Genetic polymorphism of glutamine synthetase and delta-9 desaturase in families of Pacific oyster Crassostrea gigas and susceptibility to summer mortality

• Published in: Journal of Experimental Marine Biology and Ecology
• Main Authors: David, Elise, Boudry, Pierre, Degremont, Lionel, Tanguy, Arnaud, Quéré, Nolwenn, Samain, Jean-François, Moraga, Dario
• Other Authors: Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité Amélioration génétique, Santé animale et Environnement (AGSAE), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Aquaculture genetics and Breeding Technology Center, Virginia Institute of Marine Science (VIMS), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff Roscoff (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Physiologie et Ecophysiologie des Mollusques Marins (PE2M), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: Crassostrea gigas; Delta-9 desaturase; Glutamine synthetase; Mortality; SSCP; [SDE]Environmental Sciences; Pacific; Pacific oyster
• Online Access: https://hal.univ-brest.fr/hal-00667057; https://doi.org/10.1016/j.jembe.2007.05.016

International audience Large-scale mortality events have been observed in Pacific oyster Crassostrea gigas on the west coast of France since the early 1980s, particularly during summer. In order to understand the causes of this mortality, two generations of oysters from single-pair matings were studied in three sites on the French Atlantic coast (Baie-des-Veys, Auray and Ronce-les-Bains). The present paper examines the role of two candidate genes in the susceptibility of oysters to summer mortality, and the selective pressure exerted by such mortality on their polymorphism. Glutamine synthetase (amino-acid metabolism) and delta-9 desaturase (lipid metabolism) genes were studied in the successive generations, using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP). Observed and expected genotypic frequencies were compared. Three different alleles were detected for the glutamine synthetase gene and two for delta-9 desaturase. Allele C of glutamine synthetase seemed to be counter-selected in some second generation families. Allele B of delta-9 desaturase gene was potentially counter-selected at Auray in the families showing higher mortality, and strong selection against BB homozygotes was observed. These observations led us to conclude that any selective effect of summer mortality on allele C of glutamine synthetase gene or allele B of delta-9 desaturase gene could be mediated either directly or via linkage to other loci involved in physiological pathways affecting susceptibility.