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Add To Calendar 24/02/2016 14:00:0024/02/2016 14:20:00America/ChicagoAquaculture 2016A novel approach to genetic-containment: producing sterile fish by disrupting primordial germ cell development Vendome BThe World Aquaculture Societyjohnc@was.orgfalseanrl65yqlzh3g1q0dme13067DD/MM/YYYY

A novel approach to genetic-containment: producing sterile fish by disrupting primordial germ cell development

Wong, Ten-Tsao and Zohar Yonathan
Department of Marine Biotechnology & Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Maryland, USA. Email: twong@umbc.edu

 

Aquaculture is progressively becoming more prevalent and increasingly vital to resolve the shortages in aquatic food availability. One approach to increasing aquaculture production is through the use of genetically modified (GM) fish that exhibit enhanced performance, such as good growth characteristics and/or disease resistance. Maximization of production will also require environmentally sustainable aquaculture approaches to minimize ecological impact. It is imperative that highly effective containment methods are available to prevent escaped GM fish from propagation in the natural environment. To tackle this issue, we have developed a novel bath-immersion technology to produce infertile fish. Farming infertile fish is the most effective genetic-containment strategy to support the development of environmentally-responsible aquaculture. The technology was used to identify compounds that effectively caused primordial germ cell (PGC) mis-migration and differentiation into somatic cells, which resulted in generation of sterile fish. Optimal embryo survival and disruption of PGC migration was achieved to induce 100% sterility even when the total immersion time was reduced from 24 to 5 hours in zebrafish. In 8 independent experiments, 736 adult zebrafish developed from these conditions were all found to be infertile fish that possessed minimally-developed gonads that lacked any gametes. Pilot trials showed that our sterilization technology can also be used to induce sterility in rainbow trout and the work to optimize immersion conditions is ongoing. Studies towards the application of this sterilization concept in Atlantic salmon and tilapia are also underway.

PGCs are a population of cells in the embryo that give rise to the eggs and sperm of the adult. In fish, PGCs are specified during early development by the incorporation of maternally-derived germ plasm and then migrate to the developing gonad. We established a bath-immersion method to identify compounds that are able to disrupt PGC development and eventually result in failure of gonadal development and sterility (Fig. 1). To better visualize PGCs, a transgenic zebrafish, Tg(kop:DsRed-nanos3), that expresses DsRed driven by the PGC-specific kop promoter and nanos3 3'UTR was used for this study. Since the development of PGCs and gonads within the embryo is an evolutionarily conserved mechanism in fish, it is expected that the technology can be successfully applied to other fish including a wide variety of aquaculture species. The success of our approach potentially provides an inducible method to generate reproductively sterile fish for aquaculture. Additionally, the use of bath immersion makes it convenient to maintain a fertile broodstock population by simply omitting the treatment of the embryos. Our technology can thus be used for genetic-containment and cost-effective aquaculture operations, which will contribute to the development of environmentally and economically sustainable production to meet the growing global demand for seafood.




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