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Vargas A, DeBiasse M, Dykes L, Edgar A, Hayes T, Groso D, Babonis L, Martindale M, Ryan J. Morphological and dietary changes encoded in the genome of Beroe ovata, a ctenophore-eating ctenophore. NAR Genom Bioinform 2024; 6:lqae072. [PMID: 38895105 PMCID: PMC11184263 DOI: 10.1093/nargab/lqae072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/03/2024] [Accepted: 05/30/2024] [Indexed: 06/21/2024] Open
Abstract
As the sister group to all other animals, ctenophores (comb jellies) are important for understanding the emergence and diversification of numerous animal traits. Efforts to explore the evolutionary processes that promoted diversification within Ctenophora are hindered by undersampling genomic diversity within this clade. To address this gap, we present the sequence, assembly and initial annotation of the genome of Beroe ovata. Beroe possess unique morphology, behavior, ecology and development. Unlike their generalist carnivorous kin, beroid ctenophores feed exclusively on other ctenophores. Accordingly, our analyses revealed a loss of chitinase, an enzyme critical for the digestion of most non-ctenophore prey, but superfluous for ctenophorivores. Broadly, our genomic analysis revealed that extensive gene loss and changes in gene regulation have shaped the unique biology of B. ovata. Despite the gene losses in B. ovata, our phylogenetic analyses on photosensitive opsins and several early developmental regulatory genes show that these genes are conserved in B. ovata. This additional sampling contributes to a more complete reconstruction of the ctenophore ancestor and points to the need for extensive comparisons within this ancient and diverse clade of animals. To promote further exploration of these data, we present BovaDB (http://ryanlab.whitney.ufl.edu/bovadb/), a portal for the B. ovata genome.
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Affiliation(s)
- Alexandra M Vargas
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Melissa B DeBiasse
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Department of Biology, Radford University, Radford, VA 24142, USA
| | - Lana L Dykes
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
| | - Allison Edgar
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Federated Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - T Danielle Hayes
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
| | - Daniel J Groso
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Leslie S Babonis
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Joseph F Ryan
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
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2
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Moroz LL. Syncytial nets vs. chemical signaling: emerging properties of alternative integrative systems. Front Cell Dev Biol 2023; 11:1320209. [PMID: 38125877 PMCID: PMC10730927 DOI: 10.3389/fcell.2023.1320209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023] Open
Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
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Moroz LL, Romanova DY. Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans). Front Cell Dev Biol 2022; 10:1071961. [PMID: 36619868 PMCID: PMC9816575 DOI: 10.3389/fcell.2022.1071961] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
How to make a neuron, a synapse, and a neural circuit? Is there only one 'design' for a neural architecture with a universally shared genomic blueprint across species? The brief answer is "No." Four early divergent lineages from the nerveless common ancestor of all animals independently evolved distinct neuroid-type integrative systems. One of these is a subset of neural nets in comb jellies with unique synapses; the second lineage is the well-known Cnidaria + Bilateria; the two others are non-synaptic neuroid systems in sponges and placozoans. By integrating scRNA-seq and microscopy data, we revise the definition of neurons as synaptically-coupled polarized and highly heterogenous secretory cells at the top of behavioral hierarchies with learning capabilities. This physiological (not phylogenetic) definition separates 'true' neurons from non-synaptically and gap junction-coupled integrative systems executing more stereotyped behaviors. Growing evidence supports the hypothesis of multiple origins of neurons and synapses. Thus, many non-bilaterian and bilaterian neuronal classes, circuits or systems are considered functional rather than genetic categories, composed of non-homologous cell types. In summary, little-explored examples of convergent neuronal evolution in representatives of early branching metazoans provide conceptually novel microanatomical and physiological architectures of behavioral controls in animals with prospects of neuro-engineering and synthetic biology.
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Affiliation(s)
- Leonid L. Moroz
- Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
| | - Daria Y. Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, 5A Butlerova, Moscow, Russia
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Mitchell DG, Edgar A, Martindale MQ. Improved histological fixation of gelatinous marine invertebrates. Front Zool 2021; 18:29. [PMID: 34118945 PMCID: PMC8196456 DOI: 10.1186/s12983-021-00414-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/17/2021] [Indexed: 11/10/2022] Open
Abstract
Background Gelatinous zooplankton can be difficult to preserve morphologically due to unique physical properties of their cellular and acellular components. The relatively large volume of mesoglea leads to distortion of the delicate morphology and poor sample integrity in specimens prepared with standard aldehyde or alcohol fixation techniques. Similar challenges have made it difficult to extend standard laboratory methods such as in situ hybridization to larger juvenile ctenophores, hampering studies of late development. Results We have found that a household water repellant glass treatment product commonly used in laboratories, Rain-X®, alone or in combination with standard aldehyde fixatives, greatly improves morphological preservation of such delicate samples. We present detailed methods for preservation of ctenophores of diverse sizes compatible with long-term storage or detection and localization of target molecules such as with immunohistochemistry and in situ hybridization and show that this fixation might be broadly useful for preservation of other delicate marine specimens. Conclusion This new method will enable superior preservation of morphology in gelatinous specimens for a variety of downstream goals. Extending this method may improve the morphological fidelity and durability of museum and laboratory specimens for other delicate sample types. Supplementary Information The online version contains supplementary material available at 10.1186/s12983-021-00414-z.
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Affiliation(s)
- Dorothy G Mitchell
- The Whitney Laboratory for Marine Bioscience, 9505 N, Ocean Shore Blvd, St. Augustine, FL, 32080-8610, USA
| | - Allison Edgar
- The Whitney Laboratory for Marine Bioscience, 9505 N, Ocean Shore Blvd, St. Augustine, FL, 32080-8610, USA
| | - Mark Q Martindale
- The Whitney Laboratory for Marine Bioscience, 9505 N, Ocean Shore Blvd, St. Augustine, FL, 32080-8610, USA.
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Jékely G, Godfrey-Smith P, Keijzer F. Reafference and the origin of the self in early nervous system evolution. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190764. [PMID: 33550954 PMCID: PMC7934971 DOI: 10.1098/rstb.2019.0764] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2020] [Indexed: 12/20/2022] Open
Abstract
Discussions of the function of early nervous systems usually focus on a causal flow from sensors to effectors, by which an animal coordinates its actions with exogenous changes in its environment. We propose, instead, that much early sensing was reafferent; it was responsive to the consequences of the animal's own actions. We distinguish two general categories of reafference-translocational and deformational-and use these to survey the distribution of several often-neglected forms of sensing, including gravity sensing, flow sensing and proprioception. We discuss sensing of these kinds in sponges, ctenophores, placozoans, cnidarians and bilaterians. Reafference is ubiquitous, as ongoing action, especially whole-body motility, will almost inevitably influence the senses. Corollary discharge-a pathway or circuit by which an animal tracks its own actions and their reafferent consequences-is not a necessary feature of reafferent sensing but a later-evolving mechanism. We also argue for the importance of reafferent sensing to the evolution of the body-self, a form of organization that enables an animal to sense and act as a single unit. This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.
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Affiliation(s)
- Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Peter Godfrey-Smith
- School of History and Philosophy of Science, University of Sydney, New South Wales 2006, Australia
| | - Fred Keijzer
- Department of Theoretical Philosophy, University of Groningen, Groningen, The Netherlands
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Jokura K, Inaba K. Structural diversity and distribution of cilia in the apical sense organ of the ctenophore Bolinopsis mikado. Cytoskeleton (Hoboken) 2020; 77:442-455. [PMID: 33103333 DOI: 10.1002/cm.21640] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 02/03/2023]
Abstract
The apical organ of ctenophores is the center of sensory information that controls locomotion. Previous studies have described several types of cilia in this organ. However, detailed ciliary structures, particularly axonemal structures, have not been extensively investigated. Here, we reported that the apical organ of the ctenophore Bolinopsis mikado contains six types of cilia with different axonemal structures. These include the typical "9 + 2" motile axonemes, with both outer and inner dynein arms, only the inner dynein arm, or no dynein arm; axonemes with electron-dense structures in the A-tubules; "9 + 0" axonemes lacking the central pair of microtubules; and axonemes with compartmenting lamellae. Considering that "9 + 2" axonemal structures with both dynein arms are thought to be ancestral forms of cilia, the apical organ of ctenophores would comprise an elaborate assembly of modified ciliary forms that sense and transmit extracellular stimuli and generate various fluid flows.
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Affiliation(s)
- Kei Jokura
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
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Kinetid in larval cells of Spongillida (Porifera: Demospongiae): tracing the ancestral traits. ORG DIVERS EVOL 2020. [DOI: 10.1007/s13127-020-00460-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Bezares-Calderón LA, Berger J, Jékely G. Diversity of cilia-based mechanosensory systems and their functions in marine animal behaviour. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190376. [PMID: 31884914 PMCID: PMC7017336 DOI: 10.1098/rstb.2019.0376] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2019] [Indexed: 12/12/2022] Open
Abstract
Sensory cells that detect mechanical forces usually have one or more specialized cilia. These mechanosensory cells underlie hearing, proprioception or gravity sensation. To date, it is unclear how cilia contribute to detecting mechanical forces and what is the relationship between mechanosensory ciliated cells in different animal groups and sensory systems. Here, we review examples of ciliated sensory cells with a focus on marine invertebrate animals. We discuss how various ciliated cells mediate mechanosensory responses during feeding, tactic responses or predator-prey interactions. We also highlight some of these systems as interesting and accessible models for future in-depth behavioural, functional and molecular studies. We envisage that embracing a broader diversity of organisms could lead to a more complete view of cilia-based mechanosensation. This article is part of the Theo Murphy meeting issue 'Unity and diversity of cilia in locomotion and transport'.
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Affiliation(s)
| | - Jürgen Berger
- Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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Norekian TP, Moroz LL. Neuromuscular organization of the Ctenophore
Pleurobrachia bachei. J Comp Neurol 2018; 527:406-436. [DOI: 10.1002/cne.24546] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 09/24/2018] [Accepted: 09/27/2018] [Indexed: 01/21/2023]
Affiliation(s)
- Tigran P. Norekian
- Whitney Laboratory for Marine Bioscience University of Florida St. Augustine Florida
- Friday Harbor Laboratories University of Washington Friday Harbor Washington
- Institute of Higher Nervous Activity and Neurophysiology Russian Academy of Sciences Moscow Russia
| | - Leonid L. Moroz
- Whitney Laboratory for Marine Bioscience University of Florida St. Augustine Florida
- Friday Harbor Laboratories University of Washington Friday Harbor Washington
- Departments of Neuroscience and McKnight Brain Institute University of Florida Gainesville Florida
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Tamm SL. Novel Structures Associated with Presumed Photoreceptors in the Aboral Sense Organ of Ctenophores. THE BIOLOGICAL BULLETIN 2016; 231:97-102. [PMID: 27820909 DOI: 10.1086/690089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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11
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Abstract
Genomic and transcriptomic analyses show that sponges possess a large repertoire of genes associated with neuronal processes in other animals, but what is the evidence these are used in a coordination or sensory context in sponges? The very different phylogenetic hypotheses under discussion today suggest very different scenarios for the evolution of tissues and coordination systems in early animals. The sponge genomic 'toolkit' either reflects a simple, pre-neural system used to protect the sponge filter or represents the remnants of a more complex signalling system and sponges have lost cell types, tissues and regionalization to suit their current suspension-feeding habit. Comparative transcriptome data can be informative but need to be assessed in the context of knowledge of sponge tissue structure and physiology. Here, I examine the elements of the sponge neural toolkit including sensory cells, conduction pathways, signalling molecules and the ionic basis of signalling. The elements described do not fit the scheme of a loss of sophistication, but seem rather to reflect an early specialization for suspension feeding, which fits with the presumed ecological framework in which the first animals evolved.
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Affiliation(s)
- Sally P Leys
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
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Tamm SL. Functional consequences of the asymmetric architecture of the ctenophore statocyst. THE BIOLOGICAL BULLETIN 2015; 229:173-184. [PMID: 26504158 DOI: 10.1086/bblv229n2p173] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ctenophores, or comb jellies, are geotactic with a statocyst that controls the activity of the eight ciliary comb rows. If a ctenophore is tilted or displaced from a position of vertical balance, it rights itself by asymmetric frequencies of beating on the uppermost and lowermost comb rows, turning to swim up or down depending on its mood. I recently discovered that the statocyst of ctenophores has an asymmetric architecture related to the sagittal and tentacular planes along the oral-aboral axis. The four groups of pacemaker balancer cilia are arranged in a rectangle along the tentacular plane, and support a superellipsoidal statolith elongated in the tentacular plane. By controlled tilting of immobilized ctenophores in either body plane with video recording of activated comb rows, I found that higher beat frequencies occurred in the sagittal than in the tentacular plane at orthogonal orientations. Similar tilting experiments on isolated statocyst slices showed that statolith displacement due to gravity and the resulting deflection of the mechanoresponsive balancers are greater in the sagittal plane. Finally, tilting experiments on a mechanical model gave results similar to those of real statocysts, indicating that the geometric asymmetries of statolith design are sufficient to account for my findings. The asymmetric architecture of the ctenophore statocyst thus has functional consequences, but a possible adaptive value is not known.
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Affiliation(s)
- Sidney L Tamm
- Bell Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543
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Abstract
Neurons are defined as polarized secretory cells specializing in directional propagation of electrical signals leading to the release of extracellular messengers - features that enable them to transmit information, primarily chemical in nature, beyond their immediate neighbors without affecting all intervening cells en route. Multiple origins of neurons and synapses from different classes of ancestral secretory cells might have occurred more than once during ~600 million years of animal evolution with independent events of nervous system centralization from a common bilaterian/cnidarian ancestor without the bona fide central nervous system. Ctenophores, or comb jellies, represent an example of extensive parallel evolution in neural systems. First, recent genome analyses place ctenophores as a sister group to other animals. Second, ctenophores have a smaller complement of pan-animal genes controlling canonical neurogenic, synaptic, muscle and immune systems, and developmental pathways than most other metazoans. However, comb jellies are carnivorous marine animals with a complex neuromuscular organization and sophisticated patterns of behavior. To sustain these functions, they have evolved a number of unique molecular innovations supporting the hypothesis of massive homoplasies in the organization of integrative and locomotory systems. Third, many bilaterian/cnidarian neuron-specific genes and 'classical' neurotransmitter pathways are either absent or, if present, not expressed in ctenophore neurons (e.g. the bilaterian/cnidarian neurotransmitter, γ-amino butyric acid or GABA, is localized in muscles and presumed bilaterian neuron-specific RNA-binding protein Elav is found in non-neuronal cells). Finally, metabolomic and pharmacological data failed to detect either the presence or any physiological action of serotonin, dopamine, noradrenaline, adrenaline, octopamine, acetylcholine or histamine - consistent with the hypothesis that ctenophore neural systems evolved independently from those in other animals. Glutamate and a diverse range of secretory peptides are first candidates for ctenophore neurotransmitters. Nevertheless, it is expected that other classes of signal and neurogenic molecules would be discovered in ctenophores as the next step to decipher one of the most distinct types of neural organization in the animal kingdom.
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Affiliation(s)
- Leonid L Moroz
- The Whitney Laboratory of Marine Biosciences and Department of Neuroscience and McKnight Brain Institute, University of Florida, FL 32080, USA. The Whitney Laboratory, University of Florida, 9505 Ocean Shore Boulevard, St. Augustine, FL 32080, USA
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Tamm SL. Formation of the statolith in the ctenophore Mnemiopsis leidyi. THE BIOLOGICAL BULLETIN 2014; 227:7-18. [PMID: 25216498 DOI: 10.1086/bblv227n1p7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The aboral sensory organ (apical organ) of ctenophores contains a statocyst with a single large statolith. The statolith comprises living cells (lithocytes), each containing a large membrane-bound concretion. The statolith is supported on the distal ends of four compound motile mechanoresponsive cilia (balancers) which control the beat frequencies of the eight locomotory comb rows, and thereby the orientation of animals to gravity. In Mnemiopsis leidyi and Pleurobrachia pileus, lithocytes arise in the thickened epithelial floor of the apical organ on opposite sides along the tentacular plane. Lithocytes progressively differentiate and migrate toward the apical surface where they bud off next to the bases of the balancers. New lithocytes are transported up the balancers by ciliary surface motility to form the statolith (Noda, 2013). The statolith has a superellipsoidal shape due to the rectangular arrangement of the four balancers and the addition of new lithocytes to its ends via the balancers. The size of the statolith increases with animal size, starting at the highest rate of growth in younger stages and gradually decreasing in larger animals. The total number of developing lithocytes in the epithelial floor increases rapidly in smaller animals and reaches a plateau range in larger animals. Lithocytes are therefore produced continually throughout life for enlargement of the statolith and possibly for turnover and replacement of existing lithocytes. The dome cilia enclosing the statocyst were observed to propagate slow, low-ampitude waves distally. The dome cilia may act as an undulating screen to prevent foreign objects in the seawater from being transported non-specifically up the balancers to make a defective statolith.
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Affiliation(s)
- Sidney L Tamm
- Bell Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543
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Simmons DK, Pang K, Martindale MQ. Lim homeobox genes in the Ctenophore Mnemiopsis leidyi: the evolution of neural cell type specification. EvoDevo 2012; 3:2. [PMID: 22239757 PMCID: PMC3283466 DOI: 10.1186/2041-9139-3-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 01/13/2012] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Nervous systems are thought to be important to the evolutionary success and diversification of metazoans, yet little is known about the origin of simple nervous systems at the base of the animal tree. Recent data suggest that ctenophores, a group of macroscopic pelagic marine invertebrates, are the most ancient group of animals that possess a definitive nervous system consisting of a distributed nerve net and an apical statocyst. This study reports on details of the evolution of the neural cell type specifying transcription factor family of LIM homeobox containing genes (Lhx), which have highly conserved functions in neural specification in bilaterian animals. RESULTS Using next generation sequencing, the first draft of the genome of the ctenophore Mnemiopsis leidyi has been generated. The Lhx genes in all animals are represented by seven subfamilies (Lhx1/5, Lhx3/4, Lmx, Islet, Lhx2/9, Lhx6/8, and LMO) of which four were found to be represented in the ctenophore lineage (Lhx1/5, Lhx3/4, Lmx, and Islet). Interestingly, the ctenophore Lhx gene complement is more similar to the sponge complement (sponges do not possess neurons) than to either the cnidarian-bilaterian or placozoan Lhx complements. Using whole mount in situ hybridization, the Lhx gene expression patterns were examined and found to be expressed around the blastopore and in cells that give rise to the apical organ and putative neural sensory cells. CONCLUSION This research gives us a first look at neural cell type specification in the ctenophore M. leidyi. Within M. leidyi, Lhx genes are expressed in overlapping domains within proposed neural cellular and sensory cell territories. These data suggest that Lhx genes likely played a conserved role in the patterning of sensory cells in the ancestor of sponges and ctenophores, and may provide a link to the expression of Lhx orthologs in sponge larval photoreceptive cells. Lhx genes were later co-opted into patterning more diversified complements of neural and non-neural cell types in later evolving animals.
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Affiliation(s)
- David K Simmons
- Kewalo Marine Laboratory, Department of Zoology, University of Hawaii at Manoa, Honolulu, HI, USA, 96813
| | - Kevin Pang
- Sars, International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
| | - Mark Q Martindale
- Kewalo Marine Laboratory, Department of Zoology, University of Hawaii at Manoa, Honolulu, HI, USA, 96813
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Jager M, Chiori R, Alié A, Dayraud C, Quéinnec E, Manuel M. New insights on ctenophore neural anatomy: Immunofluorescence study in Pleurobrachia pileus (Müller, 1776). JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2010; 316B:171-87. [DOI: 10.1002/jez.b.21386] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 09/27/2010] [Accepted: 10/12/2010] [Indexed: 01/14/2023]
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17
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Jager M, Quéinnec E, Chiori R, Le Guyader H, Manuel M. Insights into the early evolution ofSOXgenes from expression analyses in a ctenophore. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2008; 310:650-67. [DOI: 10.1002/jez.b.21244] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Pang K, Martindale MQ. Comb jellies (ctenophora): a model for Basal metazoan evolution and development. ACTA ACUST UNITED AC 2008; 2008:pdb.emo106. [PMID: 21356709 DOI: 10.1101/pdb.emo106] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
INTRODUCTIONCtenophores, or comb jellies, are a group of marine organisms whose unique biological features and phylogenetic placement make them a key taxon for understanding animal evolution. These gelatinous creatures are clearly distinct from cnidarian medusae (i.e., jellyfish). Key features present in the ctenophore body plan include biradial symmetry, an oral-aboral axis delimited by a mouth and an apical sensory organ, two tentacles, eight comb rows composed of interconnected cilia, and thick mesoglea. Other morphological features include definitive muscle cells, a nerve net, basal lamina, a sperm acrosome, and light-producing photocytes. Aspects of their development made them attractive to experimental embryologists as early as the 19th century. Recently, because of their role as an invasive species, studies on their role in ecology and fisheries-related fields have increased. Although the phylogenetic placement of ctenophores with respect to other animals has proven difficult, it is clear that, along with poriferans, placozoans, and cnidarians, ctenophores are one of the earliest diverging extant animal groups. It is important to determine if some of the complex features of ctenophores are examples of convergence or if they were lost in other animal branches. Because ctenophores are amenable to modern technical approaches, they could prove to be a highly useful emerging model.
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Affiliation(s)
- Kevin Pang
- Kewalo Marine Laboratory, University of Hawaii, Honolulu, HI 96813, USA
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Pang K, Martindale MQ. Developmental expression of homeobox genes in the ctenophore Mnemiopsis leidyi. Dev Genes Evol 2008; 218:307-19. [PMID: 18504608 DOI: 10.1007/s00427-008-0222-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Accepted: 04/14/2008] [Indexed: 11/28/2022]
Affiliation(s)
- Kevin Pang
- Kewalo Marine Laboratory, Pacific Biosciences Research Center, University of Hawaii, 41 Ahui Street, Honolulu, HI 96813, USA
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