Year‐round spawning increases throughput of genetic modification of common carp ( Cyprinus carpio )
Julie Badger, Nicholas K. Jacob, Colby Johnson, Leland Feist, Samuel E. Erickson, Isabel Ameli, Dimitri Perusse, Alex W. Bajcz, Kieran Smith, Kaitlin Machina, Siba R. Das, Przemyslaw G. Bajer, Michael J. SmanskiAbstract
The common carp ( Cyprinus carpio ) is an economically and ecologically significant species. It is both one of the most highly produced fish in aquaculture globally and a persistent, widespread invasive species. Research efforts focused on understanding its biology, improving traits for aquaculture, and generating next‐generation carp control technologies, all of which benefit from reliable and robust protocols for spawning and genetic transformation. Here, we report a retrospective analysis of carp husbandry and spawning experiments to identify key parameters influencing the successful production of viable embryos in laboratory settings. Next, we produced brightly fluorescent transgenic common carp using the Tol2 transposase system to deliver DNA encoding a fluorescent reporter and demonstrated the transgene was heritable. We also attempted to optimize other protocols related to the production of genetically modified common carp, such as finding the ideal cryoprotectant exposure time for sperm cryopreservation, testing egg de‐adhesion solutions, and identifying conditions affecting storage time of unfertilized eggs and sperm. Lastly, we demonstrated how a fluorescent reporter construct could be used to select for gene‐edited carp at multiple stages of development. Together, this work demonstrates how optimization of many parts of the genetic modification process can greatly enhance its efficiency.