxillary ligament (IML), which connects the right and left sides of the upper jaw, and the overlying loose connective tissue. The IML is present in all cichlids, but in its exaggerated form it interdigitates with the more superficial connective tissue and anchors to the epithelium, forming a unique ligament–epithelial complex. We examined the Transforming growth factor β (Tgfβ) → Scleraxis (Scx) candidate pathway and confirmed a role for these factors in snout development. We demonstrate further that experimental up-regulation of Tgfβ is sufficient to produce an expansion of scx expression and concomitant changes in snout morphology. Genetic and genomic mapping show that core members of canonical Tgfβ signaling segregate with quantitative trait loci (QTL) for snout variation. These data also implicate a candidate for ligament development, adam12, which we confirm using the zebrafish model. Collectively, these data provide insights into ligament morphogenesis, as well as how an ecologically relevant novelty can arise at the molecular level.
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37
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Thompson A, Infield DT, Smith AR, Smith GT, Ahern CA, Zakon HH. Rapid evolution of a voltage-gated sodium channel gene in a lineage of electric fish leads to a persistent sodium current. PLoS Biol 2018; 16:e2004892. [PMID: 29584718 PMCID: PMC5870949 DOI: 10.1371/journal.pbio.2004892] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 02/21/2018] [Indexed: 11/26/2022] Open
Abstract
Most weakly electric fish navigate and communicate by sensing electric signals generated by their muscle-derived electric organs. Adults of one lineage (Apteronotidae), which discharge their electric organs in excess of 1 kHz, instead have an electric organ derived from the axons of specialized spinal neurons (electromotorneurons [EMNs]). EMNs fire spontaneously and are the fastest-firing neurons known. This biophysically extreme phenotype depends upon a persistent sodium current, the molecular underpinnings of which remain unknown. We show that a skeletal muscle–specific sodium channel gene duplicated in this lineage and, within approximately 2 million years, began expressing in the spinal cord, a novel site of expression for this isoform. Concurrently, amino acid replacements that cause a persistent sodium current accumulated in the regions of the channel underlying inactivation. Therefore, a novel adaptation allowing extreme neuronal firing arose from the duplication, change in expression, and rapid sequence evolution of a muscle-expressing sodium channel gene. The electrical properties of excitable cells, such as those in muscle and nervous tissue, were enabled in large part by the evolution of voltage-gated ion channel genes. The regulated conduction of ions through these channels results in the propagation of electrical signals, facilitating communication between cells. Here, we investigated how voltage-gated sodium (Nav) channels contributed to the evolution of a novel electric organ system in the Apteronotids—a lineage of weakly electric fish. This organ is developmentally derived from motor neurons and used for communication between individual fish, as well as for probing their nocturnal environment. We used transcriptomic data to show that the gene encoding a broadly conserved muscle-specific sodium channel was duplicated in an ancestral fish. One duplicated gene copy subsequently gained expression in the spinal cord, where the electric organ is located. Through evolutionary analysis and biophysical experiments, we demonstrate that sequence changes in this new sodium channel transformed its function to cause novel electrical properties that can facilitate spontaneous high-frequency action potentials. This study shows that duplicate genes can gain highly novel expression patterns and quickly adapt to contribute to the phenotypic evolution of novel organ systems.
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Affiliation(s)
- Ammon Thompson
- Department of Integrative Biology, The University of Texas, Austin, Texas, United States of America
- Department of Neuroscience, The University of Texas, Austin, Texas, United States of America
- * E-mail:
| | - Daniel T. Infield
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa, United States of America
| | - Adam R. Smith
- Department of Biology and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, Indiana, United States of America
| | - G. Troy Smith
- Department of Biology and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, Indiana, United States of America
| | - Christopher A. Ahern
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa, United States of America
| | - Harold H. Zakon
- Department of Integrative Biology, The University of Texas, Austin, Texas, United States of America
- Department of Neuroscience, The University of Texas, Austin, Texas, United States of America
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Moriyama Y, Koshiba-Takeuchi K. Significance of whole-genome duplications on the emergence of evolutionary novelties. Brief Funct Genomics 2018; 17:329-338. [DOI: 10.1093/bfgp/ely007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yuuta Moriyama
- Institute of Science and Technology Austria (IST), Klosterneuburg, Austria
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39
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Gallant JR, Losilla M, Tomlinson C, Warren WC. The Genome and Adult Somatic Transcriptome of the Mormyrid Electric Fish Paramormyrops kingsleyae. Genome Biol Evol 2017; 9:3525-3530. [PMID: 29240929 PMCID: PMC5751062 DOI: 10.1093/gbe/evx265] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/11/2017] [Indexed: 12/23/2022] Open
Abstract
Several studies have begun to elucidate the genetic and developmental processes underlying major vertebrate traits. Few of these traits have evolved repeatedly in vertebrates, preventing the analysis of molecular mechanisms underlying these traits comparatively. Electric organs have evolved multiple times among vertebrates, presenting a unique opportunity to understand the degree of constraint and repeatability of the evolutionary processes underlying novel vertebrate traits. As there is now a completed genome sequence representing South American electric eels, we were motivated to obtain genomic sequence from a linage that independently evolved electric organs to facilitate future comparative analyses of the evolution and development of electric organs. We report here the sequencing and de novo assembly of the genome of the mormyrid Paramormyrops kingsleyae using short-read sequencing. In addition, we have completed a somatic transcriptome from 11 tissues to construct a gene expression atlas of predicted genes from this assembly, enabling us to identify candidate housekeeping genes as well as genes differentially expressed in the major somatic tissues of the mormyrid electric fish. We anticipate that this resource will greatly facilitate comparative studies on the evolution and development of electric organs and electroreceptors.
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Affiliation(s)
- Jason R Gallant
- Department of Integrative Biology, Michigan State University
| | | | - Chad Tomlinson
- McDonnell Genome Institute, Washington University, St Louis
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40
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Tasdighian S, Van Bel M, Li Z, Van de Peer Y, Carretero-Paulet L, Maere S. Reciprocally Retained Genes in the Angiosperm Lineage Show the Hallmarks of Dosage Balance Sensitivity. THE PLANT CELL 2017; 29:2766-2785. [PMID: 29061868 PMCID: PMC5728127 DOI: 10.1105/tpc.17.00313] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 10/10/2017] [Accepted: 10/23/2017] [Indexed: 05/20/2023]
Abstract
In several organisms, particular functional categories of genes, such as regulatory and complex-forming genes, are preferentially retained after whole-genome multiplications but rarely duplicate through small-scale duplication, a pattern referred to as reciprocal retention. This peculiar duplication behavior is hypothesized to stem from constraints on the dosage balance between the genes concerned and their interaction context. However, the evidence for a relationship between reciprocal retention and dosage balance sensitivity remains fragmentary. Here, we identified which gene families are most strongly reciprocally retained in the angiosperm lineage and studied their functional and evolutionary characteristics. Reciprocally retained gene families exhibit stronger sequence divergence constraints and lower rates of functional and expression divergence than other gene families, suggesting that dosage balance sensitivity is a general characteristic of reciprocally retained genes. Gene families functioning in regulatory and signaling processes are much more strongly represented at the top of the reciprocal retention ranking than those functioning in multiprotein complexes, suggesting that regulatory imbalances may lead to stronger fitness effects than classical stoichiometric protein complex imbalances. Finally, reciprocally retained duplicates are often subject to dosage balance constraints for prolonged evolutionary times, which may have repercussions for the ease with which genome multiplications can engender evolutionary innovation.
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Affiliation(s)
- Setareh Tasdighian
- Ghent University, Department of Plant Biotechnology and Bioinformatics, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
- Bioinformatics Institute Ghent, Ghent University, B-9052 Ghent, Belgium
| | - Michiel Van Bel
- Ghent University, Department of Plant Biotechnology and Bioinformatics, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
- Bioinformatics Institute Ghent, Ghent University, B-9052 Ghent, Belgium
| | - Zhen Li
- Ghent University, Department of Plant Biotechnology and Bioinformatics, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
- Bioinformatics Institute Ghent, Ghent University, B-9052 Ghent, Belgium
| | - Yves Van de Peer
- Ghent University, Department of Plant Biotechnology and Bioinformatics, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
- Bioinformatics Institute Ghent, Ghent University, B-9052 Ghent, Belgium
- Genomics Research Institute, University of Pretoria, Pretoria 0028, South Africa
| | - Lorenzo Carretero-Paulet
- Ghent University, Department of Plant Biotechnology and Bioinformatics, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
- Bioinformatics Institute Ghent, Ghent University, B-9052 Ghent, Belgium
| | - Steven Maere
- Ghent University, Department of Plant Biotechnology and Bioinformatics, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
- Bioinformatics Institute Ghent, Ghent University, B-9052 Ghent, Belgium
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41
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Zakon HH, Li W, Pillai NE, Tohari S, Shingate P, Ren J, Venkatesh B. Voltage-gated sodium channel gene repertoire of lampreys: gene duplications, tissue-specific expression and discovery of a long-lost gene. Proc Biol Sci 2017; 284:20170824. [PMID: 28931746 PMCID: PMC5627192 DOI: 10.1098/rspb.2017.0824] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 08/17/2017] [Indexed: 12/14/2022] Open
Abstract
Studies of the voltage-gated sodium (Nav) channels of extant gnathostomes have made it possible to deduce that ancestral gnathostomes possessed four voltage-gated sodium channel genes derived from a single ancestral chordate gene following two rounds of genome duplication early in vertebrates. We investigated the Nav gene family in two species of lampreys (the Japanese lamprey Lethenteron japonicum and sea lamprey Petromyzon marinus) (jawless vertebrates-agnatha) and compared them with those of basal vertebrates to better understand the origin of Nav genes in vertebrates. We noted six Nav genes in both lamprey species, but orthology with gnathostome (jawed vertebrate) channels was inconclusive. Surprisingly, the Nav2 gene, ubiquitously found in invertebrates and believed to have been lost in vertebrates, is present in lampreys, elephant shark (Callorhinchus milii) and coelacanth (Latimeria chalumnae). Despite repeated duplication of the Nav1 family in vertebrates, Nav2 is only in single copy in those vertebrates in which it is retained, and was independently lost in ray-finned fishes and tetrapods. Of the other five Nav channel genes, most were expressed in brain, one in brain and heart, and one exclusively in skeletal muscle. Invertebrates do not express Nav channel genes in muscle. Thus, early in the vertebrate lineage Nav channels began to diversify and different genes began to express in heart and muscle.
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Affiliation(s)
- Harold H Zakon
- Department of Neuroscience, The University of Texas, Austin, TX 78712, USA
- Department of Integrative Biology, The University of Texas, Austin, TX 78712, USA
| | - Weiming Li
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA
| | - Nisha E Pillai
- Comparative and Medical Genomics Lab, Institute of Molecular and Cell Biology, A*STAR, Biopolis, 138673, Singapore
| | - Sumanty Tohari
- Comparative and Medical Genomics Lab, Institute of Molecular and Cell Biology, A*STAR, Biopolis, 138673, Singapore
| | - Prashant Shingate
- Comparative and Medical Genomics Lab, Institute of Molecular and Cell Biology, A*STAR, Biopolis, 138673, Singapore
| | - Jianfeng Ren
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai 201306, People's Republic of China
| | - Byrappa Venkatesh
- Comparative and Medical Genomics Lab, Institute of Molecular and Cell Biology, A*STAR, Biopolis, 138673, Singapore
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, 119228, Singapore
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Ackerly KL, Chapman LJ, Krahe R. Hypoxia acclimation increases novelty response strength during fast-starts in the African mormyrid, Marcusenius victoriae. Comp Biochem Physiol A Mol Integr Physiol 2017; 213:36-45. [PMID: 28844972 DOI: 10.1016/j.cbpa.2017.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 08/16/2017] [Accepted: 08/20/2017] [Indexed: 10/19/2022]
Abstract
Many fishes perform quick and sudden swimming maneuvers known as fast-starts to escape when threatened. In pulse-type weakly electric fishes these responses are accompanied by transient increases in the rate of electric signal production known as novelty responses. While novelty responses may increase an individual's information about their surroundings, they are aerobically powered and may come at a high energetic cost when compared to fast-starts, which rely primarily on anaerobic muscle. The juxtaposition between two key aspects of fast-starts in these fishes - the aerobic novelty response and the anaerobic swimming performance - makes them an interesting model for studying effects of hypoxia on escape performance and sensory information acquisition. We acclimated the hypoxia-tolerant African mormyrid Marcusenius victoriae to either high or low dissolved oxygen (DO) levels for 8weeks, after which fast-starts and novelty responses were quantified under both high (normoxic) and low-DO (hypoxic) test conditions. Hypoxia-acclimated fish exhibited higher maximum curvature than normoxia-acclimated fish. Displacement of normoxia-acclimated fish was not reduced under acute hypoxic test conditions. Novelty responses were given upon each startle, whether or not the fish performed a fast-start; however, novelty responses associated with fast-starts were significantly stronger than those without, suggesting a functional link between fast-start initiation and the motor control of the novelty response. Overall, hypoxia-acclimated individuals produced significantly stronger novelty responses during fast-starts. We suggest that increased novelty response strength in hypoxia-acclimated fish corresponds to an increased rate of sensory sampling, which may compensate for potential negative effects of hypoxia on higher-level processing.
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Affiliation(s)
- Kerri L Ackerly
- Department of Biology, McGill University, Montreal H3A 1B1, Quebec, Canada.
| | - Lauren J Chapman
- Department of Biology, McGill University, Montreal H3A 1B1, Quebec, Canada
| | - Rüdiger Krahe
- Department of Biology, McGill University, Montreal H3A 1B1, Quebec, Canada
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Turetzek N, Khadjeh S, Schomburg C, Prpic NM. Rapid diversification of homothorax expression patterns after gene duplication in spiders. BMC Evol Biol 2017; 17:168. [PMID: 28709396 PMCID: PMC5513375 DOI: 10.1186/s12862-017-1013-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/04/2017] [Indexed: 01/09/2023] Open
Abstract
Background Gene duplications provide genetic material for the evolution of new morphological and physiological features. One copy can preserve the original gene functions while the second copy may evolve new functions (neofunctionalisation). Gene duplications may thus provide new genes involved in evolutionary novelties. Results We have studied the duplicated homeobox gene homothorax (hth) in the spider species Parasteatoda tepidariorum and Pholcus phalangioides and have compared these data with previously published data from additional spider species. We show that the expression pattern of hth1 is highly conserved among spiders, consistent with the notion that this gene copy preserves the original hth functions. By contrast, hth2 has a markedly different expression profile especially in the prosomal appendages. The pattern in the pedipalps and legs consists of several segmental rings, suggesting a possible role of hth2 in limb joint development. Intriguingly, however, the hth2 pattern is much less conserved between the species than hth1 and shows a species specific pattern in each species investigated so far. Conclusions We hypothesise that the hth2 gene has gained a new patterning function after gene duplication, but has then undergone a second phase of diversification of its new role in the spider clade. The evolution of hth2 may thus provide an interesting example for a duplicated gene that has not only contributed to genetic diversity through neofunctionalisation, but beyond that has been able to escape evolutionary conservation after neofunctionalisation thus forming the basis for further genetic diversification. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-1013-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Natascha Turetzek
- Abteilung für Entwicklungsbiologie, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Georg-August-Universität, Göttingen, Germany.,Göttingen Center for Molecular Biosciences (GZMB), Ernst-Caspari-Haus, Göttingen, Germany.,Current address: Georg-August-Universität Göttingen, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Abteilung Zelluläre Neurobiologie, 37077, Göttingen, Germany
| | - Sara Khadjeh
- Abteilung für Entwicklungsbiologie, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Georg-August-Universität, Göttingen, Germany.,Göttingen Center for Molecular Biosciences (GZMB), Ernst-Caspari-Haus, Göttingen, Germany.,Present address: Clinic for Cardiology and Pneumology, University Medical Center Göttingen (UMG), Georg-August-University, Göttingen, Germany
| | - Christoph Schomburg
- Abteilung für Entwicklungsbiologie, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Georg-August-Universität, Göttingen, Germany.,Göttingen Center for Molecular Biosciences (GZMB), Ernst-Caspari-Haus, Göttingen, Germany
| | - Nikola-Michael Prpic
- Abteilung für Entwicklungsbiologie, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Georg-August-Universität, Göttingen, Germany. .,Göttingen Center for Molecular Biosciences (GZMB), Ernst-Caspari-Haus, Göttingen, Germany.
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Traeger LL, Sabat G, Barrett-Wilt GA, Wells GB, Sussman MR. A tail of two voltages: Proteomic comparison of the three electric organs of the electric eel. SCIENCE ADVANCES 2017; 3:e1700523. [PMID: 28695212 PMCID: PMC5498108 DOI: 10.1126/sciadv.1700523] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/19/2017] [Indexed: 05/22/2023]
Abstract
The electric eel (Electrophorus electricus) is unusual among electric fishes because it has three pairs of electric organs that serve multiple biological functions: For navigation and communication, it emits continuous pulses of weak electric discharge (<1 V), but for predation and defense, it intermittently emits lethal strong electric discharges (10 to 600 V). We hypothesized that these two electrogenic outputs have different energetic demands reflected by differences in their proteome and phosphoproteome. We report the use of isotope-assisted quantitative mass spectrometry to test this hypothesis. We observed novel phosphorylation sites in sodium transporters and identified a potassium channel with unique differences in protein concentration among the electric organs. In addition, we found transcription factors and protein kinases that show differential abundance in the strong versus weak electric organs. Our findings support the hypothesis that proteomic differences among electric organs underlie differences in energetic needs, reflecting a trade-off between generating weak voltages continuously and strong voltages intermittently.
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Affiliation(s)
- Lindsay L. Traeger
- Department of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
- Biotechnology Center, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Grzegorz Sabat
- Biotechnology Center, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Gregg B. Wells
- Department of Molecular and Cellular Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Michael R. Sussman
- Biotechnology Center, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Corresponding author.
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Rich M, Sullivan JP, Hopkins CD. Rediscovery and description of Paramormyrops sphekodes (Sauvage, 1879) and a new cryptic Paramormyrops (Mormyridae: Osteoglossiformes) from the Ogooué River of Gabon using morphometrics, DNA sequencing and electrophysiology. Zool J Linn Soc 2017. [DOI: 10.1093/zoolinnean/zlw004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Madeline Rich
- College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
- Cornell University Museum of Vertebrates, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA
| | - John P. Sullivan
- Cornell University Museum of Vertebrates, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA
| | - Carl D. Hopkins
- Cornell University Museum of Vertebrates, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA
- Department of Neurobiology and Behavior, 265 Seeley G. Mudd Hall, Cornell University, Ithaca, NY 14853-2702, USA
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Nagel R, Kirschbaum F, Tiedemann R. Electric organ discharge diversification in mormyrid weakly electric fish is associated with differential expression of voltage-gated ion channel genes. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:183-195. [DOI: 10.1007/s00359-017-1151-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 01/23/2017] [Accepted: 01/25/2017] [Indexed: 11/30/2022]
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Ching B, Woo JM, Hiong KC, Boo MV, Wong WP, Chew SF, Ip YK. Voltage-Gated Na+ Channel Isoforms and Their mRNA Expression Levels and Protein Abundance in Three Electric Organs and the Skeletal Muscle of the Electric Eel Electrophorus electricus. PLoS One 2016; 11:e0167589. [PMID: 27907137 PMCID: PMC5132174 DOI: 10.1371/journal.pone.0167589] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/16/2016] [Indexed: 11/18/2022] Open
Abstract
This study aimed to obtain the coding cDNA sequences of voltage-gated Na+ channel (scn) α-subunit (scna) and β-subunit (scnb) isoforms from, and to quantify their transcript levels in, the main electric organ (EO), Hunter's EO, Sach's EO and the skeletal muscle (SM) of the electric eel, Electrophorus electricus, which can generate both high and low voltage electric organ discharges (EODs). The full coding sequences of two scna (scn4aa and scn4ab) and three scnb (scn1b, scn2b and scn4b) were identified for the first time (except scn4aa) in E. electricus. In adult fish, the scn4aa transcript level was the highest in the main EO and the lowest in the Sach's EO, indicating that it might play an important role in generating high voltage EODs. For scn4ab/Scn4ab, the transcript and protein levels were unexpectedly high in the EOs, with expression levels in the main EO and the Hunter's EO comparable to those of scn4aa. As the key domains affecting the properties of the channel were mostly conserved between Scn4aa and Scn4ab, Scn4ab might play a role in electrogenesis. Concerning scnb, the transcript level of scn4b was much higher than those of scn1b and scn2b in the EOs and the SM. While the transcript level of scn4b was the highest in the main EO, protein abundance of Scn4b was the highest in the SM. Taken together, it is unlikely that Scna could function independently to generate EODs in the EOs as previously suggested. It is probable that different combinations of Scn4aa/Scn4ab and various Scnb isoforms in the three EOs account for the differences in EODs produced in E. electricus. In general, the transcript levels of various scn isoforms in the EOs and the SM were much higher in adult than in juvenile, and the three EOs of the juvenile fish could be functionally indistinct.
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Affiliation(s)
- Biyun Ching
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Republic of Singapore
| | - Jia M. Woo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Republic of Singapore
| | - Kum C. Hiong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Republic of Singapore
| | - Mel V. Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Republic of Singapore
| | - Wai P. Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Republic of Singapore
| | - Shit F. Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Republic of Singapore
| | - Yuen K. Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Republic of Singapore
- The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Republic of Singapore
- * E-mail:
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Pitchers WR, Constantinou SJ, Losilla M, Gallant JR. Electric fish genomics: Progress, prospects, and new tools for neuroethology. ACTA ACUST UNITED AC 2016; 110:259-272. [PMID: 27769923 DOI: 10.1016/j.jphysparis.2016.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/06/2016] [Accepted: 10/16/2016] [Indexed: 01/01/2023]
Abstract
Electric fish have served as a model system in biology since the 18th century, providing deep insight into the nature of bioelectrogenesis, the molecular structure of the synapse, and brain circuitry underlying complex behavior. Neuroethologists have collected extensive phenotypic data that span biological levels of analysis from molecules to ecosystems. This phenotypic data, together with genomic resources obtained over the past decades, have motivated new and exciting hypotheses that position the weakly electric fish model to address fundamental 21st century biological questions. This review article considers the molecular data collected for weakly electric fish over the past three decades, and the insights that data of this nature has motivated. For readers relatively new to molecular genetics techniques, we also provide a table of terminology aimed at clarifying the numerous acronyms and techniques that accompany this field. Next, we pose a research agenda for expanding genomic resources for electric fish research over the next 10years. We conclude by considering some of the exciting research prospects for neuroethology that electric fish genomics may offer over the coming decades, if the electric fish community is successful in these endeavors.
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Affiliation(s)
- William R Pitchers
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA.
| | - Savvas J Constantinou
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA
| | - Mauricio Losilla
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA
| | - Jason R Gallant
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA.
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Phylogenetic Systematics, Biogeography, and Ecology of the Electric Fish Genus Brachyhypopomus (Ostariophysi: Gymnotiformes). PLoS One 2016; 11:e0161680. [PMID: 27736882 PMCID: PMC5063478 DOI: 10.1371/journal.pone.0161680] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 08/10/2016] [Indexed: 11/23/2022] Open
Abstract
A species-level phylogenetic reconstruction of the Neotropical bluntnose knifefish genus Brachyhypopomus (Gymnotiformes, Hypopomidae) is presented, based on 60 morphological characters, approximately 1100 base pairs of the mitochondrial cytb gene, and approximately 1000 base pairs of the nuclear rag2 gene. The phylogeny includes 28 species of Brachyhypopomus and nine outgroup species from nine other gymnotiform genera, including seven in the superfamily Rhamphichthyoidea (Hypopomidae and Rhamphichthyidae). Parsimony and Bayesian total evidence phylogenetic analyses confirm the monophyly of the genus, and identify nine robust species groups. Homoplastic osteological characters associated with diminutive body size and occurrence in small stream habitats, including loss of squamation and simplifications of the skeleton, appear to mislead a phylogenetic analysis based on morphological characters alone–resulting in the incorrect placing of Microsternarchus + Racenisia in a position deeply nested within Brachyhypopomus. Consideration of geographical distribution in light of the total evidence phylogeny indicates an origin for Brachyhypopomus in Greater Amazonia (the superbasin comprising the Amazon, Orinoco and major Guiana drainages), with subsequent dispersal and vicariance in peripheral basins, including the La Plata, the São Francisco, and trans-Andean basins of northwest South America and Central America. The ancestral habitat of Brachyhypopomus likely resembled the normoxic, low-conductivity terra firme stream system occupied by many extant species, and the genus has subsequently occupied a wide range of terra firme and floodplain habitats including low- and high-conductivity systems, and normoxic and hypoxic systems. Adaptations for impedance matching to high conductivity, and/or for air breathing in hypoxic systems have attended these habitat transitions. Several species of Brachyhypopomus are eurytopic with respect to habitat occupancy and these generally exhibit wider geographical ranges than stenotopic species.
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Evidence for Non-neutral Evolution in a Sodium Channel Gene in African Weakly Electric Fish (Campylomormyrus, Mormyridae). J Mol Evol 2016; 83:61-77. [PMID: 27481396 DOI: 10.1007/s00239-016-9754-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 07/23/2016] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channels, Nav1, play a crucial role in the generation and propagation of action potentials and substantially contribute to the shape of their rising phase. The electric organ discharge (EOD) of African weakly electric fish (Mormyroidea) is the sum of action potentials fired from all electrocytes of the electric organ at the same time and hence voltage-gated sodium channels are one factor-together with the electrocyte's morphology and innervation pattern-that determines the properties of these EODs. Due to the fish-specific genome duplication, teleost fish possess eight copies of sodium channel genes (SCN), which encode for Nav1 channels. In mormyroids, SCN4aa is solely expressed in the electrocytes of the adult electric organ. In this study, we compared entire SCN4aa sequences of six species of the genus Campylomormyrus and identified nonsynonymous substitutions among them. SCN4aa in Campylomormyrus exhibits a much higher evolutionary rate compared to its paralog SCN4ab, whose expression is not restricted to the electric organ. We also found evidence for strong positive selection on the SCN4aa gene within Mormyridae and along the lineage ancestral to the Mormyridae. We have identified sites at which all nonelectric teleosts are monomorphic in their amino acid, but mormyrids have different amino acids. Our findings confirm the crucial role of SCN4aa in EOD evolution among mormyrid weakly electric fish. The inferred positive selection within Mormyridae makes this gene a prime candidate for further investigation of the divergent evolution of pulse-type EODs among closely related species.
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