The present project aims at improving the knowledge of the genetic and physiological bases of reproduction and associated processes of an economically important mollusk, the Pacific oyster Crassostrea gigas a species whose phylum is located at a key phylogenetic position among bilaterian animals.
The high fecundity of oysters, that produce large numbers of propagules and broadcast them into a hostile world, is commonly viewed as an evolutionary response to intense and unpredictable mortality at early life history stages (the “elm-oyster” proposed by Williams, 1975*). Evolution has shaped the physiology of these species to optimize their allocation to reproduction. As a result, gametogenesis has a major impact on several physiological functions, generating phenotypic and genetic trade-offs with growth and survival. Gametogenesis is also an important biological process to control in the context of aquaculture.
The project capitalizes on recent advances regarding genomic resources of C.gigas gathered within a unique oyster database rich of more than 50000 nucleotide sequences (hosted by Sigenae). A genetic screen will be carried-out by using high throughput transcriptomic technologies (microarray and quantitative RT-PCR) to identify genes specifically expressed during the different developmental stages of oyster gonads along an annual reproductive cycle. This will define relevant molecular markers connected to reproduction investment and in the genetic processes underlying sex determination for this successive and irregular protandric hermaphroditic species. Quantitative Trait Loci (QTL) of the allocation to reproduction of the oysters, giving a first step for understanding the genetic architecture of this trait, will be eased by the improvement of the density of the genetic map (with SNPs) and its link with the physical Radiation Hybrid (RH) map -a RH panel for the cupped oyster will be produced during this project. With the objective to connect genetic data with phenotypes, some relevant post-genomic methodologies will be adapted to our marine exotic model, due to its membership to the understudied clade of Lophotrochozoa for which no cell cultures are available. To approach the function of reproduction relevant genes, we will focus on established technologies having proven their achievement in animal models i.e. RNA interference and reverse endocrinology and pharmacology methodologies. These challenging methodological issues should give unique insights into the functional involvement of key genes in gametogenesis of a Lophotrochozoan animal. They also constitute a prerequisite for current and future exploitation of C gigas genomic resources as they will help correlate genetic expression to function and/or phenotype.
Monsieur Pascal FAVREL (UNIVERSITE DE CAEN - BASSE-NORMANDIE)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
UNIVERSITE DE BRETAGNE OCCIDENTALE
CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE BRETAGNE ET PAYS- DE-LA-LOIRE
INSTITUT FRANCAIS DE RECHERCHE POUR L'EXPLOITATION DE LA MER (IFREMER)
UNIVERSITE DE CAEN - BASSE-NORMANDIE
Help of the ANR 483,130 euros
Beginning and duration of the scientific project: - 48 Months