GENETIC-ASPECTS OF DISEASE RESISTANCE IN OYSTERS

Like other phenotypic traits, resistance to disease is generally subje ct to underlying genotypic variability. This may come about indirectly , as a result of variation in overall physiology or in life history ch aracteristics, or may be more directly attributable to variation in ce llular or biochemical mechanisms. We summarize here our current unders tanding of genetic influences on physiological and life history variat ion in Crassostrea and review the evidence available to date on intra- and interspecific generic variation in disease resistance, with empha sis on Perkinsus marinus and MSX. We also describe our current view of population structure in Crassostrea virginica, and how it may affect the evolution of disease resistance. Finally, we explore approaches to the development of disease-resistant oysters that capitalize on the g eneric variability inherent in C. virginica and within the genus Crass ostrea.