CRISPR is a family of DNA sequences found within the genome of prokaryotic organisms such as bacteria and archaea; these sequences are derived from DNA fragments of bacteriophages that had previously infected the prokaryote. They are used to destroy DNA from similar bacteriophages during subsequent infections. And quite recently the discovery of the CRISPR-cas9 gene editing tool has brung us a revolutionary change for the treatment of genetic disorders. These may include, but are not limited to muscular dystrophy, thalassemia, and hemochromatosis. Additionally, potential candidates of this treatment may include those with blood disorders, AIDS, cystic fibrosis and blindness.
With the newfound ability to alter DNA sequences, cancer is also being looked into by researchers, with current trials focusing on the treatment’s effectiveness continuing. Recent trials studying sickle cell anemia and beta thalassemia have actually been a success. It’s likely that CRISPR based technology could be a new era of transformative medicine that could soon be approved.
(Top biotechnology developments for 2023, n.d.)
It’s quite impressive what genome editing can do for the medical industry. Scientists are now able to quickly create cell and animal models and researchers can use these to accelerate research into diseases like cancer and mental illness. Feng Zhang and his team are also encouraging this form of research, training thousands of researchers in the use of CRISPR genome editing technology through over 40,000 CRISPR components with academic laboratories across the world.
CRISPR-cas9 is not the only genome editing tool. But, it is proving to be efficient and a great alternative to other existing tools out there. Since the CRISPR-cas9 system itself is capable of cutting DNA strands, they do not need to be paired with separate enzymes as other tools do. They can also be matched with tailor-made RNA (gRNA) sequences designed to lead them to their DNA targets. In fact, tens of thousands gRNA sequences have been created and are available to the research community. But a major difference between CRISPR-cas9 is that it can target multiple genes simultaneously, which is another advantage that sets it apart from others. (Questions and answers about CRISPR, 2014)
Unfortunately, though, like almost all other discoveries, CRISPR-cas9 also seems to pose some risk on human embryos. Gene editing is currently used in children and adults with diseases caused by gene mutations as mentioned earlier. And many inherited disorders can also be avoided by carrying out gene editing on human embryos before they implant in the uterus; this is the only stage of development when CRISPR-cas9 technology can reliably reach every cell of the embryo.
Dr. Kubikova and her colleagues conducted an experiment and ultimately, Dr. Kubikova detected alterations at the targeted DNA sites, indicating that this technology is highly efficient in the cells of human embryos. However, just 9% of targeted sites were repaired using the clinically useful process of “homology directed repair” (the process of repairing a break in DNA.) 40% of broken DNA strands failed to be repaired at all leading to large pieces of chromosome being lost or duplicated. Babies resulting from such embryos, would carry a risk of congenital abnormalities. The majority of cells repaired the DNA break, using non-homologous joining, resulting in additional mutations, rather than correcting the existing ones. But before things can become great, there’s always some flaws and even Dr. Kubikova says the outlook isn’t all negative. She says: “While the results caution against the use of genome editing in human embryos, there were some positive findings, suggesting that risks can be lowered and the ability to successfully remove mutations can be increased by modifying the way in which genome editing is undertaken. This offers hope for future improvements to the technology.” (Cooke, 2023)
So what do you think? Could CRISPR-cas9 technology offer revolutionary changes to the field of medicine?
— Written by Joya
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