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Liu Y, Carlisle E, Zhang H, Yang B, Steiner M, Shao T, Duan B, Marone F, Xiao S, Donoghue PCJ. Saccorhytus is an early ecdysozoan and not the earliest deuterostome. Nature 2022; 609:541-546. [PMID: 35978194 DOI: 10.1038/s41586-022-05107-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 07/13/2022] [Indexed: 11/09/2022]
Abstract
The early history of deuterostomes, the group composed of the chordates, echinoderms and hemichordates1, is still controversial, not least because of a paucity of stem representatives of these clades2-5. The early Cambrian microscopic animal Saccorhytus coronarius was interpreted as an early deuterostome on the basis of purported pharyngeal openings, providing evidence for a meiofaunal ancestry6 and an explanation for the temporal mismatch between palaeontological and molecular clock timescales of animal evolution6-8. Here we report new material of S. coronarius, which is reconstructed as a millimetric and ellipsoidal meiobenthic animal with spinose armour and a terminal mouth but no anus. Purported pharyngeal openings in support of the deuterostome hypothesis6 are shown to be taphonomic artefacts. Phylogenetic analyses indicate that S. coronarius belongs to total-group Ecdysozoa, expanding the morphological disparity and ecological diversity of early Cambrian ecdysozoans.
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Affiliation(s)
- Yunhuan Liu
- School of Earth Science and Resources, Chang'an University, Xi'an, China
| | - Emily Carlisle
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, UK
| | - Huaqiao Zhang
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing, China.
| | - Ben Yang
- MNR Key Laboratory of Stratigraphy and Palaeontology, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China
| | - Michael Steiner
- College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, China.,Department of Earth Sciences, Freie Universität Berlin, Berlin, Germany
| | - Tiequan Shao
- School of Earth Science and Resources, Chang'an University, Xi'an, China
| | - Baichuan Duan
- Key Laboratory of Marine Geology and Metallogeny, First Institute of Oceanography, Ministry of Natural Resource, Qingdao, China
| | - Federica Marone
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - Shuhai Xiao
- Department of Geosciences, Virginia Tech, Blacksburg, VA, USA.
| | - Philip C J Donoghue
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, UK.
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2
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Avian M, Mancini L, Voltolini M, Bonnet D, Dreossi D, Macaluso V, Pillepich N, Prieto L, Ramšak A, Terlizzi A, Motta G. A novel endocast technique providing a 3D quantitative analysis of the gastrovascular system in Rhizostoma pulmo: An unexpected through-gut in cnidaria. PLoS One 2022; 17:e0272023. [PMID: 35925896 PMCID: PMC9352040 DOI: 10.1371/journal.pone.0272023] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 07/11/2022] [Indexed: 12/03/2022] Open
Abstract
The investigation of jellyfish gastrovascular systems mainly focused on stain injections and dissections, negatively affected by thickness and opacity of the mesoglea. Therefore, descriptions are incomplete and data about tridimensional structures are scarce. In this work, morphological and functional anatomy of the gastrovascular system of Rhizostoma pulmo (Macri 1778) was investigated in detail with innovative techniques: resin endocasts and 3D X-ray computed microtomography. The gastrovascular system consists of a series of branching canals ending with numerous openings within the frilled margins of the oral arms. Canals presented a peculiar double hemi-canal structure with a medial adhesion area which separates centrifugal and centripetal flows. The inward flow involves only the “mouth” openings on the internal wing of the oral arm and relative hemi-canals, while the outward flow involves only the two outermost wings’ hemi-canals and relative “anal” openings on the external oral arm. The openings differentiation recalls the functional characteristics of a through-gut apparatus. We cannot define the gastrovascular system in Rhizostoma pulmo as a traditional through-gut, rather an example of adaptive convergence, that partially invalidates the paradigm of a single oral opening with both the uptake and excrete function.
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Affiliation(s)
- Massimo Avian
- Department of Life Science, University of Trieste, Trieste, Italy
- * E-mail:
| | - Lucia Mancini
- Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, Italy
| | - Marco Voltolini
- Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, Italy
| | - Delphine Bonnet
- MARBEC, Université de Montpellier, CNRS, Ifremer, IRD, Montpellier, France
| | - Diego Dreossi
- Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, Italy
| | - Vanessa Macaluso
- Department of Life Science, University of Trieste, Trieste, Italy
| | - Nicole Pillepich
- Department of Life Science, University of Trieste, Trieste, Italy
| | - Laura Prieto
- Group Ecosystem Oceanography, Department of Ecology and Coastal Management, Instituto de Ciencias Marinas de Andalucia (CSIC), Cádiz, Spain
| | - Andreja Ramšak
- National Institute of Biology, Marine Biology Station, Piran, Slovenia
| | - Antonio Terlizzi
- Department of Life Science, University of Trieste, Trieste, Italy
- Department of Integrative Marine Ecology (EMI), Stazione Zoologica Anton Dohrn, Napoli, Italy
| | - Gregorio Motta
- Department of Life Science, University of Trieste, Trieste, Italy
- Department of Integrative Marine Ecology (EMI), Stazione Zoologica Anton Dohrn, Napoli, Italy
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Schulreich SM, Salamanca-Díaz DA, Zieger E, Calcino AD, Wanninger A. A mosaic of conserved and novel modes of gene expression and morphogenesis in mesoderm and muscle formation of a larval bivalve. ORG DIVERS EVOL 2022; 22:893-913. [PMID: 36398106 PMCID: PMC9649484 DOI: 10.1007/s13127-022-00569-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/26/2022] [Indexed: 10/17/2022]
Abstract
The mesoderm gives rise to several key morphological features of bilaterian animals including endoskeletal elements and the musculature. A number of regulatory genes involved in mesoderm and/or muscle formation (e.g., Brachyury (Bra), even-skipped (eve), Mox, myosin II heavy chain (mhc)) have been identified chiefly from chordates and the ecdysozoans Drosophila and Caenorhabditis elegans, but data for non-model protostomes, especially those belonging to the ecdysozoan sister clade, Lophotrochozoa (e.g., flatworms, annelids, mollusks), are only beginning to emerge. Within the lophotrochozoans, Mollusca constitutes the most speciose and diverse phylum. Interestingly, however, information on the morphological and molecular underpinnings of key ontogenetic processes such as mesoderm formation and myogenesis remains scarce even for prominent molluscan sublineages such as the bivalves. Here, we investigated myogenesis and developmental expression of Bra, eve, Mox, and mhc in the quagga mussel Dreissena rostriformis, an invasive freshwater bivalve and an emerging model in invertebrate evodevo. We found that all four genes are expressed during mesoderm formation, but some show additional, individual sites of expression during ontogeny. While Mox and mhc are involved in early myogenesis, eve is also expressed in the embryonic shell field and Bra is additionally present in the foregut. Comparative analysis suggests that Mox has an ancestral role in mesoderm and possibly muscle formation in bilaterians, while Bra and eve are conserved regulators of mesoderm development of nephrozoans (protostomes and deuterostomes). The fully developed Dreissena veliger larva shows a highly complex muscular architecture, supporting a muscular ground pattern of autobranch bivalve larvae that includes at least a velum muscle ring, three or four pairs of velum retractors, one or two pairs of larval retractors, two pairs of foot retractors, a pedal plexus, possibly two pairs of mantle retractors, and the muscles of the pallial line, as well as an anterior and a posterior adductor. As is typical for their molluscan kin, remodelling and loss of prominent larval features such as the velum musculature and various retractor systems appear to be also common in bivalves. Supplementary information The online version contains supplementary material available at 10.1007/s13127-022-00569-5.
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Affiliation(s)
- Stephan M. Schulreich
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - David A. Salamanca-Díaz
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Elisabeth Zieger
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Andrew D. Calcino
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Andreas Wanninger
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
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de Oliveira AL, Mitchell J, Girguis P, Bright M. Novel insights on obligate symbiont lifestyle and adaptation to chemosynthetic environment as revealed by the giant tubeworm genome. Mol Biol Evol 2021; 39:6454105. [PMID: 34893862 PMCID: PMC8789280 DOI: 10.1093/molbev/msab347] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The mutualism between the giant tubeworm Riftia pachyptila and its endosymbiont Candidatus Endoriftia persephone has been extensively researched over the past 40 years. However, the lack of the host whole genome information has impeded the full comprehension of the genotype/phenotype interface in Riftia. Here we described the high-quality draft genome of Riftia, its complete mitogenome, and tissue-specific transcriptomic data. The Riftia genome presents signs of reductive evolution, with gene family contractions exceeding expansions. Expanded gene families are related to sulphur metabolism, detoxification, anti-oxidative stress, oxygen transport, immune system, and lysosomal digestion, reflecting evolutionary adaptations to the vent environment and endosymbiosis. Despite the derived body plan, the developmental gene repertoire in the gutless tubeworm is extremely conserved with the presence of a near intact and complete Hox cluster. Gene expression analyses establishes that the trophosome is a multi-functional organ marked by intracellular digestion of endosymbionts, storage of excretory products and haematopoietic functions. Overall, the plume and gonad tissues both in contact to the environment harbour highly expressed genes involved with cell cycle, programmed cell death, and immunity indicating a high cell turnover and defence mechanisms against pathogens. We posit that the innate immune system plays a more prominent role into the establishment of the symbiosis during the infection in the larval stage, rather than maintaining the symbiostasis in the trophosome. This genome bridges four decades of physiological research in Riftia, whilst simultaneously provides new insights into the development, whole organism functions and evolution in the giant tubeworm.
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Affiliation(s)
| | - Jessica Mitchell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Peter Girguis
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Monika Bright
- Department of Functional and Evolutionary Ecology, University of Vienna, Austria
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5
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Generation of a Microsporidia Species Attribute Database and Analysis of the Extensive Ecological and Phenotypic Diversity of Microsporidia. mBio 2021; 12:e0149021. [PMID: 34182782 PMCID: PMC8262960 DOI: 10.1128/mbio.01490-21] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microsporidia are a large group of fungus-related obligate intracellular parasites. Though many microsporidia species have been identified over the past 160 years, depiction of the full diversity of this phylum is lacking. To systematically describe the characteristics of these parasites, we created a database of 1,440 species and their attributes, including the hosts they infect and spore characteristics. We find that microsporidia have been reported to infect 16 metazoan and 4 protozoan phyla, with smaller phyla being underrepresented. Most species are reported to infect only a single host, but those that are generalists are also more likely to infect a broader set of host tissues. Strikingly, polar tubes are threefold longer in species that infect tissues besides the intestine, suggesting that polar tube length is a determinant of tissue specificity. Phylogenetic analysis revealed four clades which each contain microsporidia that infect hosts from all major habitats. Although related species are more likely to infect similar hosts, we observe examples of changes in host specificity and convergent evolution. Taken together, our results show that microsporidia display vast diversity in their morphology and the hosts they infect, illustrating the flexibility of these parasites to evolve new traits.
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Kraus Y, Chevalier S, Houliston E. Cell shape changes during larval body plan development in Clytia hemisphaerica. Dev Biol 2020; 468:59-79. [DOI: 10.1016/j.ydbio.2020.09.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 09/04/2020] [Accepted: 09/19/2020] [Indexed: 12/21/2022]
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Zhong Y, Herrera-Úbeda C, Garcia-Fernàndez J, Li G, Holland PWH. Mutation of amphioxus Pdx and Cdx demonstrates conserved roles for ParaHox genes in gut, anus and tail patterning. BMC Biol 2020; 18:68. [PMID: 32546156 PMCID: PMC7296684 DOI: 10.1186/s12915-020-00796-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 05/19/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The homeobox genes Pdx and Cdx are widespread across the animal kingdom and part of the small ParaHox gene cluster. Gene expression patterns suggest ancient roles for Pdx and Cdx in patterning the through-gut of bilaterian animals although functional data are available for few lineages. To examine evolutionary conservation of Pdx and Cdx gene functions, we focus on amphioxus, small marine animals that occupy a pivotal position in chordate evolution and in which ParaHox gene clustering was first reported. RESULTS Using transcription activator-like effector nucleases (TALENs), we engineer frameshift mutations in the Pdx and Cdx genes of the amphioxus Branchiostoma floridae and establish mutant lines. Homozygous Pdx mutants have a defect in amphioxus endoderm, manifest as loss of a midgut region expressing endogenous GFP. The anus fails to open in homozygous Cdx mutants, which also have defects in posterior body extension and epidermal tail fin development. Treatment with an inverse agonist of retinoic acid (RA) signalling partially rescues the axial and tail fin phenotypes indicating they are caused by increased RA signalling. Gene expression analyses and luciferase assays suggest that posterior RA levels are kept low in wild type animals by a likely direct transcriptional regulation of a Cyp26 gene by Cdx. Transcriptome analysis reveals extensive gene expression changes in mutants, with a disproportionate effect of Pdx and Cdx on gut-enriched genes and a colinear-like effect of Cdx on Hox genes. CONCLUSIONS These data reveal that amphioxus Pdx and Cdx have roles in specifying middle and posterior cell fates in the endoderm of the gut, roles that likely date to the origin of Bilateria. This conclusion is consistent with these two ParaHox genes playing a role in the origin of the bilaterian through-gut with a distinct anus, morphological innovations that contributed to ecological change in the Cambrian. In addition, we find that amphioxus Cdx promotes body axis extension through a molecular mechanism conserved with vertebrates. The axial extension role for Cdx dates back at least to the origin of Chordata and may have facilitated the evolution of the post-anal tail and active locomotion in chordates.
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Affiliation(s)
- Yanhong Zhong
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Carlos Herrera-Úbeda
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, UK.,Department of Genetics, Microbiology & Statistics, and Institute of Biomedicine (IBUB), University of Barcelona, 08028, Barcelona, Spain
| | - Jordi Garcia-Fernàndez
- Department of Genetics, Microbiology & Statistics, and Institute of Biomedicine (IBUB), University of Barcelona, 08028, Barcelona, Spain
| | - Guang Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China.
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Andrikou C, Passamaneck YJ, Lowe CJ, Martindale MQ, Hejnol A. Molecular patterning during the development of Phoronopsis harmeri reveals similarities to rhynchonelliform brachiopods. EvoDevo 2019; 10:33. [PMID: 31867094 PMCID: PMC6907167 DOI: 10.1186/s13227-019-0146-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/22/2019] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Phoronids, rhynchonelliform and linguliform brachiopods show striking similarities in their embryonic fate maps, in particular in their axis specification and regionalization. However, although brachiopod development has been studied in detail and demonstrated embryonic patterning as a causal factor of the gastrulation mode (protostomy vs deuterostomy), molecular descriptions are still missing in phoronids. To understand whether phoronids display underlying embryonic molecular mechanisms similar to those of brachiopods, here we report the expression patterns of anterior (otx, gsc, six3/6, nk2.1), posterior (cdx, bra) and endomesodermal (foxA, gata4/5/6, twist) markers during the development of the protostomic phoronid Phoronopsis harmeri. RESULTS The transcription factors foxA, gata4/5/6 and cdx show conserved expression in patterning the development and regionalization of the phoronid embryonic gut, with foxA expressed in the presumptive foregut, gata4/5/6 demarcating the midgut and cdx confined to the hindgut. Furthermore, six3/6, usually a well-conserved anterior marker, shows a remarkably dynamic expression, demarcating not only the apical organ and the oral ectoderm, but also clusters of cells of the developing midgut and the anterior mesoderm, similar to what has been reported for brachiopods, bryozoans and some deuterostome Bilateria. Surprisingly, brachyury, a transcription factor often associated with gastrulation movements and mouth and hindgut development, seems not to be involved with these patterning events in phoronids. CONCLUSIONS Our description and comparison of gene expression patterns with other studied Bilateria reveals that the timing of axis determination and cell fate distribution of the phoronid shows highest similarity to that of rhynchonelliform brachiopods, which is likely related to their shared protostomic mode of development. Despite these similarities, the phoronid Ph. harmeri also shows particularities in its development, which hint to divergences in the arrangement of gene regulatory networks responsible for germ layer formation and axis specification.
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Affiliation(s)
- Carmen Andrikou
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway
| | - Yale J. Passamaneck
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 N Ocean Shore Blvd, St. Augustine, FL, 32080 USA
| | - Chris J. Lowe
- Hopkins Marine Station, Department of Biology, Stanford University, 120 Oceanview Blvd., Pacific Grove, CA 93950 USA
| | - Mark Q. Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 N Ocean Shore Blvd, St. Augustine, FL, 32080 USA
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway
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Powell R, O'Malley MA. Metabolic and microbial perspectives on the "evolution of evolution". JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2019; 332:321-330. [PMID: 31532063 DOI: 10.1002/jez.b.22898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 07/20/2019] [Accepted: 07/23/2019] [Indexed: 06/10/2023]
Abstract
Identifying and theorizing major turning points in the history of life generates insights into not only world-changing evolutionary events but also the processes that bring these events about. In his treatment of these issues, Bonner identifies the evolution of sex, multicellularity, and nervous systems as enabling the "evolution of evolution," which involves fundamental transformations in how evolution occurs. By contextualizing his framework within two decades of theorizing about major transitions in evolution, we identify some basic problems that Bonner's theory shares with much of the prevailing literature. These problems include implicit progressivism, theoretical disunity, and a limited ability to explain major evolutionary transformations. We go on to identify events and processes that are neglected by existing views. In contrast with the "vertical" focus on replication, hierarchy, and morphology that preoccupies most of the literature on major transitions, we propose a "horizontal" dimension in which metabolism and microbial innovations play a central explanatory role in understanding the broad-scale organization of life.
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Affiliation(s)
- Russell Powell
- Department of Philosophy, Boston University, Boston, Massachusetts
| | - Maureen A O'Malley
- School of History and Philosophy of Science, University of Bordeaux/University of Sydney, Sydney, Australia
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Steinmetz PRH. A non-bilaterian perspective on the development and evolution of animal digestive systems. Cell Tissue Res 2019; 377:321-339. [PMID: 31388768 PMCID: PMC6733828 DOI: 10.1007/s00441-019-03075-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/08/2019] [Indexed: 12/14/2022]
Abstract
Digestive systems and extracellular digestion are key animal features, but their emergence during early animal evolution is currently poorly understood. As the last common ancestor of non-bilaterian animal groups (sponges, ctenophores, placozoans and cnidarians) dates back to the beginning of animal life, their study and comparison provides important insights into the early evolution of digestive systems and functions. Here, I have compiled an overview of the development and cell biology of digestive tissues in non-bilaterian animals. I will highlight the fundamental differences between extracellular and intracellular digestive processes, and how these are distributed among animals. Cnidarians (e.g. sea anemones, corals, jellyfish), the phylogenetic outgroup of bilaterians (e.g. vertebrates, flies, annelids), occupy a key position to reconstruct the evolution of bilaterian gut evolution. A major focus will therefore lie on the development and cell biology of digestive tissues in cnidarians, especially sea anemones, and how they compare to bilaterian gut tissues. In that context, I will also review how a recent study on the gastrula fate map of the sea anemone Nematostella vectensis challenges our long-standing conceptions on the evolution of cnidarian and bilaterian germ layers and guts.
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Affiliation(s)
- Patrick R H Steinmetz
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt. 55, 5006, Bergen, Norway.
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Inoue J, Satoh N. ORTHOSCOPE: An Automatic Web Tool for Phylogenetically Inferring Bilaterian Orthogroups with User-Selected Taxa. Mol Biol Evol 2019; 36:621-631. [PMID: 30517749 PMCID: PMC6389317 DOI: 10.1093/molbev/msy226] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Identification of orthologous or paralogous relationships of coding genes is fundamental to all aspects of comparative genomics. For accurate identification of orthologs among deeply diversified bilaterian lineages, precise estimation of gene trees is indispensable, given the complicated histories of genes over millions of years. By estimating gene trees, orthologs can be identified as members of an orthogroup, a set of genes descended from a single gene in the last common ancestor of all the species being considered. In addition to comparisons with a given species tree, purposeful taxonomic sampling increases the accuracy of gene tree estimation and orthogroup identification. Although some major phylogenetic relationships of bilaterians are gradually being unraveled, the scattering of published genomic data among separate web databases is becoming a significant hindrance to identification of orthogroups with appropriate taxonomic sampling. By integrating more than 250 metazoan gene models predicted in genome projects, we developed a web tool called ORTHOSCOPE to identify orthogroups of specific protein-coding genes within major bilaterian lineages. ORTHOSCOPE allows users to employ several sequences of a specific molecule and broadly accepted nodes included in a user-specified species tree as queries and to evaluate the reliability of estimated orthogroups based on topologies and node support values of estimated gene trees. A test analysis using data from 36 bilaterians was accomplished within 140 s. ORTHOSCOPE results can be used to evaluate orthologs identified by other stand-alone programs using genome-scale data. ORTHOSCOPE is freely available at https://www.orthoscope.jp or https://github.com/jun-inoue/orthoscope (last accessed December 28, 2018).
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Affiliation(s)
- Jun Inoue
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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Kostyuchenko RP, Kozin VV, Filippova NA, Sorokina EV. FoxA expression pattern in two polychaete species, Alitta virens and Platynereis dumerilii: Examination of the conserved key regulator of the gut development from cleavage through larval life, postlarval growth, and regeneration. Dev Dyn 2019; 248:728-743. [PMID: 30566266 DOI: 10.1002/dvdy.7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 10/23/2018] [Accepted: 11/29/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND foxA orthologs are involved in various processes from embryo patterning to regulation of metabolism. Since foxA conserved role in the development of the gut of errant annelids has never been thoroughly studied, we used a candidate gene approach to unravel the molecular profile of the alimentary canal in two closely related nereid worms with a trochophore-type lecithotrophic larva. RESULTS The character of foxA expression in the two polychaetes was similar but not identical. The genes were successively activated first in blastoporal cells, then in the stomodeum, the midgut, and hindgut primordia, and in the cells of central and peripheral nervous system. Before the start of active feeding of nectochaetes, we observed a short phase of foxA expression in the entire digestive tract. After amputation of posterior segments, foxA expression was established de novo in the new terminal part of the intestine, and then in the developing hindgut and the anus. CONCLUSIONS We discovered an early marker of endoderm formation previously unknown in errant annelids. Its expression dynamics provided valuable insights into the gut development. Comparative analysis of foxA activity suggests its primary role in gastrulation morphogenesis independently of its type and in midgut and foregut specification. Developmental Dynamics 248:728-743, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Roman P Kostyuchenko
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | - Vitaly V Kozin
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | - Nadezhda A Filippova
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | - Ekaterina V Sorokina
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
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Food Gastrology: A Voyage Through Our Guts. FUTURE FOODS 2019. [DOI: 10.1007/978-3-030-12995-8_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Laumer CE, Gruber-Vodicka H, Hadfield MG, Pearse VB, Riesgo A, Marioni JC, Giribet G. Support for a clade of Placozoa and Cnidaria in genes with minimal compositional bias. eLife 2018; 7:e36278. [PMID: 30373720 PMCID: PMC6277202 DOI: 10.7554/elife.36278] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 10/11/2018] [Indexed: 12/22/2022] Open
Abstract
The phylogenetic placement of the morphologically simple placozoans is crucial to understanding the evolution of complex animal traits. Here, we examine the influence of adding new genomes from placozoans to a large dataset designed to study the deepest splits in the animal phylogeny. Using site-heterogeneous substitution models, we show that it is possible to obtain strong support, in both amino acid and reduced-alphabet matrices, for either a sister-group relationship between Cnidaria and Placozoa, or for Cnidaria and Bilateria as seen in most published work to date, depending on the orthologues selected to construct the matrix. We demonstrate that a majority of genes show evidence of compositional heterogeneity, and that support for the Cnidaria + Bilateria clade can be assigned to this source of systematic error. In interpreting these results, we caution against a peremptory reading of placozoans as secondarily reduced forms of little relevance to broader discussions of early animal evolution.
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Affiliation(s)
- Christopher E Laumer
- Wellcome Trust Sanger InstituteHinxtonUnited Kingdom
- European Molecular Biology Laboratories-European Bioinformatics InstituteHinxtonUnited Kingdom
| | | | - Michael G Hadfield
- Kewalo Marine LaboratoryPacific Biosciences Research Center and the University of Hawaii-ManoaHonoluluUnited States
| | - Vicki B Pearse
- Institute of Marine SciencesUniversity of CaliforniaSanta CruzUnited States
| | - Ana Riesgo
- Invertebrate Division, Life Sciences DepartmentThe Natural History MuseumLondonUnited Kingdom
| | - John C Marioni
- Wellcome Trust Sanger InstituteHinxtonUnited Kingdom
- European Molecular Biology Laboratories-European Bioinformatics InstituteHinxtonUnited Kingdom
- Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUnited Kingdom
| | - Gonzalo Giribet
- Museum of Comparative Zoology, Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeUnited States
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15
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Evolution of the bilaterian mouth and anus. Nat Ecol Evol 2018; 2:1358-1376. [PMID: 30135501 DOI: 10.1038/s41559-018-0641-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 06/26/2018] [Accepted: 07/11/2018] [Indexed: 12/17/2022]
Abstract
It is widely held that the bilaterian tubular gut with mouth and anus evolved from a simple gut with one major gastric opening. However, there is no consensus on how this happened. Did the single gastric opening evolve into a mouth, with the anus forming elsewhere in the body (protostomy), or did it evolve into an anus, with the mouth forming elsewhere (deuterostomy), or did it evolve into both mouth and anus (amphistomy)? These questions are addressed by the comparison of developmental fates of the blastopore, the opening of the embryonic gut, in diverse animals that live today. Here we review comparative data on the identity and fate of blastoporal tissue, investigate how the formation of the through-gut relates to the major body axes, and discuss to what extent evolutionary scenarios are consistent with these data. Available evidence indicates that stem bilaterians had a slit-like gastric opening that was partially closed in subsequent evolution, leaving open the anus and most likely also the mouth, which would favour amphistomy. We discuss remaining difficulties, and outline directions for future research.
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16
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Nakano H, Miyazawa H, Maeno A, Shiroishi T, Kakui K, Koyanagi R, Kanda M, Satoh N, Omori A, Kohtsuka H. A new species of Xenoturbella from the western Pacific Ocean and the evolution of Xenoturbella. BMC Evol Biol 2017; 17:245. [PMID: 29249199 PMCID: PMC5733810 DOI: 10.1186/s12862-017-1080-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/16/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Xenoturbella is a group of marine benthic animals lacking an anus and a centralized nervous system. Molecular phylogenetic analyses group the animal together with the Acoelomorpha, forming the Xenacoelomorpha. This group has been suggested to be either a sister group to the Nephrozoa or a deuterostome, and therefore it may provide important insights into origins of bilaterian traits such as an anus, the nephron, feeding larvae and centralized nervous systems. However, only five Xenoturbella species have been reported and the evolutionary history of xenoturbellids and Xenacoelomorpha remains obscure. RESULTS Here we describe a new Xenoturbella species from the western Pacific Ocean, and report a new xenoturbellid structure - the frontal pore. Non-destructive microCT was used to investigate the internal morphology of this soft-bodied animal. This revealed the presence of a frontal pore that is continuous with the ventral glandular network and which exhibits similarities with the frontal organ in acoelomorphs. CONCLUSIONS Our results suggest that large size, oval mouth, frontal pore and ventral glandular network may be ancestral features for Xenoturbella. Further studies will clarify the evolutionary relationship of the frontal pore and ventral glandular network of xenoturbellids and the acoelomorph frontal organ. One of the habitats of the newly identified species is easily accessible from a marine station and so this species promises to be valuable for research on bilaterian and deuterostome evolution.
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Affiliation(s)
- Hiroaki Nakano
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka, 415-0025, Japan.
| | - Hideyuki Miyazawa
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka, 415-0025, Japan
| | - Akiteru Maeno
- Mammalian Genetics Laboratory, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Toshihiko Shiroishi
- Mammalian Genetics Laboratory, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Keiichi Kakui
- Faculty of Science, Hokkaido University, N10 W8, Kita-ku, Sapporo, Hokkaido, 060-0810, Japan
| | - Ryo Koyanagi
- DNA Sequencing Section, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Miyuki Kanda
- DNA Sequencing Section, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Akihito Omori
- Misaki Marine Biological Station, The University of Tokyo, 1024 Koajiro, Misaki, Miura, Kanagawa, 238-0225, Japan.,Present address: Sado Marine Biological Station, Faculty of Science, Niigata University, Sado, Niigata, 952-2135, Japan
| | - Hisanori Kohtsuka
- Misaki Marine Biological Station, The University of Tokyo, 1024 Koajiro, Misaki, Miura, Kanagawa, 238-0225, Japan
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17
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Lyons DC, Perry KJ, Henry JQ. Morphogenesis along the animal-vegetal axis: fates of primary quartet micromere daughters in the gastropod Crepidula fornicata. BMC Evol Biol 2017; 17:217. [PMID: 28915788 PMCID: PMC5603038 DOI: 10.1186/s12862-017-1057-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 08/29/2017] [Indexed: 11/30/2022] Open
Abstract
Background The Spiralia are a large, morphologically diverse group of protostomes (e.g. molluscs, annelids, nemerteans) that share a homologous mode of early development called spiral cleavage. One of the most highly-conserved features of spiralian development is the contribution of the primary quartet cells, 1a-1d, to the anterior region of the embryo (including the brain, eyes, and the anterior ciliary band, called the prototroch). Yet, very few studies have analyzed the ultimate fates of primary quartet sub-lineages, or examined the morphogenetic events that take place in the anterior region of the embryo. Results This study focuses on the caenogastropod slipper snail, Crepidula fornicata, a model for molluscan developmental biology. Through direct lineage tracing of primary quartet daughter cells, and examination of these cells during gastrulation and organogenesis stages, we uncovered behaviors never described before in a spiralian. For the first time, we show that the 1a2-1d2 cells do not contribute to the prototroch (as they do in other species) and are ultimately lost before hatching. During gastrulation and anterior-posterior axial elongation stages, these cells cleavage-arrest and spread dramatically, contributing to a thin provisional epidermis on the dorsal side of the embryo. This spreading is coupled with the displacement of the animal pole, and other pretrochal cells, closer to the ventrally-positioned mouth, and the vegetal pole. Conclusions This is the first study to document the behavior and fate of primary quartet sub-lineages among molluscs. We speculate that the function of 1a2-1d2 cells (in addition to two cells derived from 1d12, and the 2b lineage) is to serve as a provisional epithelium that allows for anterior displacement of the other progeny of the primary quartet towards the anterior-ventral side of the embryo. These data support a new and novel mechanism for axial bending, distinct from canonical models in which axial bending is suggested to be driven primarily by differential proliferation of posterior dorsal cells. These data suggest also that examining sub-lineages in other spiralians will reveal greater variation than previously assumed.
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Affiliation(s)
- Deirdre C Lyons
- Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, San Diego, CA, 92093, USA.
| | - Kimberly J Perry
- Department of Cell & Developmental Biology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| | - Jonathan Q Henry
- Department of Cell & Developmental Biology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA.
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18
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Steinmetz PRH, Aman A, Kraus JEM, Technau U. Gut-like ectodermal tissue in a sea anemone challenges germ layer homology. Nat Ecol Evol 2017; 1:1535-1542. [PMID: 29185520 DOI: 10.1038/s41559-017-0285-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 07/19/2017] [Indexed: 12/11/2022]
Abstract
Cnidarians (for example, sea anemones and jellyfish) develop from an outer ectodermal and inner endodermal germ layer, whereas bilaterians (for example, vertebrates and flies) additionally have a mesodermal layer as intermediate germ layer. Currently, cnidarian endoderm (that is, 'mesendoderm') is considered homologous to both bilaterian endoderm and mesoderm. Here we test this hypothesis by studying the fate of germ layers, the localization of gut cell types, and the expression of numerous 'endodermal' and 'mesodermal' transcription factor orthologues in the anthozoan sea anemone Nematostella vectensis. Surprisingly, we find that the developing pharyngeal ectoderm and its derivatives display a transcription-factor expression profile (foxA, hhex, islet, soxB1, hlxB9, tbx2/3, nkx6 and nkx2.2) and cell-type combination (exocrine and insulinergic) reminiscent of the developing bilaterian midgut, and, in particular, vertebrate pancreatic tissue. Endodermal derivatives, instead, display cell functions and transcription-factor profiles similar to bilaterian mesoderm derivatives (for example, somatic gonad and heart). Thus, our data supports an alternative model of germ layer homologies, where cnidarian pharyngeal ectoderm corresponds to bilaterian endoderm, and the cnidarian endoderm is homologous to bilaterian mesoderm.
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Affiliation(s)
- Patrick R H Steinmetz
- Department for Molecular Evolution and Development, Centre for Organismal Systems Biology, University of Vienna, Althanstraße 14, A-1090, Vienna, Austria. .,Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5006, Bergen, Norway.
| | - Andy Aman
- Department for Molecular Evolution and Development, Centre for Organismal Systems Biology, University of Vienna, Althanstraße 14, A-1090, Vienna, Austria.,Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA
| | - Johanna E M Kraus
- Department for Molecular Evolution and Development, Centre for Organismal Systems Biology, University of Vienna, Althanstraße 14, A-1090, Vienna, Austria.,Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5006, Bergen, Norway
| | - Ulrich Technau
- Department for Molecular Evolution and Development, Centre for Organismal Systems Biology, University of Vienna, Althanstraße 14, A-1090, Vienna, Austria.
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19
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Janssen R, Budd GE. Investigation of endoderm marker-genes during gastrulation and gut-development in the velvet worm Euperipatoides kanangrensis. Dev Biol 2017; 427:155-164. [DOI: 10.1016/j.ydbio.2017.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 04/14/2017] [Accepted: 04/23/2017] [Indexed: 11/30/2022]
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20
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Vellutini BC, Martín-Durán JM, Hejnol A. Cleavage modification did not alter blastomere fates during bryozoan evolution. BMC Biol 2017; 15:33. [PMID: 28454545 PMCID: PMC5408385 DOI: 10.1186/s12915-017-0371-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 04/04/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Stereotypic cleavage patterns play a crucial role in cell fate determination by precisely positioning early embryonic blastomeres. Although misplaced cell divisions can alter blastomere fates and cause embryonic defects, cleavage patterns have been modified several times during animal evolution. However, it remains unclear how evolutionary changes in cleavage impact the specification of blastomere fates. Here, we analyze the transition from spiral cleavage - a stereotypic pattern remarkably conserved in many protostomes - to a biradial cleavage pattern, which occurred during the evolution of bryozoans. RESULTS Using 3D-live imaging time-lapse microscopy (4D-microscopy), we characterize the cell lineage, MAPK signaling, and the expression of 16 developmental genes in the bryozoan Membranipora membranacea. We found that the molecular identity and the fates of early bryozoan blastomeres are similar to the putative homologous blastomeres in spiral-cleaving embryos. CONCLUSIONS Our work suggests that bryozoans have retained traits of spiral development, such as the early embryonic fate map, despite the evolution of a novel cleavage geometry. These findings provide additional support that stereotypic cleavage patterns can be modified during evolution without major changes to the molecular identity and fate of embryonic blastomeres.
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Affiliation(s)
- Bruno C Vellutini
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway
| | - José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway.
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21
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Han J, Morris SC, Ou Q, Shu D, Huang H. Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China). Nature 2017; 542:228-231. [PMID: 28135722 DOI: 10.1038/nature21072] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 12/22/2016] [Indexed: 02/01/2023]
Abstract
Deuterostomes include the group we belong to (vertebrates) as well as an array of disparate forms that include echinoderms, hemichordates and more problematic groups such as vetulicolians and vetulocystids. The Cambrian fossil record is well-populated with representative examples, but possible intermediates are controversial and the nature of the original deuterostome remains idealized. Here we report millimetric fossils, Saccorhytus coronarius nov. gen., nov. sp., from an Orsten-like Lagerstätte from the earliest Cambrian period of South China, which stratigraphically are amongst the earliest of deuterostomes. The bag-like body bears a prominent mouth and associated folds, and behind them up to four conical openings on either side of the body as well as possible sensory structures. An anus may have been absent, and correspondingly the lateral openings probably served to expel water and waste material. This new form has similarities to both the vetulicolians and vetulocystids and collectively these findings suggest that a key step in deuterostome evolution was the development of lateral openings that subsequently were co-opted as pharyngeal gills. Depending on its exact phylogenetic position, the meiofaunal habit of Saccorhytus may help to explain the major gap between divergence times seen in the fossil record and estimates based on molecular clocks.
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Affiliation(s)
- Jian Han
- State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China
| | - Simon Conway Morris
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
| | - Qiang Ou
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China.,Department of Zoology, University of Kassel, Kassel 34132, Germany
| | - Degan Shu
- State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China
| | - Hai Huang
- College of Petroleum Engineering, Xi'an Shiyou University, Xi'an 710065, China
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22
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Sebé-Pedrós A, Ruiz-Trillo I. Evolution and Classification of the T-Box Transcription Factor Family. Curr Top Dev Biol 2017; 122:1-26. [DOI: 10.1016/bs.ctdb.2016.06.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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23
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Thiruketheeswaran P, Greven H, D'Haese J. Gelsolin in Onychophora and Tardigrada with notes on its variability in the Ecdysozoa. Comp Biochem Physiol B Biochem Mol Biol 2016; 203:47-52. [PMID: 27627778 DOI: 10.1016/j.cbpb.2016.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/31/2016] [Accepted: 09/08/2016] [Indexed: 01/25/2023]
Abstract
Rearrangements of the filamentous actin network involve a broad range of actin binding proteins. Among these, the gelsolin proteins sever actin filaments, cap their fast growing end and nucleate actin assembly in a calcium-dependent manner. Here, we focus on the gelsolin of the onychophoran Peripatoides novaezealandiae and the eutardigrade Hypsibius dujardini. From the cDNA of P. novaezealandiae we obtained the complete coding sequence with an open reading frame of 2178bp. It encodes a protein of 726 amino acids with a calculated molecular mass of 82,610.9Da and a pI of 5.57. This sequence is comprised of six segments (S1-S6). However, analysis of data from TardiBase reveals that the gelsolin of the eutardigrade Hypsibius dujardini has only three segments (S1-S3). The coding sequence consist of 1119bp for 373 amino acids with a calculated molecular mass of 42,440.95Da and a pI of 6.17. The Peripatoides and Hypsibius gelsolin revealed both conserved binding motifs for G-actin, F-actin and phosphatidylinositol 4,5-bisphosphate (PIP2), along with a full set of type-1 and type-2 Ca2+-binding sites which could result in the binding of eight and four calcium ions, respectively. Both gelsolin proteins lack a C-terminal latch-helix indicating a more rapid activation in the submicromolar Ca2+ range. We suggest that a gelsolin with three segments was present in the last common ancestor of the ecdysozoan clade Panarthropoda (Onychophora, Tardigrada, Arthropoda), primarily because the gelsolin of all non-Ecdysozoa studied so far (except Chordata) reveals this number of segments. Mapping of our molecular data onto a well-established phylogeny revealed that the number of gelsolin segments does not correlate with the phylogenetic lineage but rather with particular functional demands to alter the kinetics of actin polymerization.
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Affiliation(s)
- Prasath Thiruketheeswaran
- Institute for Cell Biology, Department Biology, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Hartmut Greven
- Institute for Cell Biology, Department Biology, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Jochen D'Haese
- Institute for Cell Biology, Department Biology, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany.
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24
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The Presence of a Functionally Tripartite Through-Gut in Ctenophora Has Implications for Metazoan Character Trait Evolution. Curr Biol 2016; 26:2814-2820. [DOI: 10.1016/j.cub.2016.08.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 08/03/2016] [Accepted: 08/04/2016] [Indexed: 01/04/2023]
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25
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Budd GE, Jackson ISC. Ecological innovations in the Cambrian and the origins of the crown group phyla. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150287. [PMID: 26598735 PMCID: PMC4685591 DOI: 10.1098/rstb.2015.0287] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Simulation studies of the early origins of the modern phyla in the fossil record, and the rapid diversification that led to them, show that these are inevitable outcomes of rapid and long-lasting radiations. Recent advances in Cambrian stratigraphy have revealed a more precise picture of the early bilaterian radiation taking place during the earliest Terreneuvian Series, although several ambiguities remain. The early period is dominated by various tubes and a moderately diverse trace fossil record, with the classical ‘Tommotian’ small shelly biota beginning to appear some millions of years after the base of the Cambrian at ca 541 Ma. The body fossil record of the earliest period contains a few representatives of known groups, but most of the record is of uncertain affinity. Early trace fossils can be assigned to ecdysozoans, but deuterostome and even spiralian trace and body fossils are less clearly represented. One way of explaining the relative lack of clear spiralian fossils until about 536 Ma is to assign the various lowest Cambrian tubes to various stem-group lophotrochozoans, with the implication that the groundplan of the lophotrochozoans included a U-shaped gut and a sessile habit. The implication of this view would be that the vagrant lifestyle of annelids, nemerteans and molluscs would be independently derived from such a sessile ancestor, with potentially important implications for the homology of their sensory and nervous systems.
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Affiliation(s)
- Graham E Budd
- Department of Earth Sciences, Palaeobiology Programme, Uppsala University, Villavägen 16, Uppsala 752 36, Sweden
| | - Illiam S C Jackson
- Department of Earth Sciences, Palaeobiology Programme, Uppsala University, Villavägen 16, Uppsala 752 36, Sweden
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26
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Perry KJ, Lyons DC, Truchado-Garcia M, Fischer AHL, Helfrich LW, Johansson KB, Diamond JC, Grande C, Henry JQ. Deployment of regulatory genes during gastrulation and germ layer specification in a model spiralian mollusc Crepidula. Dev Dyn 2016. [PMID: 26197970 DOI: 10.1002/dvdy.24308] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND During gastrulation, endoderm and mesoderm are specified from a bipotential precursor (endomesoderm) that is argued to be homologous across bilaterians. Spiralians also generate mesoderm from ectodermal precursors (ectomesoderm), which arises near the blastopore. While a conserved gene regulatory network controls specification of endomesoderm in deuterostomes and ecdysozoans, little is known about genes controlling specification or behavior of either source of spiralian mesoderm or the digestive tract. RESULTS Using the mollusc Crepidula, we examined conserved regulatory factors and compared their expression to fate maps to score expression in the germ layers, blastopore lip, and digestive tract. Many genes were expressed in both ecto- and endomesoderm, but only five were expressed in ectomesoderm exclusively. The latter may contribute to epithelial-to-mesenchymal transition seen in ectomesoderm. CONCLUSIONS We present the first comparison of genes expressed during spiralian gastrulation in the context of high-resolution fate maps. We found variation of genes expressed in the blastopore lip, mouth, and cells that will form the anus. Shared expression of many genes in both mesodermal sources suggests that components of the conserved endomesoderm program were either co-opted for ectomesoderm formation or that ecto- and endomesoderm are derived from a common mesodermal precursor that became subdivided into distinct domains during evolution.
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Affiliation(s)
- Kimberly J Perry
- University of Illinois, Department of Cell and Developmental Biology, Urbana, Illinois
| | | | - Marta Truchado-Garcia
- Departamento de Biología Molecular and Centro de Biología Molecular, "Severo Ochoa" (CSIC, Universidad Autónoma de Madrid), Madrid, Spain
| | - Antje H L Fischer
- Department of Metabolic Biochemistry, Ludwig-Maximilians-University, Munich, Germany.,Marine Biological Laboratory, Woods Hole, Massachusetts
| | | | - Kimberly B Johansson
- Marine Biological Laboratory, Woods Hole, Massachusetts.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts
| | | | - Cristina Grande
- Departamento de Biología Molecular and Centro de Biología Molecular, "Severo Ochoa" (CSIC, Universidad Autónoma de Madrid), Madrid, Spain
| | - Jonathan Q Henry
- University of Illinois, Department of Cell and Developmental Biology, Urbana, Illinois
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27
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Hejnol A, Pang K. Xenacoelomorpha's significance for understanding bilaterian evolution. Curr Opin Genet Dev 2016; 39:48-54. [PMID: 27322587 DOI: 10.1016/j.gde.2016.05.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 04/02/2016] [Accepted: 05/30/2016] [Indexed: 12/25/2022]
Abstract
The Xenacoelomorpha, with its phylogenetic position as sister group of the Nephrozoa (Protostomia+Deuterostomia), plays a key-role in understanding the evolution of bilaterian cell types and organ systems. Current studies of the morphological and developmental diversity of this group allow us to trace the evolution of different organ systems within the group and to reconstruct characters of the most recent common ancestor of Xenacoelomorpha. The disparity of the clade shows that there cannot be a single xenacoelomorph 'model' species and strategic sampling is essential for understanding the evolution of major traits. With this strategy, fundamental insights into the evolution of molecular mechanisms and their role in shaping animal organ systems can be expected in the near future.
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Affiliation(s)
- Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway.
| | - Kevin Pang
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
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28
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29
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Hejnol A, Lowe CJ. Embracing the comparative approach: how robust phylogenies and broader developmental sampling impacts the understanding of nervous system evolution. Philos Trans R Soc Lond B Biol Sci 2015; 370:20150045. [PMID: 26554039 PMCID: PMC4650123 DOI: 10.1098/rstb.2015.0045] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2015] [Indexed: 12/14/2022] Open
Abstract
Molecular biology has provided a rich dataset to develop hypotheses of nervous system evolution. The startling patterning similarities between distantly related animals during the development of their central nervous system (CNS) have resulted in the hypothesis that a CNS with a single centralized medullary cord and a partitioned brain is homologous across bilaterians. However, the ability to precisely reconstruct ancestral neural architectures from molecular genetic information requires that these gene networks specifically map with particular neural anatomies. A growing body of literature representing the development of a wider range of metazoan neural architectures demonstrates that patterning gene network complexity is maintained in animals with more modest levels of neural complexity. Furthermore, a robust phylogenetic framework that provides the basis for testing the congruence of these homology hypotheses has been lacking since the advent of the field of 'evo-devo'. Recent progress in molecular phylogenetics is refining the necessary framework to test previous homology statements that span large evolutionary distances. In this review, we describe recent advances in animal phylogeny and exemplify for two neural characters-the partitioned brain of arthropods and the ventral centralized nerve cords of annelids-a test for congruence using this framework. The sequential sister taxa at the base of Ecdysozoa and Spiralia comprise small, interstitial groups. This topology is not consistent with the hypothesis of homology of tripartitioned brain of arthropods and vertebrates as well as the ventral arthropod and rope-like ladder nervous system of annelids. There can be exquisite conservation of gene regulatory networks between distantly related groups with contrasting levels of nervous system centralization and complexity. Consequently, the utility of molecular characters to reconstruct ancestral neural organization in deep time is limited.
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Affiliation(s)
- Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, Bergen 5008, Norway
| | - Christopher J Lowe
- Hopkins Marine Station, Department of Biology, Stanford University, 120 Oceanview Blvd., Pacific Grove, CA 93950, USA
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Haszprunar G. Review of data for a morphological look on Xenacoelomorpha (Bilateria incertae sedis). ORG DIVERS EVOL 2015. [DOI: 10.1007/s13127-015-0249-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Affiliation(s)
- Martijn Pieter Gosselink
- Department of Colorectal Surgery, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
| | | | - W R Schouten
- Department of Colorectal Surgery, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
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Lyons DC, Perry KJ, Henry JQ. Spiralian gastrulation: germ layer formation, morphogenesis, and fate of the blastopore in the slipper snail Crepidula fornicata. EvoDevo 2015; 6:24. [PMID: 26664718 PMCID: PMC4673862 DOI: 10.1186/s13227-015-0019-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 04/15/2015] [Indexed: 12/14/2022] Open
Abstract
Background Gastrulation is a critical step in bilaterian development, directly linked to the segregation of germ layers, establishment of axes, and emergence of the through-gut. Theories about the evolution of gastrulation often concern the fate of the blastopore (site of endomesoderm internalization), which varies widely in a major branch of bilaterians, the Spiralia. In this group, the blastopore has been said to become the mouth, the anus, both, or neither. Different developmental explanations for this variation exist, yet no modern lineage tracing study has ever correlated the position of cells surrounding the blastopore with their contribution to tissues of the mouth, foregut, and anus in a spiralian. This is the first study to do so, using the gastropod Crepidula fornicata. Results Crepidula gastrulation occurs by epiboly: the first through third quartet micromeres form an epithelial animal cap that expands to cover vegetal endomesodermal precursors. Initially, descendants of the second and third quartet micromeres (2a–2d, 3a–3d) occupy a portion of the blastopore lip. As the blastopore narrows, the micromeres’ progeny exhibit lineage-specific behaviors that result in certain sublineages leaving the lip’s edge. Anteriorly, cells derived from 3a2 and 3b2 undergo a unique epithelial-to-mesenchymal transition involving proliferation and a collective movement of cells into the archenteron. These cells make a novel spiralian germ layer, the ectomesoderm. Posteriorly, cells derived from 3c2 and 3d2 undergo a form of convergence and extension that involves zippering of cells and their intercalation across the ventral midline. During this process, several of these cells, as well as the 2d clone, become displaced posteriorly, away from the blastopore. Progeny of 2a-2c and 3a-3d make the mouth and foregut, and the blastopore becomes the opening to the mouth. The anus forms days later, as a secondary opening within the 2d2 clone, and not from the classically described “anal cells”, which we identify as the 3c221 and 3d221 cells. Conclusions Our analysis of Crepidula gastrulation constitutes the first description of blastopore lip morphogenesis and fates using lineage tracing and live imaging. These data have profound implications for hypotheses about the evolution of the bilaterian gut and help explain observed variation in blastopore morphogenesis among spiralians. Electronic supplementary material The online version of this article (doi:10.1186/s13227-015-0019-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Deirdre C Lyons
- Biology Department, Duke University, 124 Science Drive, Durham, NC 27708 USA
| | - Kimberly J Perry
- Department of Cell and Developmental Biology, University of Illinois, 601 S. Goodwin Ave., Urbana, IL 61801 USA
| | - Jonathan Q Henry
- Department of Cell and Developmental Biology, University of Illinois, 601 S. Goodwin Ave., Urbana, IL 61801 USA
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Martín-Durán JM, Hejnol A. The study of Priapulus caudatus reveals conserved molecular patterning underlying different gut morphogenesis in the Ecdysozoa. BMC Biol 2015; 13:29. [PMID: 25895830 PMCID: PMC4434581 DOI: 10.1186/s12915-015-0139-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 04/13/2015] [Indexed: 12/14/2022] Open
Abstract
Background The digestive systems of animals can become highly specialized in response to their exploration and occupation of new ecological niches. Although studies on different animals have revealed commonalities in gut formation, the model systems Caenorhabditis elegans and Drosophila melanogaster, which belong to the invertebrate group Ecdysozoa, exhibit remarkable deviations in how their intestines develop. Their morphological and developmental idiosyncrasies have hindered reconstructions of ancestral gut characters for the Ecdysozoa, and limit comparisons with vertebrate models. In this respect, the phylogenetic position, and slow evolving morphological and molecular characters of marine priapulid worms advance them as a key group to decipher evolutionary events that occurred in the lineages leading to C. elegans and D. melanogaster. Results In the priapulid Priapulus caudatus, the gut consists of an ectodermal foregut and anus, and a mid region of at least partial endodermal origin. The inner gut develops into a 16-cell primordium devoid of visceral musculature, arranged in three mid tetrads and two posterior duplets. The mouth invaginates ventrally and shifts to a terminal anterior position as the ventral anterior ectoderm differentially proliferates. Contraction of the musculature occurs as the head region retracts into the trunk and resolves the definitive larval body plan. Despite obvious developmental differences with C. elegans and D. melanogaster, the expression in P. caudatus of the gut-related candidate genes NK2.1, foxQ2, FGF8/17/18, GATA456, HNF4, wnt1, and evx demonstrate three distinct evolutionarily conserved molecular profiles that correlate with morphologically identified sub-regions of the gut. Conclusions The comparative analysis of priapulid development suggests that a midgut formed by a single endodermal population of vegetal cells, a ventral mouth, and the blastoporal origin of the anus are ancestral features in the Ecdysozoa. Our molecular data on P. caudatus reveal a conserved ecdysozoan gut-patterning program and demonstrates that extreme morphological divergence has not been accompanied by major molecular innovations in transcriptional regulators during digestive system evolution in the Ecdysozoa. Our data help us understand the origins of the ecdysozoan body plan, including those of C. elegans and D. melanogaster, and this is critical for comparisons between these two prominent model systems and their vertebrate counterparts. Electronic supplementary material The online version of this article (doi:10.1186/s12915-015-0139-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008, Bergen, Norway.
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008, Bergen, Norway.
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