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Turner RL. The Metameric Echinoderm. Integr Org Biol 2024; 6:obae005. [PMID: 38558855 PMCID: PMC10980344 DOI: 10.1093/iob/obae005] [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: 11/20/2023] [Revised: 01/10/2024] [Accepted: 02/29/2024] [Indexed: 04/04/2024] Open
Abstract
Animal phyla are distinguished by their body plans, the ways in which their bodies are organized. A distinction is made, for example, among phyla with bodies of many segments (metameric; e.g., annelids, arthropods, and chordates), others with completely unsegmented bodies (americ; e.g., flatworms and mollusks), and a few phyla with bodies of 2 or 3 regions (oligomeric; e.g., echinoderms and hemichordates). The conventional view of echinoderms as oligomeric coelomates adequately considers early development, but it fails to recognize the metameric body plan that develops in the juvenile rudiment and progresses during indeterminate adult growth. As in the 3 phyla traditionally viewed to be metameric (annelids, arthropods, and chordates), metamery, or metamerism, in echinoderms occurs by (1) subterminal budding of (2) serially repeated components of (3) mesodermal origin. A major difference in most echinoderms is that metamery is expressed along multiple body axes, usually 5. The view of a metameric echinoderm might invite new discussions of metazoan body plans and new approaches to the study of morphogenesis, particularly in comparative treatments with annelids, arthropods, and chordates.
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Affiliation(s)
- R L Turner
- Department of Ocean Engineering and Marine Sciences, Florida Institute of Technology, Melbourne, FL 32901-6975, USA
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2
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Nanglu K, Cole SR, Wright DF, Souto C. Worms and gills, plates and spines: the evolutionary origins and incredible disparity of deuterostomes revealed by fossils, genes, and development. Biol Rev Camb Philos Soc 2023; 98:316-351. [PMID: 36257784 DOI: 10.1111/brv.12908] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 09/23/2022] [Accepted: 09/28/2022] [Indexed: 01/12/2023]
Abstract
Deuterostomes are the major division of animal life which includes sea stars, acorn worms, and humans, among a wide variety of ecologically and morphologically disparate taxa. However, their early evolution is poorly understood, due in part to their disparity, which makes identifying commonalities difficult, as well as their relatively poor early fossil record. Here, we review the available morphological, palaeontological, developmental, and molecular data to establish a framework for exploring the origins of this important and enigmatic group. Recent fossil discoveries strongly support a vermiform ancestor to the group Hemichordata, and a fusiform active swimmer as ancestor to Chordata. The diverse and anatomically bewildering variety of forms among the early echinoderms show evidence of both bilateral and radial symmetry. We consider four characteristics most critical for understanding the form and function of the last common ancestor to Deuterostomia: Hox gene expression patterns, larval morphology, the capacity for biomineralization, and the morphology of the pharyngeal region. We posit a deuterostome last common ancestor with a similar antero-posterior gene regulatory system to that found in modern acorn worms and cephalochordates, a simple planktonic larval form, which was later elaborated in the ambulacrarian lineage, the ability to secrete calcium minerals in a limited fashion, and a pharyngeal respiratory region composed of simple pores. This animal was likely to be motile in adult form, as opposed to the sessile origins that have been historically suggested. Recent debates regarding deuterostome monophyly as well as the wide array of deuterostome-affiliated problematica further suggest the possibility that those features were not only present in the last common ancestor of Deuterostomia, but potentially in the ur-bilaterian. The morphology and development of the early deuterostomes, therefore, underpin some of the most significant questions in the study of metazoan evolution.
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Affiliation(s)
- Karma Nanglu
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, USA
| | - Selina R Cole
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, 10th & Constitution Avenue NW, Washington, DC, 20560, USA.,Sam Noble Museum, University of Oklahoma, 2401 Chautauqua Avenue, Norman, OK, 73072, USA.,School of Geosciences, University of Oklahoma, 100 E Boyd Street, Norman, OK, 73019, USA
| | - David F Wright
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, 10th & Constitution Avenue NW, Washington, DC, 20560, USA.,Sam Noble Museum, University of Oklahoma, 2401 Chautauqua Avenue, Norman, OK, 73072, USA.,School of Geosciences, University of Oklahoma, 100 E Boyd Street, Norman, OK, 73019, USA
| | - Camilla Souto
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, 10th & Constitution Avenue NW, Washington, DC, 20560, USA.,School of Natural Sciences & Mathematics, Stockton University, 101 Vera King Farris Dr, Galloway, NJ, 08205, USA
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Sweet HC, Azriel G, Jaff N, Moser J, Riola TA, Ideman C, Barton M, Nelson J, Lenhart MM. Formation of Coelomic Cavities during Abbreviated Development of the Brittle Star Ophioplocus esmarki. THE BIOLOGICAL BULLETIN 2022; 243:283-298. [PMID: 36716487 DOI: 10.1086/721954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
AbstractIn brittle stars, the coelomic cavities that form during embryogenesis contribute to most of the internal organ systems of the juvenile. In the ancestral mode of development, the coelomic cavities begin with bilateral symmetry and play a minor role in the function of the ophiopluteus larva. However, the coelomic cavities undergo extensive changes during metamorphosis to set up the body systems of the juvenile brittle star. Many lineages of brittle stars have evolved life histories without the ophiopluteus larva. The non-feeding vitellaria larva has rapid development of juvenile structures. This work demonstrates the modifications to the origin and early development of the coelomic cavities in a vitellaria larva. Much of the archenteron forms an unpaired axocoel, hydrocoel, and somatocoel. The posterior-most portion of the archenteron forms the rudiment of the juvenile stomach. The right somatocoel and a portion of the left somatocoel form as invaginations of the lateral ectoderm. Later morphogenesis of the axocoel, the hydrocoel, and the two somatocoels is similar to what has been shown for brittle stars with an ophiopluteus larva. Confocal microscopy and three-dimensional modeling were used to show new details for the later morphogenesis of the coelomic cavities. The stone canal originates as an outgrowth of the hydrocoel between lobes 4 and 5. The hydrocoel lobes have minimal migration after they meet to complete the ring canal. The right somatocoel contributes to a component of the axial complex and perihemal system. A detailed description is given for how the left somatocoel contributes to multiple organ systems.
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Thompson JR, Paganos P, Benvenuto G, Arnone MI, Oliveri P. Post-metamorphic skeletal growth in the sea urchin Paracentrotus lividus and implications for body plan evolution. EvoDevo 2021; 12:3. [PMID: 33726833 PMCID: PMC7968366 DOI: 10.1186/s13227-021-00174-1] [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: 12/08/2020] [Accepted: 03/02/2021] [Indexed: 12/13/2022] Open
Abstract
Background Understanding the molecular and cellular processes that underpin animal development are crucial for understanding the diversity of body plans found on the planet today. Because of their abundance in the fossil record, and tractability as a model system in the lab, skeletons provide an ideal experimental model to understand the origins of animal diversity. We herein use molecular and cellular markers to understand the growth and development of the juvenile sea urchin (echinoid) skeleton. Results We developed a detailed staging scheme based off of the first ~ 4 weeks of post-metamorphic life of the regular echinoid Paracentrotus lividus. We paired this scheme with immunohistochemical staining for neuronal, muscular, and skeletal tissues, and fluorescent assays of skeletal growth and cell proliferation to understand the molecular and cellular mechanisms underlying skeletal growth and development of the sea urchin body plan. Conclusions Our experiments highlight the role of skeletogenic proteins in accretionary skeletal growth and cell proliferation in the addition of new metameric tissues. Furthermore, this work provides a framework for understanding the developmental evolution of sea urchin body plans on macroevolutionary timescales. Supplementary Information The online version contains supplementary material available at 10.1186/s13227-021-00174-1.
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Affiliation(s)
- Jeffrey R Thompson
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK. .,UCL Center for Life's Origins and Evolution, London, UK.
| | - Periklis Paganos
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | | | - Maria Ina Arnone
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Paola Oliveri
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK. .,UCL Center for Life's Origins and Evolution, London, UK.
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5
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Byrne M, Koop D, Strbenac D, Cisternas P, Balogh R, Yang JYH, Davidson PL, Wray G. Transcriptomic analysis of sea star development through metamorphosis to the highly derived pentameral body plan with a focus on neural transcription factors. DNA Res 2021; 27:5825731. [PMID: 32339242 PMCID: PMC7315356 DOI: 10.1093/dnares/dsaa007] [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] [Received: 11/11/2019] [Accepted: 04/20/2020] [Indexed: 12/13/2022] Open
Abstract
The Echinodermata is characterized by a secondarily evolved pentameral body plan. While the evolutionary origin of this body plan has been the subject of debate, the molecular mechanisms underlying its development are poorly understood. We assembled a de novo developmental transcriptome from the embryo through metamorphosis in the sea star Parvulastra exigua. We use the asteroid model as it represents the basal-type echinoderm body architecture. Global variation in gene expression distinguished the gastrula profile and showed that metamorphic and juvenile stages were more similar to each other than to the pre-metamorphic stages, pointing to the marked changes that occur during metamorphosis. Differential expression and gene ontology (GO) analyses revealed dynamic changes in gene expression throughout development and the transition to pentamery. Many GO terms enriched during late metamorphosis were related to neurogenesis and signalling. Neural transcription factor genes exhibited clusters with distinct expression patterns. A suite of these genes was up-regulated during metamorphosis (e.g. Pax6, Eya, Hey, NeuroD, FoxD, Mbx, and Otp). In situ hybridization showed expression of neural genes in the CNS and sensory structures. Our results provide a foundation to understand the metamorphic transition in echinoderms and the genes involved in development and evolution of pentamery.
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Affiliation(s)
- Maria Byrne
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Demian Koop
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Dario Strbenac
- School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia
| | - Paula Cisternas
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Regina Balogh
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Jean Yee Hwa Yang
- School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia
| | | | - Gregory Wray
- Department of Biology, Duke University, Durham, NC 27708, USA.,Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
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6
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Byrne M, Koop D, Strbenac D, Cisternas P, Yang JYH, Davidson PL, Wray G. Transcriptomic analysis of Nodal - and BMP- associated genes during development to the juvenile seastar in Parvulastra exigua (Asterinidae). Mar Genomics 2021; 59:100857. [PMID: 33676872 DOI: 10.1016/j.margen.2021.100857] [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: 11/18/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 10/22/2022]
Abstract
The molecular mechanisms underlying development of the pentameral body of adult echinoderms are poorly understood but are important to solve with respect to evolution of a unique body plan that contrasts with the bilateral body plan of other deuterostomes. As Nodal and BMP2/4 signalling is involved in axis formation in larvae and development of the echinoderm body plan, we used the developmental transcriptome generated for the asterinid seastar Parvulastra exigua to investigate the temporal expression patterns of Nodal and BMP2/4 genes from the embryo and across metamorphosis to the juvenile. For echinoderms, the Asteroidea represents the basal-type body architecture with a distinct (separated) ray structure. Parvulastra exigua has lecithotrophic development forming the juvenile soon after gastrulation providing ready access to the developing adult stage. We identified 39 genes associated with the Nodal and BMP2/4 network in the P. exigua developmental transcriptome. Clustering analysis of these genes resulted in 6 clusters with similar temporal expression patterns across development. A co-expression analysis revealed genes that have similar expression profiles as Nodal and BMP2/4. These results indicated genes that may have a regulatory relationship in patterning morphogenesis of the juvenile seastar. Developmental RNA-seq analyses of Parvulastra exigua show changes in Nodal and BMP2/4 signalling genes across the metamorphic transition. We provide the foundation for detailed analyses of this cascade in the evolution of the unusual pentameral echinoderm body and its deuterostome affinities.
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Affiliation(s)
- Maria Byrne
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia.
| | - Demian Koop
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Dario Strbenac
- School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia
| | - Paula Cisternas
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Jean Yee Hwa Yang
- School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia
| | - Phillip L Davidson
- Department of Biology and Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - Gregory Wray
- Department of Biology and Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
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7
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Formery L, Orange F, Formery A, Yaguchi S, Lowe CJ, Schubert M, Croce JC. Neural anatomy of echinoid early juveniles and comparison of nervous system organization in echinoderms. J Comp Neurol 2020; 529:1135-1156. [PMID: 32841380 DOI: 10.1002/cne.25012] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/07/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022]
Abstract
The echinoderms are a phylum of marine deuterostomes characterized by the pentaradial (five fold) symmetry of their adult bodies. Due to this unusual body plan, adult echinoderms have long been excluded from comparative analyses aimed at understanding the origin and evolution of deuterostome nervous systems. Here, we investigated the neural anatomy of early juveniles of representatives of three of the five echinoderm classes: the echinoid Paracentrotus lividus, the asteroid Patiria miniata, and the holothuroid Parastichopus parvimensis. Using whole mount immunohistochemistry and confocal microscopy, we found that the nervous system of echinoid early juveniles is composed of three main structures: a basiepidermal nerve plexus, five radial nerve cords connected by a circumoral nerve ring, and peripheral nerves innervating the appendages. Our whole mount preparations further allowed us to obtain thorough descriptions of these structures and of several innervation patterns, in particular at the level of the appendages. Detailed comparisons of the echinoid juvenile nervous system with those of asteroid and holothuroid juveniles moreover supported a general conservation of the main neural structures in all three species, including at the level of the appendages. Our results support the previously proposed hypotheses for the existence of two neural units in echinoderms: one consisting of the basiepidermal nerve plexus to process sensory stimuli locally and one composed of the radial nerve cords and the peripheral nerves constituting a centralized control system. This study provides the basis for more in-depth comparisons of the echinoderm adult nervous system with those of other animals, in particular hemichordates and chordates, to address the long-standing controversies about deuterostome nervous system evolution.
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Affiliation(s)
- Laurent Formery
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Evolution of Intracellular Signaling in Development (EvoInSiDe), Sorbonne Université, CNRS, Villefranche-sur-Mer, France
| | - François Orange
- Centre Commun de Microscopie Appliquée (CCMA), Université Côte d'Azur, Nice, France
| | | | - Shunsuke Yaguchi
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Christopher J Lowe
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, USA
| | - Michael Schubert
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Evolution of Intracellular Signaling in Development (EvoInSiDe), Sorbonne Université, CNRS, Villefranche-sur-Mer, France
| | - Jenifer C Croce
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Evolution of Intracellular Signaling in Development (EvoInSiDe), Sorbonne Université, CNRS, Villefranche-sur-Mer, France
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8
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Byrne M. The Link between Autotomy and CNS Regeneration: Echinoderms as Non‐Model Species for Regenerative Biology. Bioessays 2020; 42:e1900219. [DOI: 10.1002/bies.201900219] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/19/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Maria Byrne
- School of Medical Sciences and School of Life and Environmental Sciences University of Sydney NSW 2006 Australia
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9
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Adachi S, Niimi I, Sakai Y, Sato F, Minokawa T, Urata M, Sehara-Fujisawa A, Kobayashi I, Yamaguchi M. Anteroposterior molecular registries in ectoderm of the echinus rudiment. Dev Dyn 2018; 247:1297-1307. [DOI: 10.1002/dvdy.24686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 10/03/2018] [Accepted: 10/21/2018] [Indexed: 01/01/2023] Open
Affiliation(s)
- Shinya Adachi
- Graduate School of Natural Science and Technology; Kanazawa University; Kakuma Kanazawa Japan
| | - Iyo Niimi
- Graduate School of Natural Science and Technology; Kanazawa University; Kakuma Kanazawa Japan
| | - Yui Sakai
- Graduate School of Natural Science and Technology; Kanazawa University; Kakuma Kanazawa Japan
| | - Fuminori Sato
- Department of Growth Regulation; Institute for Frontier Medical Sciences, Kyoto University; Sakyo-ku Kyoto Japan
| | - Takuya Minokawa
- Research Center for Marine Biology, Graduate School of Life Sciences; Tohoku University; Asamushi Aomori Japan
| | - Makoto Urata
- Noto Marine Laboratory, Institute of Natural and Environmental Technology; Kanazawa University; Noto Hosu Japan
| | - Atsuko Sehara-Fujisawa
- Department of Growth Regulation; Institute for Frontier Medical Sciences, Kyoto University; Sakyo-ku Kyoto Japan
| | - Isao Kobayashi
- Graduate School of Natural Science and Technology; Kanazawa University; Kakuma Kanazawa Japan
| | - Masaaki Yamaguchi
- Graduate School of Natural Science and Technology; Kanazawa University; Kakuma Kanazawa Japan
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10
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Koop D, Cisternas P, Morris VB, Strbenac D, Yang JYH, Wray GA, Byrne M. Nodal and BMP expression during the transition to pentamery in the sea urchin Heliocidaris erythrogramma: insights into patterning the enigmatic echinoderm body plan. BMC DEVELOPMENTAL BIOLOGY 2017; 17:4. [PMID: 28193178 PMCID: PMC5307799 DOI: 10.1186/s12861-017-0145-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 01/26/2017] [Indexed: 12/27/2022]
Abstract
BACKGROUND The molecular mechanisms underlying the development of the unusual echinoderm pentameral body plan and their likeness to mechanisms underlying the development of the bilateral plans of other deuterostomes are of interest in tracing body plan evolution. In this first study of the spatial expression of genes associated with Nodal and BMP2/4 signalling during the transition to pentamery in sea urchins, we investigate Heliocidaris erythrogramma, a species that provides access to the developing adult rudiment within days of fertilization. RESULTS BMP2/4, and the putative downstream genes, Six1/2, Eya, Tbx2/3 and Msx were expressed in the earliest morphological manifestation of pentamery during development, the five hydrocoele lobes. The formation of the vestibular ectoderm, the specialized region overlying the left coelom that forms adult ectoderm, involved the expression of putative Nodal target genes Chordin, Gsc and BMP2/4 and putative BMP2/4 target genes Dlx, Msx and Tbx. The expression of Nodal, Lefty and Pitx2 in the right ectoderm, and Pitx2 in the right coelom, was as previously observed in other sea urchins. CONCLUSION That genes associated with Nodal and BMP2/4 signalling are expressed in the hydrocoele lobes, indicates that they have a role in the developmental transition to pentamery, contributing to our understanding of how the most unusual body plan in the Bilateria may have evolved. We suggest that the Nodal and BMP2/4 signalling cascades might have been duplicated or split during the evolution to pentamery.
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Affiliation(s)
- Demian Koop
- School of Medical Science and Bosch Institute, The University of Sydney, Sydney, NSW 2006 Australia
| | - Paula Cisternas
- School of Medical Science and Bosch Institute, The University of Sydney, Sydney, NSW 2006 Australia
| | - Valerie B. Morris
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006 Australia
| | - Dario Strbenac
- School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006 Australia
| | - Jean Yee Hwa Yang
- School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006 Australia
| | - Gregory A. Wray
- Department of Biology and Center for Genomic and Computational Biology, Duke University, Durham, NC 27708 USA
| | - Maria Byrne
- School of Medical Science and Bosch Institute, The University of Sydney, Sydney, NSW 2006 Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006 Australia
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11
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Morris VB. Analysis of coelom development in the sea urchin Holopneustes purpurescens yielding a deuterostome body plan. Biol Open 2016; 5:348-58. [PMID: 26892238 PMCID: PMC4810744 DOI: 10.1242/bio.015925] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
An analysis of early coelom development in the echinoid Holopneustes purpurescens yields a deuterostome body plan that explains the disparity between the pentameral plan of echinoderms and the bilateral plans of chordates and hemichordates, the three major phyla of the monophyletic deuterostomes. The analysis shows an early separation into a medial hydrocoele and lateral coelomic mesoderm with an enteric channel between them before the hydrocoele forms the pentameral plan of five primary podia. The deuterostome body plan thus has a single axial or medial coelom and a pair of lateral coeloms, all surrounding an enteric channel, the gut channel. Applied to the phyla, the medial coelom is the hydrocoele in echinoderms, the notochord in chordates and the proboscis coelom in hemichordates: the lateral coeloms are the coelomic mesoderm in echinoderms, the paraxial mesoderm in chordates and the lateral coeloms in hemichordates. The plan fits frog and chick development and the echinoderm fossil record, and predicts genes involved in coelomogenesis as the source of deuterostome macroevolution. Summary: A common body plan for echinoderms, chordates and hemichordates resolves the apparent morphological disparity between the pentameral and the bilateral body plans of these major deuterostome phyla.
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Affiliation(s)
- Valerie B Morris
- School of Biological Sciences A12, University of Sydney, New South Wales 2006, Australia
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12
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Byrne M, Martinez P, Morris V. Evolution of a pentameral body plan was not linked to translocation of anterior Hox genes: the echinoderm HOX cluster revisited. Evol Dev 2016; 18:137-43. [DOI: 10.1111/ede.12172] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Maria Byrne
- Schools of Medical and Biological SciencesThe University of SydneySydneyNSW2006Australia
| | - Pedro Martinez
- Departament de GenèticaUniversitat de BarcelonaAv. Diagonal, 643Barcelona08028Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA)Passeig Lluís Companys, 23Barcelona08010Spain
| | - Valerie Morris
- School of Biological SciencesThe University of SydneySydneyNSW2006Australia
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13
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Abstract
A notochord is characteristic of developing chordates (which comprise amphioxus, tunicates and vertebrates), and, more arguably, is also found in some other animals. Although notochords have been well reviewed from a developmental genetic point of view, there has heretofore been no adequate survey of the dozen or so scenarios accounting for their evolutionary origin. Advances in molecular phylogenetics and developmental genetics have, on the one hand, failed to support many of these ideas (although, it is not impossible that some of these rejects may yet, at least in part, return to favor). On the other hand, current molecular approaches have actually stimulated the revival of two of the old proposals: first that the notochord is a novelty that arose in the chordates, and second that it is derived from a homologous structure, the axochord, that was present in annelid-like ancestors. In the long term, choosing whether the notochord is a chordate novelty or a legacy from an ancient annelid (or perhaps an evolutionary derivative from precursors yet to be proposed) will probably require descriptions of gene regulatory networks involved in the development of notochords and notochord-like structures in a wide spectrum of animals. For now, one-way forward will be studies of all aspects of the biology of enteropneust hemichordates, a group widely thought to be the key to understanding the evolutionary origin of the chordates.
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Affiliation(s)
- Giovanni Annona
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | - Nicholas D Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093 USA
| | - Salvatore D'Aniello
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
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14
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Lacalli T. Echinoderm conundrums: Hox genes, heterochrony, and an excess of mouths. EvoDevo 2014; 5:46. [PMID: 25598963 PMCID: PMC4297399 DOI: 10.1186/2041-9139-5-46] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 11/27/2014] [Indexed: 12/02/2022] Open
Abstract
Two issues relating to the translocation of anterior Hox genes in echinoderms to the 5' end of the Hox cluster are discussed: i) that developmental changes associated with fixation to the substratum have led to an acceleration of mesodermal development relative to that of ectoderm, resulting in a mismatch of anteroposterior registry between the two tissues and a larger role for mesoderm in patterning control, and ii) whether this helps explain the ability of some echinoderms to form separate mouths at different locations, one for the larva and one for the juvenile rudiment. Freeing the mesoderm from ectodermal influences may have encouraged morphogenetic innovation, paralleling the situation in tunicates, where an early genomic (or genomic and developmental) change has allowed the body to evolve in novel ways.
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Affiliation(s)
- Thurston Lacalli
- Biology Department, University of Victoria, Victoria, BC V8W-3N5 Canada
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Cannon JT, Kocot KM, Waits DS, Weese DA, Swalla BJ, Santos SR, Halanych KM. Phylogenomic resolution of the hemichordate and echinoderm clade. Curr Biol 2014; 24:2827-32. [PMID: 25454590 DOI: 10.1016/j.cub.2014.10.016] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/06/2014] [Accepted: 10/07/2014] [Indexed: 02/01/2023]
Abstract
Ambulacraria, comprising Hemichordata and Echinodermata, is closely related to Chordata, making it integral to understanding chordate origins and polarizing chordate molecular and morphological characters. Unfortunately, relationships within Hemichordata and Echinodermata have remained unresolved, compromising our ability to extrapolate findings from the most closely related molecular and developmental models outside of Chordata (e.g., the acorn worms Saccoglossus kowalevskii and Ptychodera flava and the sea urchin Strongylocentrotus purpuratus). To resolve long-standing phylogenetic issues within Ambulacraria, we sequenced transcriptomes for 14 hemichordates as well as 8 echinoderms and complemented these with existing data for a total of 33 ambulacrarian operational taxonomic units (OTUs). Examination of leaf stability values revealed rhabdopleurid pterobranchs and the enteropneust Stereobalanus canadensis were unstable in placement; therefore, analyses were also run without these taxa. Analyses of 185 genes resulted in reciprocal monophyly of Enteropneusta and Pterobranchia, placed the deep-sea family Torquaratoridae within Ptychoderidae, and confirmed the position of ophiuroid brittle stars as sister to asteroid sea stars (the Asterozoa hypothesis). These results are consistent with earlier perspectives concerning plesiomorphies of Ambulacraria, including pharyngeal gill slits, a single axocoel, and paired hydrocoels and somatocoels. The resolved ambulacrarian phylogeny will help clarify the early evolution of chordate characteristics and has implications for our understanding of major fossil groups, including graptolites and somasteroideans.
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Affiliation(s)
- Johanna T Cannon
- Department of Biological Sciences and Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA; Department of Zoology, Naturhistoriska Riksmuseet, 104 05 Stockholm, Sweden; Friday Harbor Laboratories, University of Washington, 620 University Road, Friday Harbor, WA 98250, USA.
| | - Kevin M Kocot
- Department of Biological Sciences and Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA; School of Biological Sciences, University of Queensland, Brisbane, QLD 4072, Australia; Friday Harbor Laboratories, University of Washington, 620 University Road, Friday Harbor, WA 98250, USA
| | - Damien S Waits
- Department of Biological Sciences and Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA
| | - David A Weese
- Department of Biological Sciences and Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA; Department of Biological and Environmental Sciences, Georgia College and State University, Milledgeville, GA 31061, USA
| | - Billie J Swalla
- Friday Harbor Laboratories, University of Washington, 620 University Road, Friday Harbor, WA 98250, USA
| | - Scott R Santos
- Department of Biological Sciences and Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA
| | - Kenneth M Halanych
- Department of Biological Sciences and Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA; Friday Harbor Laboratories, University of Washington, 620 University Road, Friday Harbor, WA 98250, USA.
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Szabó R, Ferrier DEK. Cell proliferation dynamics in regeneration of the operculum head appendage in the annelid Pomatoceros lamarckii. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2014; 322:257-68. [PMID: 24799350 DOI: 10.1002/jez.b.22572] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/28/2014] [Accepted: 04/03/2014] [Indexed: 12/20/2022]
Abstract
Regeneration of lost or damaged appendages is a widespread and ecologically important ability in the animal kingdom, and also of great significance to developing regenerative medicine. The operculum of serpulid polychaetes is one among the many diverse appendages found in the lophotrochozoan superphylum, a clade hitherto understudied with respect to the mechanisms of appendage regeneration. In this study, we establish the normal time course of opercular regeneration in the serpulid Pomatoceros lamarckii and describe cell proliferation patterns in the regenerating opercular filament. The P. lamarckii operculum regenerates through a rapid and consistent series of morphogenetic events. Based on 5-bromo-2'-deoxyuridine (BrdU) labeling and anti-phosphohistone H3 immunohistochemistry, opercular regeneration appears to be a mixture of an early morphallactic stage, and a later phase characterized by widespread proliferative activity within the opercular filament. Tracking residual pigmentation suggests that the distal part of the stump gives rise to the most distal structures of the operculum via morphallactic remodeling, whereas more proximal structures are derived from the proximal stump. Our work underscores the diversity of regenerative strategies employed by animals and introduces P. lamarckii as an emerging model of appendage regeneration.
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Affiliation(s)
- Réka Szabó
- The Scottish Oceans Institute, Gatty Marine Laboratory, University of St Andrews, East Sands, St Andrews, Scotland, United Kingdom
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Tsuchimoto J, Yamaguchi M. Hoxexpression in the direct-type developing sand dollarPeronella japonica. Dev Dyn 2014; 243:1020-9. [DOI: 10.1002/dvdy.24135] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 02/27/2014] [Accepted: 02/28/2014] [Indexed: 12/21/2022] Open
Affiliation(s)
- Jun Tsuchimoto
- Division of Life Science; Graduate School of Natural Science and Technology, Kanazawa University; Kanazawa Japan
- Institute for Molecular Science of Medicine, Aichi Medical University; Nagakute Japan
| | - Masaaki Yamaguchi
- Division of Life Science; Graduate School of Natural Science and Technology, Kanazawa University; Kanazawa Japan
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Morris VB, Byrne M. Oral-aboral identity displayed in the expression of HpHox3 and HpHox11/13 in the adult rudiment of the sea urchin Holopneustes purpurescens. Dev Genes Evol 2013; 224:1-11. [PMID: 24129745 DOI: 10.1007/s00427-013-0457-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 09/19/2013] [Indexed: 01/29/2023]
Abstract
Hox genes are noted for their roles in specifying axial identity in bilateral forms. In the radial echinoderms, the axis whose identity Hox genes might specify remains unclear. From the expression of Hox genes in the development of the sea urchin Holopneustes purpurescens reported here and that reported previously, we clarify the axis that might be specified by Hox genes in echinoderms. The expression of HpHox11/13 here is described at three developmental stages. The expression is around the rim of the blastopore in gastrulae, in the archenteron wall and adjacent mesoderm in early vestibula larvae, and in a patch of mesoderm close to the archenteron wall in later vestibula larvae. The retained expression of HpHox11/13 in the patch of mesoderm in the later vestibula larvae is, we suggest, indicative of a posterior or an aboral growth zone. The expression of HpHox3 at the echinoid-rudiment stage, in contrast, is in oral mesoderm beneath the epineural folds, concentrated in sites where the first three adult spines form. With the expression of HpHox5 and HpHox11/13 reported previously, the expressions here support the role of Hox genes in specifying oral-aboral identity in echinoderms. How such specification and a posterior growth zone add support to a concept of the structural homology between echinoderms and chordates is discussed.
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Affiliation(s)
- Valerie B Morris
- School of Biological Sciences A12, University of Sydney, NSW, 2006, Australia,
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