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GENOME EDITING

For decades, people have been yearning for being able to permanently alter the DNA, by inserting or deleting genes or specific pieces of DNA. The reason is that this process can be applied to agronomy, veterinary and human medicine.

Some tools that are currently used to modify DNA are Zinc finger nucleases (ZFNs), transcription-activator like effector nucleases (TALEN), and the revolutionary technique of nucleases and the clustered regularly interspaced short palindromic repeats (CRISPR/Cas) system.

The first two, are based on proteins conformed by a DNA catalytic domain and a recognition domain of the targeted gene. It is not possible to make multiple changes simultaneously with the first two techniques. However, with the CRISPR/Cas technique, it is possible to modify a DNA sequence easily, quickly and accurately in different domains of the genome of a living organism. This genome editing technique is inspired by the rudimentary immune system with which some bacteria keep virus genome fragments in their genome. This process allows the bacteria to identify the virus and produce enzymes that cut and deactivate the RNA virus.

The CRISPR-Cas technique has already been used to cause and correct mutations in different types of cells, including bacteria and human eukaryotic cells. However, its main inconvenient is the involuntary generation of genetic material errors. This situation decreases the efficacy of the technique, preventing it to be considered as a future gene replacement therapy.