Tol2-mediated transgenesis in tilapia (Oreochromis niloticus).

The Nile tilapia (Oreochromis niloticus) is an important species in aquaculture and an excellent model system for laboratory studies. Functional genetic analysis using this species has been difficult because existing methods for producing transgenics are inefficient. Here we show that the Tol2 transposon system can be used to create transgenic tilapia with high efficiency. We constructed a line that is transgenic for GFP under control of a Xenopus elongation factor 1α (EF1α) promoter. The germline transmission rate of the Tol2 construct to the first generation was about 30%, which is much higher than conventional methods. GFP expression was strong and ubiquitous in the embryos. Application of the Tol2 system for constructing transgenics in tilapia and related species will promote research in many areas, but will be especially useful for studies of evolutionary developmental biology in the cichlid fishes of East Africa.