If you are asking, “What is CRISPR?” the short answer is it’s a molecular tool able to target and cut genetic material. CRISPR technology is a big-ticket news item these days. CRISPR gene editing is also controversial, which is why so many people are talking about it.
There is a lot of media hype about this form of genome editing. The science is moving faster than the regulatory bodies in the world can govern it.
People must understand how this technology works and what having it might mean. Consider some things worth knowing about CRISPR gene editing.
How Does CRISPR Work?
Clustered Regularly Interspaced Palindromic Repeats (CRISPR) utilizes a Cas9 protein able to snip gene sequences and guide RNA to target the cut. It sounds very high-tech, but such systems develop spontaneously throughout the bacterial world to defend against invading viruses.
Scientists have found ways to repurpose this process to precisely alter genomes. It starts with damaging the DNA.
A double-strand break through the double helix causes the damage. Then the cellular repair mechanisms kick in, and scientists persuade those repair processes to edit based on their instructions instead of what they might typically do.
The Brilliance of the Guide RNA
The true magic of CRISPR gene editing is in this guide RNA. This is what works to target the cut. Guide RNA is straightforward to design and purchase. It is the only part that is modular about the CRISPR system. Everything else is static, which is why this is such a powerful and easy system to use.
The guide RNA and the Cas9 protein move along the genome together. Since the guide RNA has a specific target, nothing happens until it finds its match. Then, it unleashes the Cas9 protein between the two strands of that double helix. The protein snips at that point.
Making the Cut
The cut triggers the cell to act because now it has broken DNA. There is a process in place to fix damaged DNA. First, the system tries to push the two helix pieces back together. That isn’t a very efficient process, though. Some bases can fall off, or new base pieces attach so it can get messy.
The second part of the repair process works more precisely. It takes homologous or similar DNA to make the repair. In diploid organisms, which have two sets of chromosomes, like humans, the repair mechanism uses the other chromosome to make the fix.
CRISPR Gene Editing Hijacks This Natural Process
CRISPR technology uses this natural process but feeds new DNA into it. This DNA is homology on both ends but has a different sequence in the middle. In this way, it works like a Trojan Horse. By changing just one or two letters in the series, scientists can change the DNA.
CRISPR gene editing is controversial because it is a big deal to change DNA. There is still a lot they don’t know about guide RNA and how they work. There are many important questions still to ask. No one should ignore the potential of this science, though, and the vital work it can do.