Pacific oysters (Crassostrea gigas ) are the most widely cultivated shellfish species in the world. In the US, C. gigas is one of the main commercial shellfish species with total landings in 2022 reaching over 5 million pounds and a total value of over 31 million dollars (NOAA Fisheries report 2022). Because of its high commercial value, C. gigas is currently the target of efforts dedicated to improving production and quality . Knowing the sex of individual oysters at the time of spawn is critical for crossing of animals in breeding programs.
While Pacific oysters are dioecious (females and males are separate individuals) they lack any secondary sex characteristics making the sexing of individuals a significant challenge. Critical for the development of efficient sexing tools and for strategies to develop non-fertile oysters is the understanding of genetic and environmental control of sex in the Pacific oyster. We are using next generation sequencing of DNA and RNA combined with high-throughput qPCR to identify early markers of sex determination and working in the development of rapid assays. Currently, a set of five markers show strong promise as tools for molecular sexing. An update on ongoing research and findings will be presented.