The potential for large-scale genome editing in finfish aquaculture via germline stem cell culture and transplantation

Genome editing has emerged as a promising tool to complement selective breeding programmes and accelerate genetic gain in aquaculture. Although CRISPR-based genome editing has been successfully applied in several economically important fish species, its application at an industry-relevant scale remains challenging due to limitations of current delivery methods, which primarily rely on manual embryo microinjection. This approach is labour-intensive, technically demanding, and frequently results in high levels of mosaicism in founder individuals, necessitating additional generations of breeding to establish stable genotypes. In this mini review, we discuss the potential of combining germline stem cell (GSC) culture and transplantation approaches as an alternative platform for further improved genome editing in fish. By enabling genetic changes to be introduced, validated, and expanded in vitro prior to germline transmission, this approach has the potential to improve scalability, reduce mosaicism, and shorten breeding timelines. Although several technical challenges remain, continued progress in GSC culture and transplantation methodologies could facilitate the practical implementation of tailored genome editing for improved genetic gain, fish health, and welfare in aquaculture.