CRISPR-Cas9 is a genome editing tool that enables geneticists and medical researchers to edit parts of the genome by removing, adding, or altering sections of DNA. It is a family of DNA sequences found in the genomes of prokaryotic organisms such as bacteria and archaea, which are derived from DNA fragments of bacteriophages that had previously infected the prokaryote. The CRISPR-Cas9 system has generated a lot of excitement in the scientific community because it is faster, cheaper, more accurate, and more efficient than other genome editing methods.

The CRISPR-Cas9 system consists of two key components: the Cas9 enzyme and a guide RNA molecule. The guide RNA molecule is designed to recognize and bind to a specific sequence of DNA, while the Cas9 enzyme cuts the DNA at the targeted location. This allows researchers to edit genes within organisms, which has a wide variety of applications including basic biological research, development of biotechnological products, and treatment of diseases.

CRISPR-Cas9 has a lot of potential as a tool for treating a range of medical conditions that have a genetic component, including cancer, hepatitis B, or even high cholesterol. However, much research is still focusing on its use in animal models or isolated human cells, with the aim to eventually use the technology to routinely treat diseases in humans. There are clinical applications in human trials now, including for engineering T cells outside of the body for CAR-T cancer therapy and for editing retinal cells for Leber’s congenital amaurosis 10, an inherited form of blindness.

It is important to note that CRISPR-Cas9 is an extremely powerful tool, but it has important limitations. It is:

• Not 100% accurate and can sometimes cut DNA at unintended locations.
• Limited by the size of the DNA sequence it can edit.
• Not yet fully understood, and there is still much research needed to fully understand its potential and limitations.