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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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2
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Ettensohn CA, Guerrero-Santoro J, Khor JM. Lessons from a transcription factor: Alx1 provides insights into gene regulatory networks, cellular reprogramming, and cell type evolution. Curr Top Dev Biol 2022; 146:113-148. [PMID: 35152981 DOI: 10.1016/bs.ctdb.2021.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The skeleton-forming cells of sea urchins and other echinoderms have been studied by developmental biologists as models of cell specification and morphogenesis for many decades. The gene regulatory network (GRN) deployed in the embryonic skeletogenic cells of euechinoid sea urchins is one of the best understood in any developing animal. Recent comparative studies have leveraged the information contained in this GRN, bringing renewed attention to the diverse patterns of skeletogenesis within the phylum and the evolutionary basis for this diversity. The homeodomain-containing transcription factor, Alx1, was originally shown to be a core component of the skeletogenic GRN of the sea urchin embryo. Alx1 has since been found to be key regulator of skeletal cell identity throughout the phylum. As such, Alx1 is currently serving as a lens through which multiple developmental processes are being investigated. These include not only GRN organization and evolution, but also cell reprogramming, cell type evolution, and the gene regulatory control of morphogenesis. This review summarizes our current state of knowledge concerning Alx1 and highlights the insights it is yielding into these important developmental and evolutionary processes.
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Affiliation(s)
- Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States.
| | | | - Jian Ming Khor
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States
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3
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Erkenbrack EM, Thompson JR. Cell type phylogenetics informs the evolutionary origin of echinoderm larval skeletogenic cell identity. Commun Biol 2019; 2:160. [PMID: 31069269 PMCID: PMC6499829 DOI: 10.1038/s42003-019-0417-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 04/04/2019] [Indexed: 01/19/2023] Open
Abstract
The multiplicity of cell types comprising multicellular organisms begs the question as to how cell type identities evolve over time. Cell type phylogenetics informs this question by comparing gene expression of homologous cell types in distantly related taxa. We employ this approach to inform the identity of larval skeletogenic cells of echinoderms, a clade for which there are phylogenetically diverse datasets of spatial gene expression patterns. We determined ancestral spatial expression patterns of alx1, ets1, tbr, erg, and vegfr, key components of the skeletogenic gene regulatory network driving identity of the larval skeletogenic cell. Here we show ancestral state reconstructions of spatial gene expression of extant eleutherozoan echinoderms support homology and common ancestry of echinoderm larval skeletogenic cells. We propose larval skeletogenic cells arose in the stem lineage of eleutherozoans during a cell type duplication event that heterochronically activated adult skeletogenic cells in a topographically distinct tissue in early development.
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Affiliation(s)
- Eric M. Erkenbrack
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511 USA
- Yale Systems Biology Institute, Yale University, West Haven, CT 06516 USA
| | - Jeffrey R. Thompson
- Department of Geosciences, Baylor University, Waco, TX 76706 USA
- Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089-0740 USA
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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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5
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Shashikant T, Khor JM, Ettensohn CA. From genome to anatomy: The architecture and evolution of the skeletogenic gene regulatory network of sea urchins and other echinoderms. Genesis 2018; 56:e23253. [PMID: 30264451 PMCID: PMC6294693 DOI: 10.1002/dvg.23253] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/14/2018] [Accepted: 09/23/2018] [Indexed: 01/19/2023]
Abstract
The skeletogenic gene regulatory network (GRN) of sea urchins and other echinoderms is one of the most intensively studied transcriptional networks in any developing organism. As such, it serves as a preeminent model of GRN architecture and evolution. This review summarizes our current understanding of this developmental network. We describe in detail the most comprehensive model of the skeletogenic GRN, one developed for the euechinoid sea urchin Strongylocentrotus purpuratus, including its initial deployment by maternal inputs, its elaboration and stabilization through regulatory gene interactions, and its control of downstream effector genes that directly drive skeletal morphogenesis. We highlight recent comparative studies that have leveraged the euechinoid GRN model to examine the evolution of skeletogenic programs in diverse echinoderms, studies that have revealed both conserved and divergent features of skeletogenesis within the phylum. Last, we summarize the major insights that have emerged from analysis of the structure and evolution of the echinoderm skeletogenic GRN and identify key, unresolved questions as a guide for future work.
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Affiliation(s)
- Tanvi Shashikant
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Jian Ming Khor
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
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Minokawa T. Comparative studies on the skeletogenic mesenchyme of echinoids. Dev Biol 2017; 427:212-218. [PMID: 27856261 DOI: 10.1016/j.ydbio.2016.11.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 10/25/2016] [Accepted: 11/14/2016] [Indexed: 11/16/2022]
Abstract
Skeletogenic mesenchyme cells in echinoids are suitable for studying developmental mechanisms, and have been used extensively. Most of these studies have been performed on species in the order Camarodonta, which are modern echinoids (subclass Euechinoidea) and are considered "model" echinoid species. In contrast, species belonging to other orders are studied less frequently, especially investigations of their molecular developmental biology such as gene regulatory networks. Recent studies on mesenchyme development in non-camarodont species suggest that these species are potential sources of comparative information to elucidate the mechanisms underlying skeletogenic mesenchyme development. In this review, the importance of using comparative data to understand development and evolution is discussed.
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Affiliation(s)
- Takuya Minokawa
- Research Center for Marine Biology, Graduate School of Life Sciences, Tohoku University, 9 Sakamoto, Asamushi, Aomori, Aomori 039-3501, Japan.
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7
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Erkenbrack EM, Petsios E. A Conserved Role for VEGF Signaling in Specification of Homologous Mesenchymal Cell Types Positioned at Spatially Distinct Developmental Addresses in Early Development of Sea Urchins. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2017; 328:423-432. [PMID: 28544452 DOI: 10.1002/jez.b.22743] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/04/2017] [Accepted: 04/05/2017] [Indexed: 11/06/2022]
Abstract
Comparative studies of early development in echinoderms are revealing the tempo and mode of alterations to developmental gene regulatory networks and to the cell types they specify. In euechinoid sea urchins, skeletogenic mesenchyme (SM) ingresses prior to gastrulation at the vegetal pole and aligns into a ring-like array with two bilateral pockets of cells, the sites where spiculogenesis will later occur. In cidaroid sea urchins, the anciently diverged sister clade to euechinoid sea urchins, a homologous SM cell type ingresses later in development, after gastrulation has commenced, and consequently at a distinct developmental address. Thus, a heterochronic shift of ingression of the SM cell type occurred in one of the echinoid lineages. In euechinoids, specification and migration of SM are facilitated by vascular endothelial growth factor (VEGF) signaling. We describe spatiotemporal expression of vegf and vegfr and experimental manipulations targeting VEGF signaling in the cidaroid Eucidaris tribuloides. Spatially, vegf and vegfr mRNA localizes similarly as in euechinoids, suggesting conserved deployment in echinoids despite their spatially distinct development addresses of ingression. Inhibition of VEGF signaling in E. tribuloides suggests its role in SM specification is conserved in echinoids. Temporal discrepancies between the onset of vegf expression and SM ingression likely result in previous observations of SM "random wandering" behavior. Our results indicate that, although the SM cell type in echinoids ingresses into distinct developmental landscapes, it retains a signaling mechanism that restricts their spatial localization to a conserved developmental address where spiculogenesis later occurs.
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Affiliation(s)
- Eric M Erkenbrack
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California.,Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut
| | - Elizabeth Petsios
- Department of Earth Sciences, University of Southern California, Los Angeles, California
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Cary GA, Hinman VF. Echinoderm development and evolution in the post-genomic era. Dev Biol 2017; 427:203-211. [PMID: 28185788 DOI: 10.1016/j.ydbio.2017.02.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 02/04/2017] [Accepted: 02/06/2017] [Indexed: 01/01/2023]
Abstract
The highly recognizable animals within the phylum Echinodermata encompass an enormous disparity of adult and larval body plans. The extensive knowledge of sea urchin development has culminated in the description of the exquisitely detailed gene regulatory network (GRN) that governs the specification of various embryonic territories. This information provides a unique opportunity for comparative studies in other echinoderm taxa to understand the evolution and developmental mechanisms underlying body plan change. This review focuses on recent work that has utilized new genomic resources and systems-level experiments to address questions of evolutionary developmental biology. In particular, we synthesize the results of several recent studies from various echinoderm classes that have explored the development and evolution of the larval skeleton, which is a major feature that distinguishes the two predominant larval subtypes within the Phylum. We specifically examine the ways in which GRNs can evolve, either through cis regulatory and/or protein-level changes in transcription factors. We also examine recent work comparing evolution across shorter time scales that occur within and between species of sea urchin, and highlight the kinds of questions that can be addressed by these comparisons. The advent of new genomic and transcriptomic datasets in additional species from all classes of echinoderm will continue to empower the use of these taxa for evolutionary developmental studies.
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Affiliation(s)
- Gregory A Cary
- Department of Biological Sciences, Carnegie Mellon University, Mellon Institute, 4400 Fifth Ave, Pittsburgh, PA 15213, United States
| | - Veronica F Hinman
- Department of Biological Sciences, Carnegie Mellon University, Mellon Institute, 4400 Fifth Ave, Pittsburgh, PA 15213, United States.
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