A comprehensive knowledge of Crassostrea gigas oyster reproduction processes is essential to optimize controlled reproduction in hatchery. This study aimed to determine the origin and the mechanisms of annual renewal of germ cells, still unknown in oysters, and the influence of temperature and photoperiod parameters on the regulation of the reproductive cycle. We characterized an orthologue of the vasa gene, the Oyvlg (Oyster vasa-like gene), the first germ cell specific marker isolated in molluscs. This marker was used to study C. gigas germline development. Oyster germ cells appeared specified during early development from mesentoblast 4d, as primordial germ cells (PGCs) determined by maternal cytoplasmic determinants, including Oyvlg mRNA. In adult... |