Evolving Pathways Key Themes in Evolutionary Developmental Biology

Total Page:16

File Type:pdf, Size:1020Kb

Evolving Pathways Key Themes in Evolutionary Developmental Biology Evolving Pathways Key Themes in Evolutionary Developmental Biology Evolutionary developmental biology, or ‘evo-devo’, is the study of the relationship between evolution and development. Dealing specifically with the generative mechanisms of organismal form, evo-devo goes straight to the core of the developmental origin of variation, the raw material on which natural selection (and random drift) can work. Evolving Pathways responds to the growing volume of data in this field, with its potential to answer fundamental questions in biology, by fuelling debate through contributions that represent a diversity of approaches. Topics range from developmental genetics to comparative morphology of animals and plants alike, including palaeontology. Researchers and graduate students will find this book a valuable overview of current research as we begin to fill a major gap in our perception of evolutionary change. ALESSANDRO MINELLI is currently Professor of Zoology at the University of Padova, Italy. An honorary fellow of the Royal Entomological Society, he was a founding member and Vice-President of the European Society for Evolutionary Biology. He has served as President of the International Commission on Zoological Nomenclature, and is on the editorial board of multiple learned journals, including Evolution & Development. He is the author of The Development of Animal Form (2003). GIUSEPPE FUSCO is Assistant Professor of Zoology at the University of Padova, Italy, where he teaches evolutionary biology. His main research work is in the morphological evolution and post-embryonic development of arthropods, with particular reference to the role of segmentation in the Chilopoda. Evolving Pathways Key Themes in Evolutionary Developmental Biology Edited by ALESSANDRO MINELLI GIUSEPPE FUSCO University of Padova, Italy CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521875004 © Cambridge University Press 2008 This publication is in copyright. Subject to statutory exception and to the provision of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published in print format 2008 ISBN-13 978-0-511-37860-7 eBook (NetLibrary) ISBN-13 978-0-521-87500-4 hardback Cambridge University Press has no responsibility for the persistence or accuracy of urls for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. Contents Contributors page ix Preface xiii Introduction: Pathways of change xv Part I1 Thinking about evolution by taking development on board 1 Evo-devo as a discipline5 GERD B. MÜLLER 2 Making evolutionary predictions about the structure of development and morphology: beyond the neo-Darwinian and constraints paradigms 31 ISAAC SALAZAR- CIUDAD 3 Conflicting hypotheses on the nature of mega-evolution 50 WALLACE ARTHUR 4 Prospects of evo-devo for linking pattern and process in the evolution of morphospace 62 PAUL M. BRAKEFIELD 5 The molecular biology underlying developmental evolution 80 CLAUDIO R. ALONSO 6 Evo-devo’s identity: from model organisms to developmental types 100 RONALD A. JENNER v vi Contents Part II 121 Evo-devo: methods and materials 7 A pragmatic approach for selecting evo-devo model species in amniotes 123 ATHANASIA C. TZIKA AND MICHEL C. MILINKOVITCH 8 On comparisons and causes in evolutionary developmental biology 144 GERHARD SCHOLTZ 9 Evolution and development: towards a synthesis of macro- and micro-evolution with ecology 160 HANS ZAUNER AND RALF J. SOMMER 10 When is a Hox gene not a Hox gene? The importance of gene nomenclature 175 DAVID E. K . FERRIER 11 Plants are used to having identity crises 194 ROLF RUTISHAUSER, VALENTIN GROB AND EVELIN PFEIFER Part III 215 Evolving diversity 12 Unravelling body plan and axial evolution in the Bilateria with molecular phylogenetic markers 217 JAUME BAGUÑÀ, PERE MARTINEZ, JORDI PAPS AND MARTA RIUTORT 13 Are transposition events at the origin of the bilaterian Hox complexes? 239 JEAN S. DEUTSCH AND PHILIPPE LOPEZ 14 Many roads lead to Rome: different ways to construct a nematode 261 EINHARD SCHIERENBERG AND JENS SCHULZE 15 Basal euarthropod development: a fossil-based perspective 281 NIGEL C. HUGHES, JOACHIM T. HAUG AND DIETER WALOSZEK 16 Developmental transitions during the evolution of plant form 299 JANE A. LANGDALE AND C. JILL HARRISON Contents vii Part IV 317 Evolving body features 17 Urbisexuality: the evolution of bilaterian germ cell specification and reproductive systems 321 CASSANDRA G. M . EXTAVOUR 18 Thoughts and speculations on the ancestral arthropod segmentation pathway 343 ARIEL D. CHIPMAN 19 Evolution of neurogenesis in arthropods 359 ANGELIKA STOLLEWERK 20 Arthropod appendages: a prime example for the evolution of morphological diversity and innovation 381 NIKOLA- MICHAEL PRPIC AND WIM G. M . DAMEN 21 Ontogeny of the spiralian brain 399 CLAUS NIELSEN Index 417 Contributors Claudio R. Alonso University of Cambridge, Department of Zoology, Cambridge, United Kingdom Wallace Arthur National University of Ireland at Galway, Department of Zoology, Galway, Ireland Jaume Baguñà Universitat de Barcelona, Facultat de Biologia, Departament de Genètica, Barcelona, Spain Paul M. Brakefield Leiden University, Institute of Biology, Leiden, The Netherlands Ariel D. Chipman The Hebrew University of Jerusalem, Department of Evolution Systematics and Ecology, Jerusalem, Israel Wim G. M. Damen Universität zu Köln, Institut für Genetik, Köln, Germany Jean S. Deutsch Université Pierre et Marie Curie (Paris 6), Biologie du Développement and CNRS, Paris, France Cassandra G. M. Extavour Harvard University, Department of Organismic and Evolutionary Biology, Cambridge, Massachusetts, United States of America ix x Contributors David E. K. Ferrier University of St Andrews, The Gatty Marine Laboratory, St Andrews, Scotland, United Kingdom Valentin Grob Universität Zürich, Institut für Systematische Botanik und Bota- nischer Garten, Zürich, Switzerland C. Jill Harrison University of Oxford, Department of Plant Sciences, Oxford, United Kingdom Joachim T. Haug Universität Ulm, Sektion Biosystematische Dokumentation, Ulm, Germany Nigel C. Hughes University of California Riverside, Department of Earth Sciences, Riverside, California, United States of America Ronald A. Jenner University of Bath, Department of Biology and Biochemistry, Bath, United Kingdom Jane A. Langdale University of Oxford, Department of Plant Sciences, Oxford, United Kingdom Philippe Lopez Université Pierre et Marie Curie (Paris 6), Systématique Adaptation Évolution and CNRS, Paris, France Pere Martinez Universitat de Barcelona, Facultat de Biologia, Departament de Genètica, Barcelona, Spain Michel C. Milinkovitch Université Libre de Bruxelles, Institute for Molecular Biology & Medicine, Laboratory of Evolutionary Genetics, Gosselies, Belgium Gerd B. Müller University of Vienna, Department of Theoretical Biology, Vienna, Austria, and Konrad Lorenz Institute for Evolution and Cognition Research, Altenberg, Austria Contributors xi Claus Nielsen University of Copenhagen, The Natural History Museum of Denmark, Zoological Museum, Copenhagen, Denmark Jordi Paps Universitat de Barcelona, Facultat de Biologia, Departament de Genètica, Barcelona, Spain Evelin Pfeifer Universität Zürich, Institut für Systematische Botanik und Botanischer Garten, Zürich, Switzerland Nikola-Michael Prpic Georg-August-Universität, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Abteilung für Entwicklungsbio- logie, Göttingen, Germany Marta Riutort Universitat de Barcelona, Facultat de Biologia, Departament de Genètica, Barcelona, Spain Rolf Rutishauser Universität Zürich, Institut für Systematische Botanik und Botanischer Garten, Zürich, Switzerland Isaac Salazar-Ciudad University of Helsinki, Institute of Biotechnology, Developmental Biology Program, Helsinki, Finland Einhard Schierenberg Universität zu Köln, Institut für Zoologie, Köln, Germany Gerhard Scholtz Humboldt-Universität zu Berlin, Institut für Biologie/ Vergleichende Zoologie, Berlin, Germany Jens Schulze Universität zu Köln, Institut für Zoologie, Köln, Germany Ralf J. Sommer Max-Planck Institute for Developmental Biology, Department for Evolutionary Biology, Tübingen, Germany Angelika Stollewerk Queen Mary, University of London, School of Biological and Chemical Sciences, United Kingdom xii Contributors Athanasia C. Tzika Université Libre de Bruxelles, Institute for Molecular Biology & Medicine, Laboratory of Evolutionary Genetics, Gosselies, Belgium Dieter Waloszek Universität Ulm, Sektion Biosystematische Dokumentation, Ulm, Germany Hans Zauner Max-Planck Institute for Developmental Biology, Department for Evolutionary Biology, Tübingen, Germany Preface Two important events marked the year 2006 in the still short history of evolutionary developmental biology. The first European Workshop on Evolutionary Developmental Biology, held in Venice on 5–6 May 2006, offered some 30 researchers from most of the European teams active in this field a timely perspective on key issues in the disci- pline, and opened a lively discussion on where to move next, in terms of problems, model organisms, and levels
Recommended publications
  • Functional Analysis of the Homeobox Gene Tur-2 During Mouse Embryogenesis
    Functional Analysis of The Homeobox Gene Tur-2 During Mouse Embryogenesis Shao Jun Tang A thesis submitted in conformity with the requirements for the Degree of Doctor of Philosophy Graduate Department of Molecular and Medical Genetics University of Toronto March, 1998 Copyright by Shao Jun Tang (1998) National Library Bibriothèque nationale du Canada Acquisitions and Acquisitions et Bibiiographic Services seMces bibliographiques 395 Wellington Street 395, rue Weifington OtbawaON K1AW OttawaON KYAON4 Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence alIowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distri%uteor sell reproduire, prêter' distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/nlm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fkom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. Functional Analysis of The Homeobox Gene TLr-2 During Mouse Embryogenesis Doctor of Philosophy (1998) Shao Jun Tang Graduate Department of Moiecular and Medicd Genetics University of Toronto Abstract This thesis describes the clonhg of the TLx-2 homeobox gene, the determination of its developmental expression, the characterization of its fiuiction in mouse mesodem and penpheral nervous system (PNS) developrnent, the regulation of nx-2 expression in the early mouse embryo by BMP signalling, and the modulation of the function of nX-2 protein by the 14-3-3 signalling protein during neural development.
    [Show full text]
  • Number of Living Species in Australia and the World
    Numbers of Living Species in Australia and the World 2nd edition Arthur D. Chapman Australian Biodiversity Information Services australia’s nature Toowoomba, Australia there is more still to be discovered… Report for the Australian Biological Resources Study Canberra, Australia September 2009 CONTENTS Foreword 1 Insecta (insects) 23 Plants 43 Viruses 59 Arachnida Magnoliophyta (flowering plants) 43 Protoctista (mainly Introduction 2 (spiders, scorpions, etc) 26 Gymnosperms (Coniferophyta, Protozoa—others included Executive Summary 6 Pycnogonida (sea spiders) 28 Cycadophyta, Gnetophyta under fungi, algae, Myriapoda and Ginkgophyta) 45 Chromista, etc) 60 Detailed discussion by Group 12 (millipedes, centipedes) 29 Ferns and Allies 46 Chordates 13 Acknowledgements 63 Crustacea (crabs, lobsters, etc) 31 Bryophyta Mammalia (mammals) 13 Onychophora (velvet worms) 32 (mosses, liverworts, hornworts) 47 References 66 Aves (birds) 14 Hexapoda (proturans, springtails) 33 Plant Algae (including green Reptilia (reptiles) 15 Mollusca (molluscs, shellfish) 34 algae, red algae, glaucophytes) 49 Amphibia (frogs, etc) 16 Annelida (segmented worms) 35 Fungi 51 Pisces (fishes including Nematoda Fungi (excluding taxa Chondrichthyes and (nematodes, roundworms) 36 treated under Chromista Osteichthyes) 17 and Protoctista) 51 Acanthocephala Agnatha (hagfish, (thorny-headed worms) 37 Lichen-forming fungi 53 lampreys, slime eels) 18 Platyhelminthes (flat worms) 38 Others 54 Cephalochordata (lancelets) 19 Cnidaria (jellyfish, Prokaryota (Bacteria Tunicata or Urochordata sea anenomes, corals) 39 [Monera] of previous report) 54 (sea squirts, doliolids, salps) 20 Porifera (sponges) 40 Cyanophyta (Cyanobacteria) 55 Invertebrates 21 Other Invertebrates 41 Chromista (including some Hemichordata (hemichordates) 21 species previously included Echinodermata (starfish, under either algae or fungi) 56 sea cucumbers, etc) 22 FOREWORD In Australia and around the world, biodiversity is under huge Harnessing core science and knowledge bases, like and growing pressure.
    [Show full text]
  • In Worms Geoff Read NIWA New Zealand
    Brussels, 28-30 September Polychaeta (Annelida) in WoRMS Geoff Read NIWA New Zealand www.marinespecies.org/polychaeta/index.php Context interface Swimming — an unexpected skill of Polychaeta Acrocirridae Alciopidae Syllidae Nereididae Teuthidodr ilus = squidworm Acrocirridae Polynoidae Swima bombiviridis Syllidae Total WoRMS Polychaeta records, excluding fossils 91 valid families. Entries >98% editor checked, except Echiura (69%) Group in WoRMS all taxa all species valid species names names names Class Polychaeta 23,872 20,135 11,615 Subclass Echiura 296 234 197 Echiura were recently a Subclass Errantia 12,686 10,849 6,210 separate phylum Subclass Polychaeta incertae sedis 354 265 199 Subclass Sedentaria 10,528 8,787 5,009 Non-marine Polychaeta 28 16 (3 terrestrial) Class Clitellata* 1601 1086 (279 Hirudinea) *Total valid non-leech clitellates~5000 spp, 1700 aquatic. (Martin et al. 2008) Annelida diversity "It is now clear that annelids, in addition to including a large number of species, encompass a much greater disparity of body plans than previously anticipated, including animals that are segmented and unsegmented, with and without parapodia, with and without chaetae, coelomate and acoelomate, with straight guts and with U-shaped digestive tracts, from microscopic to gigantic." (Andrade et al. 2015) Andrade et al (2015) “Articulating “archiannelids”: Phylogenomics and annelid relationships, with emphasis on meiofaunal taxa.” Molecular Biology and Evolution, efirst Myzostomida (images Summers et al)EV Nautilus: Riftia Semenov: Terebellidae Annelida latest phylogeny “… it is now well accepted that Annelida includes many taxa formerly considered different phyla or with supposed affiliations with other animal groups, such as Sipuncula, Echiura, Pogonophora and Vestimentifera, Myzostomida, or Diurodrilida (Struck et al.
    [Show full text]
  • Bodyplan Diversification in Crinoid-Associated Myzostomes (Myzostomida, Protostomia)
    Invertebrate Biology 128(3): 283–301. r 2009, The Authors Journal compilation r 2009, The American Microscopical Society, Inc. DOI: 10.1111/j.1744-7410.2009.00172.x Bodyplan diversification in crinoid-associated myzostomes (Myzostomida, Protostomia) De´borah Lanterbecq,1,a Greg W. Rouse,2 and Igor Eeckhaut1 1 Marine Biology Laboratory, University of Mons-Hainaut, 7000 Mons, Hainaut, Belgium 2 Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0202, USA Abstract. When free-living organisms evolve into symbiotic organisms (parasites, commen- sals, or mutualists), their bodyplan is often dramatically modified as a consequence. The present work pertains to the study of this process in a group of marine obligate symbiotic worms, the Myzostomida. These are mainly ectocommensals and are only associated with echinoderms, mostly crinoids. Their usual textbook status as a class of the Annelida is gen- erally accepted, although recent molecular phylogenetic studies have raised doubts on their relationships with other metazoans, and the question of their status remains open. Here, we reconstruct the evolution of their bodyplans by mapping 14 external morphological charac- ters (analyzed using scanning electron microscopy) onto molecular phylogenies using max- imum parsimony (MP) and maximum likelihood (ML) optimality criteria. Rooted MP, ML, and Bayesian phylogenetic trees were obtained by analyzing the nucleotide sequences of cytochrome oxidase subunit I, 18S rDNA, and 16S rDNA genes, separately and
    [Show full text]
  • Alternative Splicing Modulates Ubx Protein Function in Drosophila Melanogaster
    Copyright Ó 2010 by the Genetics Society of America DOI: 10.1534/genetics.109.112086 Alternative Splicing Modulates Ubx Protein Function in Drosophila melanogaster Hilary C. Reed,* Tim Hoare,† Stefan Thomsen,‡ Thomas A. Weaver,† Robert A. H. White,† Michael Akam* and Claudio R. Alonso‡,1 *Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom, †Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom and ‡School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom Manuscript received November 13, 2009 Accepted for publication December 17, 2009 ABSTRACT The Drosophila Hox gene Ultrabithorax (Ubx) produces a family of protein isoforms through alternative splicing. Isoforms differ from one another by the presence of optional segments—encoded by individual exons—that modify the distance between the homeodomain and a cofactor-interaction module termed the ‘‘YPWM’’ motif. To investigate the functional implications of Ubx alternative splicing, here we analyze the in vivo effects of the individual Ubx isoforms on the activation of a natural Ubx molecular target, the decapentaplegic (dpp) gene, within the embryonic mesoderm. These experiments show that the Ubx isoforms differ in their abilities to activate dpp in mesodermal tissues during embryogenesis. Furthermore, using a Ubx mutant that reduces the full Ubx protein repertoire to just one single isoform, we obtain specific anomalies affecting the patterning of anterior abdominal muscles, demonstrating that Ubx isoforms are not functionally interchangeable during embryonic mesoderm development. Finally, a series of experiments in vitro reveals that Ubx isoforms also vary in their capacity to bind DNA in presence of the cofactor Extradenticle (Exd).
    [Show full text]
  • Remarkable Convergent Evolution in Specialized Parasitic Thecostraca (Crustacea)
    Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea) Pérez-Losada, Marcos; Høeg, Jens Thorvald; Crandall, Keith A Published in: BMC Biology DOI: 10.1186/1741-7007-7-15 Publication date: 2009 Document version Publisher's PDF, also known as Version of record Citation for published version (APA): Pérez-Losada, M., Høeg, J. T., & Crandall, K. A. (2009). Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea). BMC Biology, 7(15), 1-12. https://doi.org/10.1186/1741-7007-7-15 Download date: 25. Sep. 2021 BMC Biology BioMed Central Research article Open Access Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea) Marcos Pérez-Losada*1, JensTHøeg2 and Keith A Crandall3 Address: 1CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Portugal, 2Comparative Zoology, Department of Biology, University of Copenhagen, Copenhagen, Denmark and 3Department of Biology and Monte L Bean Life Science Museum, Brigham Young University, Provo, Utah, USA Email: Marcos Pérez-Losada* - [email protected]; Jens T Høeg - [email protected]; Keith A Crandall - [email protected] * Corresponding author Published: 17 April 2009 Received: 10 December 2008 Accepted: 17 April 2009 BMC Biology 2009, 7:15 doi:10.1186/1741-7007-7-15 This article is available from: http://www.biomedcentral.com/1741-7007/7/15 © 2009 Pérez-Losada et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
    [Show full text]
  • A Possible 150 Million Years Old Cirripede Crustacean Nauplius and the Phenomenon of Giant Larvae
    Contributions to Zoology, 86 (3) 213-227 (2017) A possible 150 million years old cirripede crustacean nauplius and the phenomenon of giant larvae Christina Nagler1, 4, Jens T. Høeg2, Carolin Haug1, 3, Joachim T. Haug1, 3 1 Department of Biology, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg- Martinsried, Germany 2 Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark 3 GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Straße 10, 80333 Munich, Germany 4 E-mail: [email protected] Key words: nauplius, metamorphosis, palaeo-evo-devo, Cirripedia, Solnhofen lithographic limestones Abstract The possible function of giant larvae ................................ 222 Interpretation of the present case ....................................... 223 The larval phase of metazoans can be interpreted as a discrete Acknowledgements ....................................................................... 223 post-embryonic period. Larvae have been usually considered to References ...................................................................................... 223 be small, yet some metazoans possess unusually large larvae, or giant larvae. Here, we report a possible case of such a giant larva from the Upper Jurassic Solnhofen Lithographic limestones (150 Introduction million years old, southern Germany), most likely representing an immature cirripede crustacean (barnacles and their relatives). The single specimen was documented with up-to-date
    [Show full text]
  • Barnacle Editor Workshop
    Barnacle Editor Workshop VLIZ InnovOcean Site Wandelaarkaai 7 – entrance Pakhuis 61 (UNESCO) B-8400 Oostende, Belgium February 24-28, 2020 Final Report Barnacle Participants: Keith Crandall, Meeting Organizer, George Washington University, Washington, DC USA Jens Hoeg, University of Copenhagen, Copenhagen, Denmark Marcos Pérez-Losada, George Washington University, Washington, DC USA Benny Chan, Academia Sinica, Taipei, Taiwan Henrick Glenner, University of Bergen, Bergen, Norway Andy Gale, University of Portsmouth, Portsmouth, United Kingdom Niklas Dreyer, Academia Sinica, Taipei, Taiwan WoRMS Data Management Team (DMT): Stefanie Dekeyzer (Meeting Coordinator) Bart Vanhoorne Wim Decock Leen Vandepitte Target Group: The barnacles – more specifically, the broader group of Thecostraca including the traditional barnacles (Cirripedia) as well as the related groups of Facetotecta and Ascothoracida. The thecostracan barnacles rank among the most commonly encountered marine crustaceans in the world. They deviate from almost all other Crustacea in that only the larvae are free-living, while the adults are permanently sessile and morphologically highly specialized as filter feeders or parasites. In the most recent classifications of the crustacean Maxillopoda 1 and latest phylogenetic analyses 2-4 the Thecostraca sensu Grygier 5, comprising the Facetotecta, Ascothoracida, and Cirripedia, form monophyletic assemblages. Barnacle phylogenetics has advanced greatly over the last 10 years. Nonetheless, the relationships and taxonomic status of some groups within these three infraclasses are still a matter of debate. While the barnacles where the focus of Darwin’s detailed taxonomic work, there has not been a comprehensive review of the species of barnacles as a whole since Darwin. As a consequence, the barnacle entries within the WoRMS Database is woefully out of date taxonomically and missing many, many species and higher taxa.
    [Show full text]
  • 3.2.2.11. Familia Salicaceae (Incluyendo a Flacourtiaceae) 3.2.2.11.A
    97 3.2.2.11. Familia Salicaceae (incluyendo a Flacourtiaceae) 3.2.2.11.a. Características ¾ Porte: arbustos o árboles. ¾ Hojas: alternas, simples, con estípulas, en general caducas. ¾ Flores: pequeñas, imperfectas, diclino-dioicas, en amentos erguidos o péndulos. En Azara, Cassearia, Banara, Xylosma pequeñas, solitarias, axilares o en cimas, perfectas o imperfectas, hipóginas, raro períginas o epíginas. ¾ Perianto: aperiantadas, protegidas por una bráctea, con un cáliz vestigial, en Salix se reduce a nectarios. En Azara, Cassearia, Banara, Xylosma cáliz con 3-15 sépalos libres; corola, 3-15 pétalos, disco nectarífero intrastaminal o extraestaminal. ¾ Estambres: 2-varios. En Azara, Cassearia, Banara, Xylosma 4-∞, libres, anteras ditecas. ¾ Gineceo: ovario súpero, 2-10 carpelos unidos, unilocular, pluriovulado, óvulos 1-∞, parietales, estilos libres, parcialmente soldados o estilo único, estigmas. ¾ Fruto: cápsula dehiscente conteniendo semillas lanosas. En Azara, Cassearia, Banara, Xylosma baya, cápsula loculicida o drupa. ¾ Semillas: con pelos, sin endosperma y con embrión recto. Azara, Cassearia, Banara, Xylosma semillas ariladas. Flor estaminada, flor pistilada, brácteas y nectario de la flor estaminada de Salix caroliniana Flor estaminada y flor pistilada de Azara microphylla (Dibujos adaptados de Boelcke y Vizinis, 1987 por Daniel Cian) Diversidad Vegetal Facultad de Ciencias Exactas y Naturales y Agrimensura (UNNE) EUDICOTILEDONEAS ESCENCIALES-Clado Rosides-Eurosides I-Malpighiales: Salicaceae (inc. Flacourtiaceae) 98 3.2.2.11.b. Biología floral y/o Fenología La polinización puede ser anemófila, en Populus, o por insectos atraídos por el néctar, que producen los nectarios, ubicados en la base de la flor. Especies del género Salix son polinizadas por abejas melíferas. En las especies entomófilas los órganos nectaríferos son foliares, residuos del perianto que desapareció (Vogel, com.
    [Show full text]
  • Myzostomida: a Link Between Trochozoans and Flatworms?
    doi 10.1098/rspb.2000.1154 Myzostomida: a link between trochozoans and atworms? Igor Eeckhaut1*, Damhnait McHugh2, Patrick Mardulyn3, Ralph Tiedemann3, Daniel Monteyne3, Michel Jangoux1,4 and Michel C. Milinkovitch3{ 1Marine Biology Laboratory, University of Mons, B-7000 Mons, Belgium 2Department of Biology, Colgate University, Hamilton, NY 13346, USA 3Unit of Evolutionary Genetics, Free University of Brussels, B- 6041 Gosselies, Belgium 4Marine Biology Laboratory, B-1050 Free University of Brussels, Belgium Myzostomids are obligate symbiotic invertebrates associated with echinoderms with a fossil record that extends to the Ordovician period. Due to their long history as host-speci¢c symbionts, myzostomids have acquired a unique anatomy that obscures their phylogenetic a¤nities to other metazoans: they are incom- pletely segmented, parenchymous, acoelomate organisms with chaetae and a trochophore larva. Today, they are most often classi¢ed within annelids either as an aberrant family of polychaetes or as a separate class. We inferred the phylogenetic position of the Myzostomida by analysing the DNA sequences of two slowly evolving nuclear genes: the small subunit ribosomal RNA and elongation factor-1a. All our analyses congruently indicated that myzostomids are not annelids but suggested instead that they are more closely related to £atworms than to any trochozoan taxon. These results, together with recent analyses of the myzostomidan ultrastructure, have signi¢cant implications for understanding the evolu- tion of metazoan body plans, as major characters (segmentation, coeloms, chaetae and trochophore larvae) might have been independently lost or gained in di¡erent animal phyla. Keywords: Metazoa; Myzostomida; Annelida; evolution; molecular phylogeny; symbiosis or Stelechopoda (i.e. a taxon grouping myzostomids with 1.
    [Show full text]
  • HOX CLUSTER INTERGENIC SEQUENCE EVOLUTION by JEREMY DON RAINCROW a Dissertation Submitted to the Graduate School-New Brunswick R
    HOX CLUSTER INTERGENIC SEQUENCE EVOLUTION By JEREMY DON RAINCROW A Dissertation submitted to the Graduate School-New Brunswick Rutgers, The State University of New Jersey and The Graduate School of Biomedical Sciences University of Medicine and Dentistry of New Jersey in partial fulfillment of the requirements for the degree of Doctor of Philosophy Graduate Program in Cell and Developmental Biology written under the direction of Chi-hua Chiu and approved by ______________________________________________ ______________________________________________ ______________________________________________ ______________________________________________ New Brunswick, New Jersey October 2010 ABSTRACT OF THE DISSERTATION HOX GENE CLUSTER INTERGENIC SEQUENCE EVOLUTION by JEREMY DON RAINCROW Dissertation Director: Chi-hua Chiu The Hox gene cluster system is highly conserved among jawed-vertebrates. Specifically, the coding region of Hox genes along with their spacing and occurrence is highly conserved throughout gnathostomes. The intergenic regions of these clusters however are more variable. During the construction of a comprehensive non-coding sequence database we discovered that the intergenic sequences appear to also be highly conserved among cartilaginous and lobe-finned fishes, but much more diverged and dynamic in the ray-finned fishes. Starting at the base of the Actinopterygii a turnover of otherwise highly conserved non-coding sequences begins. This turnover is extended well into the derived ray-finned fish clade, Teleostei. Evidence from our population genetic study suggests this turnover, which appears to be due mainly to loosened constraints at the macro-evolutionary level, is highlighted by evidence of strong positive selection acting at the micro-evolutionary level. During the construction of the non-coding sequence database we also discovered that along with evidence of both relaxed constraints and positive selection emerges a pattern of transposable elements found within the Hox gene cluster system.
    [Show full text]
  • Homeotic Gene Action in Embryonic Brain Development of Drosophila
    Development 125, 1579-1589 (1998) 1579 Printed in Great Britain © The Company of Biologists Limited 1998 DEV1254 Homeotic gene action in embryonic brain development of Drosophila Frank Hirth, Beate Hartmann and Heinrich Reichert* Institute of Zoology, University of Basel, Rheinsprung 9, CH-4051 Basel, Switzerland *Author for correspondence (e-mail: [email protected]) Accepted 18 February; published on WWW 1 April 1998 SUMMARY Studies in vertebrates show that homeotic genes are absence of labial, mutant cells are generated and positioned involved in axial patterning and in specifying segmental correctly in the brain, but these cells do not extend axons. identity of the embryonic hindbrain and spinal cord. To Additionally, extending axons of neighboring wild-type gain further insights into homeotic gene action during CNS neurons stop at the mutant domains or project ectopically, development, we here characterize the role of the homeotic and defective commissural and longitudinal pathways genes in embryonic brain development of Drosophila. We result. Immunocytochemical analysis demonstrates that first use neuroanatomical techniques to map the entire cells in the mutant domains do not express neuronal anteroposterior order of homeotic gene expression in the markers, indicating a complete lack of neuronal identity. Drosophila CNS, and demonstrate that this order is An alternative glial identity is not adopted by these mutant virtually identical in the CNS of Drosophila and mammals. cells. Comparable effects are seen in Deformed mutants but We then carry out a genetic analysis of the labial gene in not in other homeotic gene mutants. Our findings embryonic brain development. Our analysis shows that demonstrate that the action of the homeotic genes labial loss-of-function mutation and ubiquitous overexpression of and Deformed are required for neuronal differentiation in labial results in ectopic expression of neighboring the developing brain of Drosophila.
    [Show full text]