Crassostrea gigas

    The oyster Crassostrea gigas has wide geographic distribution and, for many years, represents the highest annual production of any aquatic organism. The economic importance of oysters motivates a great deal of biological research, which provides the most immediate scientific rationales for sequencing ESTs. Strong rationales also come from membership of oyster to the Lophotrochozoa, an understudied branch of bilaterian animals with limited molecular data today. With high fecundity and concomitantly high DNA polymorphism, this species also constitutes a good model for population and genetic studies. Finally, oysters play an important sentinel role in estuarine and coastal marine habitats, where increasing human activities interfere with exploited populations that may suffer from mortality related to diseases and stress.

The C. gigas EST sequences generated by the Genoscope will:

• help identify, in a much straightforward way, new pertinent key genes for functional purposes (physiology of growth, reproduction and development, immunity). Those will provide new tools to improve this species by genetic selection.
• be used for evolutionary studies by comparison with orthologous sequences from other mollusc species, other Lophotrochozoans or other bilaterian animals.
• complement an initial 9059 unigene microarray currentlyavailable. The resulting microarray will be more representative of the whole transcriptome and therefore extremely useful in transcriptomic programs for investigating global gene expression changes. This should help deliver a more integrative picture of the gene networks activated in the context of particular ecophysiological constrains (either in controlled conditions or in the field) and help reveal major gene networks contributing to a given physiological process under study.
• be used to identify SNPs for further genetic studies in both experimental and field populations, for population genetic and mapping studies.
• be used for recognition of haemocyte tags produced by SAGE technology.
• help to boost the sequencing of whole genome, as currently proposed by an international consortium.