The article reports on the versatility of Cas9-based system in the modification of genomes of living organisms, and human and murine cell lines. It references the studies conducted by researchers including one by M. Jinek and colleagues on the replacement of two short ribonucleic acids (RNAs), another by P. Mali and colleagues on HIV co-receptor CCR5, and one by W. Y. Hwang and colleagues on alteration of genes in zebrafish. It adds data on the formation of RNA-guided endonuclease (RGEN).