Plant & Animal Genomes XVI Conference Plant & Animal Genomes XVI ConferenceJanuary 12-16, 2008
Town & Country Convention Center
San Diego, CA
Melony J Sellars1,2 , Peter M Grewe3 , Nigel P Preston1,2
Selective breeding of elite genotypes is playing in increasingly important role in the success of the global shrimp farming industry which has an annual production value of US$ 8 billion. The success of shrimp breeding programs has prompted the search for fail-proof techniques to prevent unwanted or unlicensed breeding of elite genotypes. Because female shrimp grow larger than males there is parallel interest in producing all female stocks which could improve pond yields by up to 30%. Despite significant global research investment over the last decade, a technique that can provide fail-proof genetic protection and the production of 100% female populations is yet to be developed.
Silencing the expression of genes pivotal to fertility and gender determination during early embryo and larval development through the RNAi pathway is one alternative approach that could result in sterile all-female shrimp. We have successfully isolated several genes from the Kuruma shrimp such as doublesex that are known to be pivotal to gender and fertility determination in other invertebrate species. Expression profiles of these genes have been determined throughout embryonic, larval and postlarval development to identify the critical time point when to be silencing gene expression to result in loss-of-function genotypes. Recombinant vectors with the WSSV IE1 promoter driving expression of shRNAs have been constructed for each of the isolated genes and their ability to fold and initiate a specific gene silencing response demonstrated in cell culture. These recombinant vectors were delivered into 1-cell embryos and the reduction in target transcript abundance quantified.