Harnessing CRISPR/Cas9 system to improve economic traits in aquaculture species.

Clustered regularly interspaced short palindromic repeats associated with Cas9 (CRISPR/Cas9) system is a powerful and efficient tool for molecular modification in the genome using programable RNAs. It holds a wide application in plant and animal biotechnology for enhancing multiple traits of interest. Here, we attempted to gather and review the recent progress and provide an overview of the application benefits of this technology in aquatic animal genomes. In this respect, several studies were performed on different species (marine and freshwater) investigating the growth bioprocess trait, wherein, the majority of them focused on somatic axis suppressors such as mstn (myostatin) knock-outs and their effects on the differentiation and proliferation of somatic cells. Regarding the reproduction feature, the retrieved studies provide insights into germ cells, sex reversal, and fertility mechanisms with more focus on zebrafish and tilapia compared to other species. In turn, a generation of de novo strains more resistant to viral infections has been successfully attended to proving the practical ability of this technology in enhancing the immunity of certain species such as grass carp. Furthermore, multiple experiments were performed to explore the pigmentation particularity and understand the melanin biosynthesis pathway via tyr (tyrosinase) gene knock-out in different freshwater species. To investigate the metabolism processes, researchers attempted to grasp the molecular mechanisms underlying polyunsaturated fatty acids biosynthesis and lipid metabolism in Atlantic salmon and channel catfish. In another aspect, earlier studies were undertaken in cyprinids to produce intramuscular bone-free populations as an important trait of interest. Finally, we examined the possible challenges and perspectives for the future use of this technology in the research field. Overall, the application of CRISPR/Cas9 system is an effective approach to manipulating target genes and enhancing economic traits in different aquatic animal species, thereby strengthening genetic breeding programs. • Inducing mutagenesis to enhance different biological traits via CRISPR/Cas9. • Microinjection is the main used technique for CRISPR/Cas9 delivery. • Challenges and perspectives for the future use of this editing tool in the research field. [ABSTRACT FROM AUTHOR]