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Sachkova MY. Evolutionary origin of the nervous system from Ctenophora prospective. Evol Dev 2024:e12472. [PMID: 38390763 DOI: 10.1111/ede.12472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 02/09/2024] [Accepted: 02/10/2024] [Indexed: 02/24/2024]
Abstract
Nervous system is one of the key adaptations underlying the evolutionary success of the majority of animal groups. Ctenophores (or comb jellies) are gelatinous marine invertebrates that were probably the first lineage to diverge from the rest of animals. Due to the key phylogenetic position and multiple unique adaptations, the noncentralized nervous system of comb jellies has been in the center of the debate around the origin of the nervous system in the animal kingdom and whether it happened only once or twice. Here, we discuss the latest findings in ctenophore neuroscience and multiple challenges on the way to build a clear evolutionary picture of the origin of the nervous system.
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Affiliation(s)
- Maria Y Sachkova
- School of Biological Sciences, University of Bristol, Bristol, UK
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2
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Mitchell DG, Edgar A, Mateu JR, Ryan JF, Martindale MQ. The ctenophore Mnemiopsis leidyi deploys a rapid injury response dating back to the last common animal ancestor. Commun Biol 2024; 7:203. [PMID: 38374160 PMCID: PMC10876535 DOI: 10.1038/s42003-024-05901-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 02/08/2024] [Indexed: 02/21/2024] Open
Abstract
Regenerative potential is widespread but unevenly distributed across animals. However, our understanding of the molecular mechanisms underlying regenerative processes is limited to a handful of model organisms, restricting robust comparative analyses. Here, we conduct a time course of RNA-seq during whole body regeneration in Mnemiopsis leidyi (Ctenophora) to uncover gene expression changes that correspond with key events during the regenerative timeline of this species. We identified several genes highly enriched in this dataset beginning as early as 10 minutes after surgical bisection including transcription factors in the early timepoints, peptidases in the middle timepoints, and cytoskeletal genes in the later timepoints. We validated the expression of early response transcription factors by whole mount in situ hybridization, showing that these genes exhibited high expression in tissues surrounding the wound site. These genes exhibit a pattern of transient upregulation as seen in a variety of other organisms, suggesting that they may be initiators of an ancient gene regulatory network linking wound healing to the initiation of a regenerative response.
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Affiliation(s)
- Dorothy G Mitchell
- Whitney Laboratory for Marine Bioscience, University of Florida, Saint Augustine, FL, USA
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Allison Edgar
- Whitney Laboratory for Marine Bioscience, University of Florida, Saint Augustine, FL, USA
| | - Júlia Ramon Mateu
- Whitney Laboratory for Marine Bioscience, University of Florida, Saint Augustine, FL, USA
| | - Joseph F Ryan
- Whitney Laboratory for Marine Bioscience, University of Florida, Saint Augustine, FL, USA
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, Saint Augustine, FL, USA.
- Department of Biology, University of Florida, Gainesville, FL, USA.
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3
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Moroz LL. Brief History of Ctenophora. Methods Mol Biol 2024; 2757:1-26. [PMID: 38668961 DOI: 10.1007/978-1-0716-3642-8_1] [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] [Indexed: 05/04/2024]
Abstract
Ctenophores are the descendants of the earliest surviving lineage of ancestral metazoans, predating the branch leading to sponges (Ctenophore-first phylogeny). Emerging genomic, ultrastructural, cellular, and systemic data indicate that virtually every aspect of ctenophore biology as well as ctenophore development are remarkably different from what is described in representatives of other 32 animal phyla. The outcome of this reconstruction is that most system-level components associated with the ctenophore organization result from convergent evolution. In other words, the ctenophore lineage independently evolved as high animal complexities with the astonishing diversity of cell types and structures as bilaterians and cnidarians. Specifically, neurons, synapses, muscles, mesoderm, through gut, sensory, and integrative systems evolved independently in Ctenophora. Rapid parallel evolution of complex traits is associated with a broad spectrum of unique ctenophore-specific molecular innovations, including alternative toolkits for making an animal. However, the systematic studies of ctenophores are in their infancy, and deciphering their remarkable morphological and functional diversity is one of the hot topics in biological research, with many anticipated surprises.
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Affiliation(s)
- Leonid L Moroz
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, USA.
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4
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Formery L, Lowe CJ. Integrating Complex Life Cycles in Comparative Developmental Biology. Annu Rev Genet 2023; 57:321-339. [PMID: 37585618 DOI: 10.1146/annurev-genet-071719-020641] [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] [Indexed: 08/18/2023]
Abstract
The goal of comparative developmental biology is identifying mechanistic differences in embryonic development between different taxa and how these evolutionary changes have led to morphological and organizational differences in adult body plans. Much of this work has focused on direct-developing species in which the adult forms straight from the embryo and embryonic modifications have direct effects on the adult. However, most animal lineages are defined by indirect development, in which the embryo gives rise to a larval body plan and the adult forms by transformation of the larva. Historically, much of our understanding of complex life cycles is viewed through the lenses of ecology and zoology. In this review, we discuss the importance of establishing developmental rather than morphological or ecological criteria for defining developmental mode and explicitly considering the evolutionary implications of incorporating complex life cycles into broad developmental comparisons of embryos across metazoans.
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Affiliation(s)
- Laurent Formery
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, USA;
- Department of Cell and Molecular Biology, University of California, Berkeley, California, USA
| | - Christopher J Lowe
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, USA;
- Chan Zuckerberg BioHub, San Francisco, California, USA
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Burkhardt P, Colgren J, Medhus A, Digel L, Naumann B, Soto-Angel JJ, Nordmann EL, Sachkova MY, Kittelmann M. Syncytial nerve net in a ctenophore adds insights on the evolution of nervous systems. Science 2023; 380:293-297. [PMID: 37079688 DOI: 10.1126/science.ade5645] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
A fundamental breakthrough in neurobiology has been the formulation of the neuron doctrine by Santiago Ramón y Cajal, which stated that the nervous system is composed of discrete cells. Electron microscopy later confirmed the doctrine and allowed the identification of synaptic connections. In this work, we used volume electron microscopy and three-dimensional reconstructions to characterize the nerve net of a ctenophore, a marine invertebrate that belongs to one of the earliest-branching animal lineages. We found that neurons in the subepithelial nerve net have a continuous plasma membrane that forms a syncytium. Our findings suggest fundamental differences of nerve net architectures between ctenophores and cnidarians or bilaterians and offer an alternative perspective on neural network organization and neurotransmission.
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Affiliation(s)
- Pawel Burkhardt
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Jeffrey Colgren
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Astrid Medhus
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Leonid Digel
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Benjamin Naumann
- Institut für Biowissenschaften, Allgemeine und Spezielle Zoologie, Universität Rostock, 18055 Rostock, Germany
| | | | | | | | - Maike Kittelmann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
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Are we there yet to eliminate the terms larva, metamorphosis, and dissogeny from the ctenophore literature? Proc Natl Acad Sci U S A 2023; 120:e2218317120. [PMID: 36649425 PMCID: PMC9942804 DOI: 10.1073/pnas.2218317120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Reply to Soto-Angel et al.: Is "larva" a natural kind? Phylogenetic thinking provides clarity. Proc Natl Acad Sci U S A 2023; 120:e2219704120. [PMID: 36649416 PMCID: PMC9942860 DOI: 10.1073/pnas.2219704120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Johnson SB, Winnikoff JR, Schultz DT, Christianson LM, Patry WL, Mills CE, Haddock SHD. Speciation of pelagic zooplankton: Invisible boundaries can drive isolation of oceanic ctenophores. Front Genet 2022; 13:970314. [PMID: 36276958 PMCID: PMC9585324 DOI: 10.3389/fgene.2022.970314] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
The study of evolution and speciation in non-model systems provides us with an opportunity to expand our understanding of biodiversity in nature. Connectivity studies generally focus on species with obvious boundaries to gene flow, but in open-ocean environments, such boundaries are difficult to identify. Due to the lack of obvious boundaries, speciation and population subdivision in the pelagic environment remain largely unexplained. Comb jellies (Phylum Ctenophora) are mostly planktonic gelatinous invertebrates, many of which are considered to have freely interbreeding distributions worldwide. It is thought that the lobate ctenophore Bolinopsis infundibulum is distributed throughout cooler northern latitudes and B. vitrea warmer. Here, we examined the global population structure for species of Bolinopsis with genetic and morphological data. We found distinct evolutionary patterns within the genus, where B. infundibulum had a broad distribution from northern Pacific to Atlantic waters despite many physical barriers, while other species were geographically segregated despite few barriers. Divergent patterns of speciation within the genus suggest that oceanic currents, sea-level, and geological changes over time can act as either barriers or aids to dispersal in the pelagic environment. Further, we used population genomic data to examine evolution in the open ocean of a distinct lineage of Bolinopsis ctenophores from the North Eastern Pacific. Genetic information and morphological observations validated this as a separate species, Bolinopsis microptera, which was previously described but has recently been called B. infundibulum. We found that populations of B. microptera from California were in cytonuclear discordance, which indicates a secondary contact zone for previously isolated populations. Discordance at this scale is rare, especially in a continuous setting.
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Affiliation(s)
- Shannon B. Johnson
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, United States
- *Correspondence: Shannon B. Johnson, ; Steven H. D. Haddock,
| | - Jacob R. Winnikoff
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, United States
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Darrin T. Schultz
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, United States
- Department of Neurosciences and Developmental Biology, University of Vienna, Vienna, Austria
- Department of Biomolecular Engineering and Bioinformatics, University of California, Santa Cruz, Santa Cruz, CA, United States
| | | | - Wyatt L. Patry
- Animal Care Division, Monterey Bay Aquarium, Monterey, CA, United States
| | - Claudia E. Mills
- Friday Harbor Laboratories and the Department of Biology, University of Washington, Friday Harbor, WA, United States
| | - Steven H. D. Haddock
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, United States
- *Correspondence: Shannon B. Johnson, ; Steven H. D. Haddock,
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Gilbert E, Teeling C, Lebedeva T, Pedersen S, Chrismas N, Genikhovich G, Modepalli V. Molecular and cellular architecture of the larval sensory organ in the cnidarian Nematostella vectensis. Development 2022; 149:276422. [PMID: 36000354 PMCID: PMC9481973 DOI: 10.1242/dev.200833] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 07/18/2022] [Indexed: 11/29/2022]
Abstract
Cnidarians are the only non-bilaterian group to evolve ciliated larvae with an apical sensory organ, which is possibly homologous to the apical organs of bilaterian primary larvae. Here, we generated transcriptomes of the apical tissue in the sea anemone Nematostella vectensis and showed that it has a unique neuronal signature. By integrating previously published larval single-cell data with our apical transcriptomes, we discovered that the apical domain comprises a minimum of six distinct cell types. We show that the apical organ is compartmentalised into apical tuft cells (spot) and larval-specific neurons (ring). Finally, we identify ISX-like (NVE14554), a PRD class homeobox gene specifically expressed in apical tuft cells, as an FGF signalling-dependent transcription factor responsible for the formation of the apical tuft domain via repression of the neural ring fate in apical cells. With this study, we contribute a comparison of the molecular anatomy of apical organs, which must be carried out across phyla to determine whether this crucial larval structure evolved once or multiple times. Summary:ISX-like homeobox gene is an FGF signalling-dependent transcription factor responsible for the formation of the apical tuft in the sea anemone Nematostella vectensis.
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Affiliation(s)
- Eleanor Gilbert
- Marine Biological Association of the UK, The Laboratory 1 , Citadel Hill, Plymouth PL1 2PB , United Kingdom
- School of Biological and Marine Sciences, University of Plymouth 2 , Plymouth, PL4 8AA , UK
| | - Callum Teeling
- Marine Biological Association of the UK, The Laboratory 1 , Citadel Hill, Plymouth PL1 2PB , United Kingdom
- School of Biological and Marine Sciences, University of Plymouth 2 , Plymouth, PL4 8AA , UK
| | - Tatiana Lebedeva
- University of Vienna 3 Department of Neurosciences and Developmental Biology, Faculty of Life Sciences , , Vienna, 1030 , Austria
- Doctoral School of Ecology and Evolution, University of Vienna 4 , Vienna, 1030 , Austria
| | - Siffreya Pedersen
- Marine Biological Association of the UK, The Laboratory 1 , Citadel Hill, Plymouth PL1 2PB , United Kingdom
| | - Nathan Chrismas
- Marine Biological Association of the UK, The Laboratory 1 , Citadel Hill, Plymouth PL1 2PB , United Kingdom
| | - Grigory Genikhovich
- University of Vienna 3 Department of Neurosciences and Developmental Biology, Faculty of Life Sciences , , Vienna, 1030 , Austria
| | - Vengamanaidu Modepalli
- Marine Biological Association of the UK, The Laboratory 1 , Citadel Hill, Plymouth PL1 2PB , United Kingdom
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Multigenerational laboratory culture of pelagic ctenophores and CRISPR-Cas9 genome editing in the lobate Mnemiopsis leidyi. Nat Protoc 2022; 17:1868-1900. [PMID: 35697825 DOI: 10.1038/s41596-022-00702-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 03/23/2022] [Indexed: 11/08/2022]
Abstract
Despite long-standing experimental interest in ctenophores due to their unique biology, ecological influence and evolutionary status, previous work has largely been constrained by the periodic seasonal availability of wild-caught animals and difficulty in reliably closing the life cycle. To address this problem, we have developed straightforward protocols that can be easily implemented to establish long-term multigenerational cultures for biological experimentation in the laboratory. In this protocol, we describe the continuous culture of the Atlantic lobate ctenophore Mnemiopsis leidyi. A rapid 3-week egg-to-egg generation time makes Mnemiopsis suitable for a wide range of experimental genetic, cellular, embryological, physiological, developmental, ecological and evolutionary studies. We provide recommendations for general husbandry to close the life cycle of Mnemiopsis in the laboratory, including feeding requirements, light-induced spawning, collection of embryos and rearing of juveniles to adults. These protocols have been successfully applied to maintain long-term multigenerational cultures of several species of pelagic ctenophores, and can be utilized by laboratories lacking easy access to the ocean. We also provide protocols for targeted genome editing via microinjection with CRISPR-Cas9 that can be completed within ~2 weeks, including single-guide RNA synthesis, early embryo microinjection, phenotype assessment and sequence validation of genome edits. These protocols provide a foundation for using Mnemiopsis as a model organism for functional genomic analyses in ctenophores.
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