Which of the following is a common method of gene editing?

The correct choice highlights CRISPR-Cas9 technology as a common method of gene editing due to its precision and efficiency. This revolutionary technique allows scientists to make specific changes to the DNA of organisms by utilizing a guided RNA sequence to direct the Cas9 enzyme to a desired location in the genome. Once there, Cas9 can create a break in the DNA, enabling the addition, deletion, or alteration of genetic material.

CRISPR-Cas9 stands out in the field of genetics because it is relatively straightforward to design and implement, making it accessible for researchers in a variety of biological fields. Its applications range from creating genetically modified organisms to developing new treatments for genetic disorders. The ease and versatility of CRISPR have contributed to its rapid adoption and recognition as one of the leading methods in gene editing today.

Other methods listed, while significant in biotechnology and genetics, serve different purposes or operate on different principles. Gene therapy involves using viruses to deliver new genes into cells, RNA interference is a mechanism for regulating gene expression rather than editing, and transgenic organisms involve the incorporation of genes from one species into another but are not a method of editing existing genes within an organism's genome.