Detection of Transgenic Atlantic and Coho Salmon by Real-time PCR

Abstract

Genetic modifications (GM) have been applied to salmon to generate fast-growing strains for potential use in aquaculture. In November 2015, the first transgenic salmon (AquAdvantage® Atlantic salmon) was accepted for commercialization in the USA under defined conditions. The presence of GM food products in the marketplace stimulates the need for detection methods to allow screening for the presence of genetic modifications in seafood products. This paper first shows that it is possible to obtain amplifiable DNA from raw and processed products containing salmon. Detection methods by real-time PCR are proposed in this work. An endogenous gene target was designed to detect salmonid species DNA in samples. In addition, detection methods using real-time PCR were developed for two GM salmon possessing growth hormone transgenes: the AquAdvantage® Atlantic salmon (Salmo salar) developed by AquaBounty for commercial purposes, and the coho salmon (Oncorhynchus kisutch) developed for research purposes by Fisheries and Oceans Canada. The methods are able to detect at least 20 copies of the target. It was found however that one of the construct-specific methods for the AquAdvantage® salmon detection did not work on AquAdvantage® genomic DNA even though it works on the sequence published in GenBank. The other assay however was found to reliably detect AquAdvantage® transgenic sequences in genomic DNA.