Characterization of Gonadal Differentiation and Isolation of Factors Involved in Reproductive Development in Marine Bivalves
Research Proposal (non-funded) submitted to USDA. Includes reviewer comments.
Summary
The long term goal of the research proposed by the PD is to characterize the reproductive biology in marine bivalves, concentrating particularly on aspects that could be used to develop novel approaches to induce sterility. The specific objectives of the research proposed here are to: 1) characterize gonad differentiation in juvenile bivalves and 2) isolate factors involved in gametogenesis in adult bivalves. To complete the first objective two approaches will be taken. First, a histological and in situ analysis approach will be used to characterize migration of germ cells and development of early gametes. Specifically, conventional histological techniques will be combined with cellular localization of vasa, a germ cell specific marker, in juvenile oysters and scallops. The second approach will be to use Expressed Sequence Tag (EST) analysis to identify transcripts expressed during early gonad differentiation. In order to isolate factors involved in gametogenesis, two approaches will be taken. A reverse transcription polymerase chain reaction (RT-PCR) approach to isolate candidate genes based on sequence homology will be used. Targeted genes for RT-PCR include Gonadotropin Releasing Hormone (GnRH) neuropeptide and aromatase, a key enzyme in sex steroid metabolism. In addition, EST analysis will be used to identify transcripts expressed in the ganglia of clams and gonads of oysters during gametogenesis. Upon completion of these objectives, 1) information will be provided on appropriate times to manipulate sex in bivalves and 2) reproductive factors will be elucidated that could eventually be used at targets to induce sterility in bivalves.
