The answer to the question about the name of the protein that could be used to modify or edit the genes for genetic modification of fish is letter A or CRISPR Cas9. Before we delve into this kind of protein, CRISPR stands for Clustered regularly-interspaced short palindromic repeats which are segments of the prokaryotic DNA that contains short repetitions of all base sequences.
These sequences are used in a bacterial defense system and the technology of gnome editing called CRISPR Cas9 – the Cas9 stands for CRISPR-associated protein-9 nuclease. The CRISPR Cas9 helps cleaves foreign DNA which contains a 20-nucleotide crRNA (CRISPR RNA) complementary sequence. RNA stands for ribonucleic acid which is an acid that is present in all living cells.