Dr. David Liu led a study that led to the development of a new genetic editing technique, even more precise than Crispr-Cas9. Prime editing - that's the name - offers greater control and reduces the risk of unwanted changes. It could therefore open the door to new applications, today only theoretical in order to avoid unexpected changes in the DNA.
The new tool may fail to handle large changes like those of Crispr-Cas9. For the moment, therefore, it is unlikely to replace it in its entirety. This is because first editing encodes the changes on an RNA strand. The longer the filament stretches, the more likely it is to be ruined during the operation. On the other hand, the process is much more versatile than the old genetic editing technique.
Both Crispr-Cas9 and prime editing cut DNA at specific points in the genome. Crispr-Cas9 breaks both strands of the DNA double helix, after which it leaves the cell itself to repair the damage. This involves greater risks, since the healing process does not always go as planned. Prime editing bypasses these problems and reduces risks. The new technique uses Cas9 to recognize DNA sequences, but acts on a single strand of the helix. Then a second enzyme intervenes, guided by an RNA filament, which repairs the damage done by the cut. All this allows to act in a less invasive way and makes DNA healing better controllable.