Emerging Model Organisms

The Dogfish Scyliorhinus canicula: A Reference in Jawed Vertebrates

¹ CNRS UMR 6218 Immunologie et Embryologie Moléculaires, Université Sciences et Techniques d’Orléans, 45071 Orléans, France
² INSERM U565, F-75005 Paris, France, CNRS UMR5153, F-­75005 Paris, France, and Muséum National d’Histoire Naturelle, F-75005 Paris, France
³ Department of Craniofacial Development, Guy’s Hospital, King’s College London, United Kingdom
⁴ CNRS FR 2424, Station Biologique de Roscoff, 29682 Roscoff, France
⁵ Genoscope (CEA), F-91057 Evry, France, CNRS UMR 8030, F-­91057 Evry, France, and Université d’Evry, F-91057 Evry, France
⁶ CNRS UPR 2167, Centre de Génétique Moléculaire, F-91198 Gif sur Yvette, France
⁷ Department of Cell Biology and Ecology, Faculty of Biology, University of Santiago de Compostela, 15706 Santiago de Compostela, Spain
⁸ 150-a Dirac Science Library, School of Computational Science, Florida State University, Tallahassee, FL 32306, USA
⁹ UMR 100 IFREMER, Université de Caen Basse-Normandie "Physiologie et Ecophysiologie des Mollusques Marins," 14032 Caen, France

¹⁰Corresponding author (mazan{at}cnrs-orleans.fr)

INTRODUCTION

Due to their large size and long generation times, chondrichthyans have been largely ignored by geneticists. However, their key phylogenetic position makes them ideal subjects to study the molecular bases of the important morphological and physiological innovations that characterize jawed vertebrates. Such analyses are crucial to understanding the origin of the complex genetic mechanisms unraveled in osteichthyans. The small spotted dogfish Scyliorhinus canicula, a representative of the largest order of extant sharks, presents a number of advantages in this context. Due to its relatively small size among sharks, its abundance, and easy maintenance, the dogfish has been an important model in comparative anatomy and physiology for more than a century. Recently, revived interest has occurred with the development of large-scale transcriptomic and genomic resources, together with the establishment of facilities allowing massive egg and embryo production. These new tools open the way to molecular analyses of the elaborate physiological and sensory systems used by sharks. They also make it possible to take advantage of unique characteristics of these species, such as organ zonation, in analyses of cell proliferation and differentiation. Finally, they offer important perspectives to evolutionary developmental biology that will provide a better understanding of the origin and diversifications of jawed vertebrates. The dogfish whole-genome sequence, which may shortly become accessible, should establish this species as an essential shark reference, complementary to other chondrichthyan models. These analyses are likely to reveal an organism of an underestimated complexity, far from the primitive prototypical gnathostome anticipated in gradistic views.