CRISPR for Genome Editing

Genome editing is the combination of technologies that allow scientists to alter an organism's DNA. Through these technologies, the genetic material could be added, changed, and removed at a particular genome location. Multiple approaches were taken to edit the genome, among which is CRISPR-Cas9. The CRISPR-Cas9 system has generated tremendous excitement in the scientific community as it is faster, more accurate, cheaper, and more efficient than other genome editing methods. CRISPR gene editing is the genetic engineering technique through which the genomes of living organisms can be modified. Hence these techniques are based on the simplified version of bacterial CRISPR-Cas9 antiviral defense systems.

CRISPR-Cas9 Technique

The CRISPR-Cas9 technique was adapted by the naturally occurring genome editing systems used as an immune defense. When the virus infects Bacteria, Bacteria can capture small pieces of the viruses and insert them into their own DNA to create segments termed CRISPR arrays. These arrays allow the bacteria to memorize the viruses. Hence whenever the virus attacks back, the bacteria would generate RNA segments from the CRISPR arrays by attaching them to the specific regions of the viral DNA. This step is followed by using Cas9 or a similar enzyme to cut DNA apart, disabling the virus and altering the viral genome to get any further processed.

Working on Genome Editing through CRISPR

This technology was of great interest to the scientists, who adapted it as an immune defense to edit DNA. Small fragments of RNA with short guide sequences bind to specific target DNA sequences as bacteria produce from CRISPR array. The guide RNA can recognize the targeted DNA sequence, followed by the Cas9 enzyme, which cuts the DNA at the targeted location and mirrors the process in bacteria. Following the incise of DNA, scientists utilize the cell's DNA repair machinery to insert or delete the pieces of genetic material to alter DNA by editing the existing segment with customized DNA sequences.     

Applications of Genome Editing

Genome editing is of great interest in preventing and treating human diseases. To Date, genome editing is utilized in cells and animal models in research labs to observe conditions. Scientists are still busy observing to determine these approaches as safe and effective for commercial use. Genome editing through CRISPR-Cas9 has been explored in research and clinical trials for various applications, particularly on the clinical side, including single-gene disorders like hemophilia, cystic fibrosis, and sickle cell disease. Moreover, it also holds an essential step for treating and preventing more complex diseases like heart disease, mental illness, cancer, and human immunodeficiency virus infections.

Ethical Concerns

Ethical concerns were raised through genome editing technology, mainly through using CRISPR-Cas9 to alter the human genome. In that regard, most changes are limited to somatic cells, isolated to only specific tissues, and not passed from one generation to another. Based on the raised concerns on the ethics and safety of the genome editing of germline cells and embryo genome editing, it is currently illegal in the United States and many other countries.