It has been nearly 30 years since the gene-editing tool, CRISPR/Cas9 was discovered, and only six since it was used for the first time in human cells. Of course, its potential was not appreciated when it was discovered, as it was merely another form of a bacterial immune system. While its use in humans and agriculture has sparked controversial debate in recent years, there is no room to overlook CRISPR’s potential to do good. In the past 6 years, the CRISPR system has undergone refinement to ensure specificity and precision. It is not a perfect system, but it is certainly headed in that direction.
Last month, a new variant of the CRISPR model was introduced. Prime editing, although unable to edit the larger sections of DNA like CRISPR/Cas9, is far superior in terms of precision as it allows for fewer mishaps in the process of removing and replacing DNA segments. This is achieved by lengthening the editing process. Unlike the original CRISPR/Cas9 model, prime editing attempts to convey edits in a 3-step process, as opposed to a single step.
Another team from Columbia University cited the successful development of a further refined CRISPR technique by attaching CRISPR to parts of DNA called transposons which allows for cleaner insertion of DNA segments. Transposons (or ‘jumping genes’) are sequences of DNA which can change their position within the genome, making it easier to edit without producing dreaded ‘off-target effects’.
Amazingly, amidst all of the updates to the CRISPR system, we are also starting to see tangible results in clinical trials. For example, the University of Pennsylvania is currently using CRISPR/Cas9 as a means of immunotherapy for terminal cancer patients. The excitement over the CRISPR/Cas9 gene-editing tool has far from fizzled out, and there is no doubt that further developments and applications will be discovered in the months and years to come.
Vanessa Gomes – Science Writer