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Parey E, Berthelot C, Roest Crollius H, Guiguen Y. Solving an enigma in the tree of life, at the origins of teleost fishes. C R Biol 2024; 347:1-8. [PMID: 38441104 DOI: 10.5802/crbiol.150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/05/2024] [Accepted: 02/09/2024] [Indexed: 03/07/2024]
Abstract
Tracing the phylogenetic relationships between species is one of the fundamental objectives of evolutionary biology. Since Charles Darwin's seminal work in the 19th century, considerable progress has been made towards establishing a tree of life that summarises the evolutionary history of species. Nevertheless, substantial uncertainties still remain. Specifically, the relationships at the origins of teleost fishes have been the subject of extensive debate over the last 50 years. This question has major implications for various research fields: there are almost 30,000 species in the teleost group, which includes invaluable model organisms for biomedical, evolutionary and ecological studies. Here, we present the work in which we solved this enigma. We demonstrated that eels are more closely related to bony-tongued fishes than to the rest of teleost fishes. We achieved this by taking advantage of new genomic data and leveraging innovative phylogenetic markers. Notably, in addition to traditional molecular phylogeny methods based on the evolution of gene sequences, we also considered the evolution of gene order along the DNA molecule. We discuss the challenges and opportunities that these new markers represent for the field of molecular phylogeny, and in particular the possibilities they offer for re-examining other controversial branches in the tree of life.
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2
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Herringe CA, Middleton EJ, Boyd KC, Latty T, White TE. Benefits and costs of social foraging in velvet worms. Ethology 2021. [DOI: 10.1111/eth.13256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Caragh A. Herringe
- School of Life and Environmental Sciences The University of Sydney Sydney Australia
| | - Eliza J. Middleton
- School of Life and Environmental Sciences The University of Sydney Sydney Australia
| | - Kelsey C. Boyd
- School of Life and Environmental Sciences The University of Sydney Sydney Australia
- School of Earth, Atmospheric and Life Sciences University of Wollongong Wollongong Australia
| | - Tanya Latty
- School of Life and Environmental Sciences The University of Sydney Sydney Australia
| | - Thomas E. White
- School of Life and Environmental Sciences The University of Sydney Sydney Australia
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3
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Wei R, Yang J, He LJ, Liu HM, Hu JY, Liang SQ, Wei XP, Zhao CF, Zhang XC. Plastid phylogenomics provides novel insights into the infrafamilial relationship of Polypodiaceae. Cladistics 2021; 37:717-727. [PMID: 34841589 DOI: 10.1111/cla.12461] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2021] [Indexed: 01/01/2023] Open
Abstract
The polygrammoids (Polypodiaceae) are the most species-rich and diversified epiphytic fern lineages, and hold an important role to understand the deep diverging events and rapid adaptation to changing environments in the plant tree of life. Despite progress in the phylogeny of this group of ferns in previous multilocus phylogenetic studies, uncertainty remains especially in backbone relationships among closely related clades, and the phylogenetic placement of recalcitrant species or lineages. Here, we investigated the deep phylogenetic relationships within Polypodiaceae by sampling all major lineages and using 81 plastid genomes (plastomes), of which 70 plastomes were newly sequenced with high-throughput sequencing technology. Based on parsimony, maximum-likelihood, Bayesian and multispecies coalescent analyses of genome skimming data, we achieved a better resolution of the backbone phylogeny of Polypodiaceae. Using simulated data matrices, we detected that potential phylogenetic artefacts, such as long-branch attraction and insufficient taxonomic sampling, may have a confounding impact on the incongruence of phylogenetic inferences. Furthermore, our phylogenetic analyses offer greater resolution than previous multilocus studies, providing a robust framework for future phylogenetic implications on the subfamilial taxonomy of Polypodiaceae. Our phylogenomic study not only demonstrates the advantage of a character-rich plastome dataset for resolving the recalcitrant lineages that have undergone rapid radiation, but also sheds new light on integrative explorations understanding the evolutionary history of large fern groups in the genomic era.
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Affiliation(s)
- Ran Wei
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Jie Yang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Li-Juan He
- Xiamen Overseas Chinese Subtropical Plant Introduction Garden/Plant Introduction & Quarantine and Plant Product Key Laboratory of Xiamen, Xiamen, Fujian, 361002, China
| | - Hong-Mei Liu
- Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunnan, 666303, China
| | - Jia-Yu Hu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Si-Qi Liang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xue-Ping Wei
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100193, China
| | - Cun-Feng Zhao
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xian-Chun Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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4
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F. A. Abdelhameed R, Habib ES, Eltahawy NA, Hassanean HA, Ibrahim AK, Fahim JR, Sayed AM, Hendawy OM, Abdelmohsen UR, Ahmed SA. New glucose-6-phosphate dehydrogenase inhibitor from the Red Sea sponge Echinoclathria sp. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.152986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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5
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Arribas P, Andújar C, Moraza ML, Linard B, Emerson BC, Vogler AP. Mitochondrial Metagenomics Reveals the Ancient Origin and Phylodiversity of Soil Mites and Provides a Phylogeny of the Acari. Mol Biol Evol 2020; 37:683-694. [PMID: 31670799 DOI: 10.1093/molbev/msz255] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
High-throughput DNA methods hold great promise for phylogenetic analysis of lineages that are difficult to study with conventional molecular and morphological approaches. The mites (Acari), and in particular the highly diverse soil-dwelling lineages, are among the least known branches of the metazoan Tree-of-Life. We extracted numerous minute mites from soils in an area of mixed forest and grassland in southern Iberia. Selected specimens representing the full morphological diversity were shotgun sequenced in bulk, followed by genome assembly of short reads from the mixture, which produced >100 mitochondrial genomes representing diverse acarine lineages. Phylogenetic analyses in combination with taxonomically limited mitogenomes available publicly resulted in plausible trees defining basal relationships of the Acari. Several critical nodes were supported by ancestral-state reconstructions of mitochondrial gene rearrangements. Molecular calibration placed the minimum age for the common ancestor of the superorder Acariformes, which includes most soil-dwelling mites, to the Cambrian-Ordovician (likely within 455-552 Ma), whereas the origin of the superorder Parasitiformes was placed later in the Carboniferous-Permian. Most family-level taxa within the Acariformes were dated to the Jurassic and Triassic. The ancient origin of Acariformes and the early diversification of major extant lineages linked to the soil are consistent with a pioneering role for mites in building the earliest terrestrial ecosystems.
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Affiliation(s)
- Paula Arribas
- Island Ecology and Evolution Research Group, IPNA-CSIC, La Laguna, Tenerife, Spain.,Department of Life Sciences, Natural History Museum, London, United Kingdom.,Department of Life Sciences, Imperial College London, Ascot, United Kingdom
| | - Carmelo Andújar
- Island Ecology and Evolution Research Group, IPNA-CSIC, La Laguna, Tenerife, Spain.,Department of Life Sciences, Natural History Museum, London, United Kingdom.,Department of Life Sciences, Imperial College London, Ascot, United Kingdom
| | - María Lourdes Moraza
- Departamento de Biología Ambiental, Universidad de Navarra, Facultad de Ciencias, Pamplona, Spain
| | - Benjamin Linard
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,LIRMM, Université de Montpellier, CNRS, Montpellier, France.,ISEM, Université de Montpellier, CNRS, IRD, EPHE, CIRAD, INRAP, Montpellier, France
| | - Brent C Emerson
- Island Ecology and Evolution Research Group, IPNA-CSIC, La Laguna, Tenerife, Spain
| | - Alfried P Vogler
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,Department of Life Sciences, Imperial College London, Ascot, United Kingdom
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6
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Martín-Durán JM, Hejnol A. A developmental perspective on the evolution of the nervous system. Dev Biol 2019; 475:181-192. [PMID: 31610146 DOI: 10.1016/j.ydbio.2019.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 06/02/2018] [Accepted: 10/04/2019] [Indexed: 12/20/2022]
Abstract
The evolution of nervous systems in animals has always fascinated biologists, and thus multiple evolutionary scenarios have been proposed to explain the appearance of neurons and complex neuronal centers. However, the absence of a robust phylogenetic framework for animal interrelationships, the lack of a mechanistic understanding of development, and a recapitulative view of animal ontogeny have traditionally limited these scenarios. Only recently, the integration of advanced molecular and morphological studies in a broad range of animals has allowed to trace the evolution of developmental and neuronal characters on a better-resolved animal phylogeny. This has falsified most traditional scenarios for nervous system evolution, paving the way for the emergence of new testable hypotheses. Here we summarize recent progress in studies of nervous system development in major animal lineages and formulate some of the arising questions. In particular, we focus on how lineage analyses of nervous system development and a comparative study of the expression of neural-related genes has influenced our understanding of the evolution of an elaborated central nervous system in Bilateria. We argue that a phylogeny-guided study of neural development combining thorough descriptive and functional analyses is key to establish more robust scenarios for the origin and evolution of animal nervous systems.
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Affiliation(s)
- José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thørmohlensgate 55, 5006, Bergen, Norway; School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, E1 4NS, London, UK.
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thørmohlensgate 55, 5006, Bergen, Norway.
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7
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Yu Y, Yang J, Ma W, Pressel S, Liu H, Wu Y, Schneider H. Chloroplast phylogenomics of liverworts: a reappraisal of the backbone phylogeny of liverworts with emphasis on Ptilidiales. Cladistics 2019; 36:184-193. [DOI: 10.1111/cla.12396] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2019] [Indexed: 01/20/2023] Open
Affiliation(s)
- Ying Yu
- College of Life and Environmental Sciences Hangzhou Normal University Hangzhou 311121 China
| | - Jun‐Bo Yang
- CAS Plant Germplasm and Genomics Center Germplasm Bank of Wild Species Kunming Institute of Botany Chinese Academy of Sciences Kunming 650201 China
| | - Wen‐Zhang Ma
- CAS Key Laboratory for Plant Biodiversity and Biogeography of East Asia Kunming Institute of Botany Chinese Academy of Sciences Kunming 650201 China
| | - Silvia Pressel
- Department of Life Sciences Natural History Museum London SW7 5BD UK
| | - Hong‐Mei Liu
- Key Laboratory of Tropical Plant Resources and Sustainable Use Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Menglun Yunnan 666303 China
| | - Yu‐Huan Wu
- College of Life and Environmental Sciences Hangzhou Normal University Hangzhou 311121 China
| | - Harald Schneider
- Center of Integrative Conservation Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Menglun Yunnan 666303 China
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8
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Laumer CE, Fernández R, Lemer S, Combosch D, Kocot KM, Riesgo A, Andrade SCS, Sterrer W, Sørensen MV, Giribet G. Revisiting metazoan phylogeny with genomic sampling of all phyla. Proc Biol Sci 2019; 286:20190831. [PMID: 31288696 PMCID: PMC6650721 DOI: 10.1098/rspb.2019.0831] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 06/17/2019] [Indexed: 11/21/2022] Open
Abstract
Proper biological interpretation of a phylogeny can sometimes hinge on the placement of key taxa-or fail when such key taxa are not sampled. In this light, we here present the first attempt to investigate (though not conclusively resolve) animal relationships using genome-scale data from all phyla. Results from the site-heterogeneous CAT + GTR model recapitulate many established major clades, and strongly confirm some recent discoveries, such as a monophyletic Lophophorata, and a sister group relationship between Gnathifera and Chaetognatha, raising continued questions on the nature of the spiralian ancestor. We also explore matrix construction with an eye towards testing specific relationships; this approach uniquely recovers support for Panarthropoda, and shows that Lophotrochozoa (a subclade of Spiralia) can be constructed in strongly conflicting ways using different taxon- and/or orthologue sets. Dayhoff-6 recoding sacrifices information, but can also reveal surprising outcomes, e.g. full support for a clade of Lophophorata and Entoprocta + Cycliophora, a clade of Placozoa + Cnidaria, and raising support for Ctenophora as sister group to the remaining Metazoa, in a manner dependent on the gene and/or taxon sampling of the matrix in question. Future work should test the hypothesis that the few remaining uncertainties in animal phylogeny might reflect violations of the various stationarity assumptions used in contemporary inference methods.
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Affiliation(s)
- Christopher E. Laumer
- Museum of Comparative Zoology (MCZ) and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
- EMBL-European Bioinformatics Institute (EBI), Wellcome Genome Campus, Hinxton CB10 1SD, UK
| | - Rosa Fernández
- Museum of Comparative Zoology (MCZ) and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
- Bioinformatics & Genomics Unit, Center for Genomic Regulation, Carrer del Dr. Aiguader 88, 08003 Barcelona (Spain)
| | - Sarah Lemer
- Museum of Comparative Zoology (MCZ) and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
- Marine Laboratory, University of Guam, UOG Station, Mangilao, Guam 96923, USA
| | - David Combosch
- Museum of Comparative Zoology (MCZ) and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
- Marine Laboratory, University of Guam, UOG Station, Mangilao, Guam 96923, USA
| | - Kevin M. Kocot
- Department of Biological Sciences and Alabama Museum of Natural History, The University of Alabama, Campus Box 870344, Tuscaoosa, AL 35487, USA
| | - Ana Riesgo
- Department of Life Sciences, Natural History Museum of London, Cromwell Road, London SW7 5BD, UK
| | - Sónia C. S. Andrade
- Departamento de Genética e Biologia Evolutiva, IB, Universidade de São Paulo, 05508090 São Paulo, SP, Brazil
| | - Wolfgang Sterrer
- Bermuda Natural History Museum, PO Box FL 145, Flatts, FLBX, Bermuda
| | - Martin V. Sørensen
- Natural History Museum of Denmark, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Gonzalo Giribet
- Museum of Comparative Zoology (MCZ) and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
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9
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Guil N, Jørgensen A, Kristensen R. An upgraded comprehensive multilocus phylogeny of the Tardigrada tree of life. ZOOL SCR 2018. [DOI: 10.1111/zsc.12321] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Noemi Guil
- Department of Biodiversity and Evolutionary Biology Museo Nacional de Ciencias Naturales (MNCN‐CSIC) Madrid Spain
| | - Aslak Jørgensen
- Department of Biology University of Copenhagen Copenhagen Denmark
| | - Reinhardt Kristensen
- Zoological Museum, Natural History Museum of Denmark University of Copenhagen Copenhagen Denmark
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10
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Haag ES, Fitch DHA, Delattre M. From "the Worm" to "the Worms" and Back Again: The Evolutionary Developmental Biology of Nematodes. Genetics 2018; 210:397-433. [PMID: 30287515 PMCID: PMC6216592 DOI: 10.1534/genetics.118.300243] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 08/03/2018] [Indexed: 12/13/2022] Open
Abstract
Since the earliest days of research on nematodes, scientists have noted the developmental and morphological variation that exists within and between species. As various cellular and developmental processes were revealed through intense focus on Caenorhabditis elegans, these comparative studies have expanded. Within the genus Caenorhabditis, they include characterization of intraspecific polymorphisms and comparisons of distinct species, all generally amenable to the same laboratory culture methods and supported by robust genomic and experimental tools. The C. elegans paradigm has also motivated studies with more distantly related nematodes and animals. Combined with improved phylogenies, this work has led to important insights about the evolution of nematode development. First, while many aspects of C. elegans development are representative of Caenorhabditis, and of terrestrial nematodes more generally, others vary in ways both obvious and cryptic. Second, the system has revealed several clear examples of developmental flexibility in achieving a particular trait. This includes developmental system drift, in which the developmental control of homologous traits has diverged in different lineages, and cases of convergent evolution. Overall, the wealth of information and experimental techniques developed in C. elegans is being leveraged to make nematodes a powerful system for evolutionary cellular and developmental biology.
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Affiliation(s)
- Eric S Haag
- Department of Biology, University of Maryland, College Park, Maryland 20742
| | | | - Marie Delattre
- Laboratoire de Biologie Moléculaire de la Cellule, CNRS, INSERM, Ecole Normale Supérieure de Lyon, 69007, France
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11
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Thiel D, Franz-Wachtel M, Aguilera F, Hejnol A. Xenacoelomorph Neuropeptidomes Reveal a Major Expansion of Neuropeptide Systems during Early Bilaterian Evolution. Mol Biol Evol 2018. [PMCID: PMC6188537 DOI: 10.1093/molbev/msy160] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuropeptides are neurosecretory signaling molecules in protostomes and deuterostomes (together Nephrozoa). Little, however, is known about the neuropeptide complement of the sister group of Nephrozoa, the Xenacoelomorpha, which together form the Bilateria. Because members of the xenacoelomorph clades Xenoturbella, Nemertodermatida, and Acoela differ extensively in their central nervous system anatomy, the reconstruction of the xenacoelomorph and bilaterian neuropeptide complements may provide insights into the relationship between nervous system evolution and peptidergic signaling. Here, we analyzed transcriptomes of seven acoels, four nemertodermatids, and two Xenoturbella species using motif searches, similarity searches, mass spectrometry and phylogenetic analyses to characterize neuropeptide precursors and neuropeptide receptors. Our comparison of these repertoires with previously reported nephrozoan and cnidarian sequences shows that the majority of annotated neuropeptide GPCRs in cnidarians are not orthologs of specific bilaterian neuropeptide receptors, which suggests that most of the bilaterian neuropeptide systems evolved after the cnidarian–bilaterian evolutionary split. This expansion of more than 20 peptidergic systems in the stem leading to the Bilateria predates the evolution of complex nephrozoan organs and nervous system architectures. From this ancient set of neuropeptides, acoels show frequent losses that correlate with their divergent central nervous system anatomy. We furthermore detected the emergence of novel neuropeptides in xenacoelomorphs and their expansion along the nemertodermatid and acoel lineages, the two clades that evolved nervous system condensations. Together, our study provides fundamental insights into the early evolution of the bilaterian peptidergic systems, which will guide future functional and comparative studies of bilaterian nervous systems.
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Affiliation(s)
- Daniel Thiel
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | | | - Felipe Aguilera
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
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12
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Smith FW, Cumming M, Goldstein B. Analyses of nervous system patterning genes in the tardigrade Hypsibius exemplaris illuminate the evolution of panarthropod brains. EvoDevo 2018; 9:19. [PMID: 30069303 PMCID: PMC6065069 DOI: 10.1186/s13227-018-0106-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/16/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Both euarthropods and vertebrates have tripartite brains. Several orthologous genes are expressed in similar regionalized patterns during brain development in both vertebrates and euarthropods. These similarities have been used to support direct homology of the tripartite brains of vertebrates and euarthropods. If the tripartite brains of vertebrates and euarthropods are homologous, then one would expect other taxa to share this structure. More generally, examination of other taxa can help in tracing the evolutionary history of brain structures. Tardigrades are an interesting lineage on which to test this hypothesis because they are closely related to euarthropods, and whether they have a tripartite brain or unipartite brain has recently been a focus of debate. RESULTS We tested this hypothesis by analyzing the expression patterns of six3, orthodenticle, pax6, unplugged, and pax2/5/8 during brain development in the tardigrade Hypsibius exemplaris-formerly misidentified as Hypsibius dujardini. These genes were expressed in a staggered anteroposterior order in H. exemplaris, similar to what has been reported for mice and flies. However, only six3, orthodenticle, and pax6 were expressed in the developing brain. Unplugged was expressed broadly throughout the trunk and posterior head, before the appearance of the nervous system. Pax2/5/8 was expressed in the developing central and peripheral nervous system in the trunk. CONCLUSION Our results buttress the conclusion of our previous study of Hox genes-that the brain of tardigrades is only homologous to the protocerebrum of euarthropods. They support a model based on fossil evidence that the last common ancestor of tardigrades and euarthropods possessed a unipartite brain. Our results are inconsistent with the hypothesis that the tripartite brain of euarthropods is directly homologous to the tripartite brain of vertebrates.
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Affiliation(s)
- Frank W. Smith
- Biology Department, University of North Florida, Jacksonville, FL USA
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
| | - Mandy Cumming
- Biology Department, University of North Florida, Jacksonville, FL USA
| | - Bob Goldstein
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
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13
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Eitel M, Francis WR, Varoqueaux F, Daraspe J, Osigus HJ, Krebs S, Vargas S, Blum H, Williams GA, Schierwater B, Wörheide G. Comparative genomics and the nature of placozoan species. PLoS Biol 2018; 16:e2005359. [PMID: 30063702 PMCID: PMC6067683 DOI: 10.1371/journal.pbio.2005359] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 06/28/2018] [Indexed: 12/30/2022] Open
Abstract
Placozoans are a phylum of nonbilaterian marine animals currently represented by a single described species, Trichoplax adhaerens, Schulze 1883. Placozoans arguably show the simplest animal morphology, which is identical among isolates collected worldwide, despite an apparently sizeable genetic diversity within the phylum. Here, we use a comparative genomics approach for a deeper appreciation of the structure and causes of the deeply diverging lineages in the Placozoa. We generated a high-quality draft genome of the genetic lineage H13 isolated from Hong Kong and compared it to the distantly related T. adhaerens. We uncovered substantial structural differences between the two genomes that point to a deep genomic separation and provide support that adaptation by gene duplication is likely a crucial mechanism in placozoan speciation. We further provide genetic evidence for reproductively isolated species and suggest a genus-level difference of H13 to T. adhaerens, justifying the designation of H13 as a new species, Hoilungia hongkongensis nov. gen., nov. spec., now the second described placozoan species and the first in a new genus. Our multilevel comparative genomics approach is, therefore, likely to prove valuable for species distinctions in other cryptic microscopic animal groups that lack diagnostic morphological characters, such as some nematodes, copepods, rotifers, or mites.
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Affiliation(s)
- Michael Eitel
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany
- Stiftung Tierärztliche Hochschule Hannover, Institut für Tierökologie und Zellbiologie, Ecology and Evolution, Hannover, Germany
| | - Warren R. Francis
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Frédérique Varoqueaux
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Jean Daraspe
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
| | - Hans-Jürgen Osigus
- Stiftung Tierärztliche Hochschule Hannover, Institut für Tierökologie und Zellbiologie, Ecology and Evolution, Hannover, Germany
| | - Stefan Krebs
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sergio Vargas
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Helmut Blum
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Gray A. Williams
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Hong Kong
| | - Bernd Schierwater
- Stiftung Tierärztliche Hochschule Hannover, Institut für Tierökologie und Zellbiologie, Ecology and Evolution, Hannover, Germany
- Sackler Institute for Comparative Genomics and Division of Invertebrate Zoology, American Museum of Natural History, New York, New York, United States of America
- Department of Ecology & Evolution, Yale University, New Haven, Connecticut, United States of America
| | - Gert Wörheide
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, Munich, Germany
- Staatliche Naturwissenschaftliche Sammlungen Bayerns (SNSB)–Bayerische Staatssammlung für Paläontologie und Geologie, Munich, Germany
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Kirwan JD, Graf J, Smolka J, Mayer G, Henze MJ, Nilsson DE. Low--resolution vision in a velvet worm (Onychophora). ACTA ACUST UNITED AC 2018; 221:jeb.175802. [PMID: 29626113 DOI: 10.1242/jeb.175802] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 03/15/2018] [Indexed: 01/21/2023]
Abstract
Onychophorans, also known as velvet worms, possess a pair of simple lateral eyes, and are a key lineage with regard to the evolution of vision. They resemble ancient Cambrian forms, and are closely related to arthropods, which boast an unrivalled diversity of eye designs. Nonetheless, the visual capabilities of onychophorans have not been well explored. Here, we assessed the spatial resolution of the onychophoran Euperipatoides rowelli using behavioural experiments, three-dimensional reconstruction, anatomical and optical examinations, and modelling. Exploiting their spontaneous attraction towards dark objects, we found that E. rowelli can resolve stimuli that have the same average luminance as the background. Depending on the assumed contrast sensitivity of the animals, we estimate the spatial resolution to be in the range 15-40 deg. This results from an arrangement where the cornea and lens project the image largely behind the retina. The peculiar ellipsoid shape of the eye in combination with the asymmetric position and tilted orientation of the lens may improve spatial resolution in the forward direction. Nonetheless, the unordered network of interdigitating photoreceptors, which fills the whole eye chamber, precludes high-acuity vision. Our findings suggest that adult specimens of E. rowelli cannot spot or visually identify prey or conspecifics beyond a few centimetres from the eye, but the coarse spatial resolution that the animals exhibited in our experiments is likely to be sufficient to find shelter and suitable microhabitats from further away. To our knowledge, this is the first evidence of resolving vision in an onychophoran.
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Affiliation(s)
- John D Kirwan
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Josefine Graf
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Jochen Smolka
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Georg Mayer
- Department of Zoology, University of Kassel, 34132 Kassel, Germany
| | - Miriam J Henze
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden .,Queensland Brain Institute, University of Queensland, St Lucia 4072, QLD, Australia
| | - Dan-Eric Nilsson
- Lund Vision Group, Department of Biology, Lund University, 223 62 Lund, Sweden
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Giribet G, Edgecombe GD. Current Understanding of Ecdysozoa and its Internal Phylogenetic Relationships. Integr Comp Biol 2017; 57:455-466. [DOI: 10.1093/icb/icx072] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Smith FW, Bartels PJ, Goldstein B. A Hypothesis for the Composition of the Tardigrade Brain and its Implications for Panarthropod Brain Evolution. Integr Comp Biol 2017; 57:546-559. [DOI: 10.1093/icb/icx081] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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17
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Feijoo M, Parada A. Macrosystematics of eutherian mammals combining HTS data to expand taxon coverage. Mol Phylogenet Evol 2017; 113:76-83. [PMID: 28487261 DOI: 10.1016/j.ympev.2017.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 05/04/2017] [Accepted: 05/04/2017] [Indexed: 02/04/2023]
Abstract
In the last few years high-throughput sequencing technologies have permitted significant advances in mammalian phylogenetic studies from a genomic perspective. However, these studies have been restricted to a sparse number of species with available reference genomes. Thus, several issues inside the eutherian mammals phylogeny remain unresolved. This may be due in part to limited taxon sampling, as taxonomic density is known to affect phylogenetic resolution. In this context, we present a protocol to increase taxon coverage using high-throughput sequencing data (RNA or DNA) generated for other biological studies and available in public databases. Following this procedure we addressed pending or controversial issues concerning the phylogenetic position of Dermoptera, Pholidota and Chiroptera, considering multiple and independent loci. Also for Chiroptera and Arctoidea we evaluated the relationships of the lineages that compose it. Although the maximum number of genes used is moderate (95), in some cases taxon coverage doubles that of previous related studies. Globally, all coalescent-based (STAR, MP-EST and ASTRAL) and concatenated (IQ-TREE and BEAST2) methods used for species tree reconstruction were consistent to each other and most of interrogated nodes received high statistical support.
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Affiliation(s)
- M Feijoo
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo CP 11400, Uruguay.
| | - A Parada
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia CP 5090000, Chile.
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