Genetic polymorphism of glutamine synthetase and delta-9 desaturase in families of Pacific oyster Crassostrea gigas and susceptibility to summer mortality
|Author(s)||David Elise1, Boudry Pierre2, Degremont Lionel2, 3, Tanguy Amelie4, Quere N1, 4, Samain Jean-Francois5, Moraga D1|
|Affiliation(s)||1 : Univ Bretagne Occidentale, Inst Univ Europeen Mer, LEMAR, CNRS,UMR 6539, F-29280 Plouzane, France.
2 : IFREMER, Ctr La Tremblade, Lab Genet & Pathol, F-17390 La Tremblade, France.
3 : Virginia Inst Marine Sci, Aquaculture Genet & Breeding Technol Ctr, Gloucester Point, VA 23062 USA.
4 : Lab Adaptat & Diversite Milieu Marin, UMR 7144, Biol Stn, F-29682 Roscoff, France.
5 : IFREMER, Ctr Brest, UMR Physiol & Ecophysiol Mollusques Marins, F-29280 Plouzane, France.
|Source||Journal of Experimental Marine Biology and Ecology (0022-0981) (Elsevier), 2007-10 , Vol. 349 , N. 2 , P. 272-283|
|WOS© Times Cited||8|
|Keyword(s)||SSCP, Mortality, Glutamine synthetase, Delta 9 desaturase, Crassostrea gigas|
|Abstract||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 1313 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. (C) 2007 Elsevier B.V. All rights reserved.|