Blog 6: CRISPR
Hello again! Sorry for the wait but this topic is so huge for synthetic biology that it took me a little longer to compress it down into a blog. Winning the 2020 Nobel Prize in chemistry, CRISPR is one of the most crucial innovations to genome editing and will only continue to improve.
Today I’ll be covering CRISPR: what it is, how it works, and how it’s already shaping our world today.
What is CRISPR and How it Works
You’ve probably already heard of CRISPR at some point in your life, but did you know it actually comes straight from nature?
Originally, CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) was discovered as part of a natural defense system that bacteria used to fight off viruses. When a bacteria survives a viral attack, they keep a tiny piece of the virus’s DNA as a memory. Because of this, if the same virus was to attack again, the bacteria can recognize and destroy it faster. My mom calls it a “natural immunity” and I saw it during COVID-19 where I was able to go around stress-free a week or two after having covid.
Anyway, scientists realized that this system of virus-holding could be turned into a powerful gene-editing tool and that’s exactly what they did. However, instead of directly fighting viruses, they could program CRISPR to find and edit specific pieces of DNA in plants, animals, and even humans.
The tool that allows for CRISPR to work is actually called CRISPR-Cas9. Cas9 is a special protein that acts like a pair of “molecular scissors”. Using RNA as a guide, Cas9 is able to find the exact spot in the DNA that the scientists want to cut and make a snip. Once this happens, the cell’s natural repair system jumps in and gives scientists the opportunity to tweak, delete, or even insert brand new DNA in the location of the snip.
Real World Applications of CRISPR
Now that I’ve explained what CRISPR is and how it works, let me show you how it's affecting our world today.
One of the biggest hopes for CRISPR is that it will be able to cure genetic diseases. Today, it has already begun to treat blood disorders like sickle cell anemia and beta-thalassemia by fixing a single “genetic typo”. I’d like to mention here that in 2023, the first CRISPR-based therapy for sickle cell disease was approved in the United Kingdom, which was then approved by the U.S shortly after.
Using CRISPR, scientists are also able to strengthen the immune system against cancer. To do so, scientists have to take a patient’s T-cells (a type of immune cell), use CRISPR to reprogram them to better recognize the tumors, and then infuse the cells back into the person they are trying to help.
Beyond cancer, CRISPR is being used to cure and eliminate malaria. In this case, scientists are trying to eradicate it by editing the genes in mosquitoes. If they are able to spread genetic changes that make mosquitoes infertile or prevent them from carrying malaria at all, it could cure a disease that has caused detrimental damages for so long.
Getting away from disease control and cures, CRISPR is also being put towards agriculture and has already gone a long way at transforming typical farming practices. Researchers have found a way to use it to make crops more nutritious, more drought-tolerant, and even more disease resistant. For example, wheat has been edited so that it can be more resistant to mildew. Possibly even bigger, tomatoes have also been edited to produce more GABA, a nutrient that could help lower people’s blood pressure.
And last of this list of examples would be how CRISPR is being put forward to engineer livestock and different animals. Specifically, animals are being edited to be healthier and more productive. For instance, CRISPR is being used to breed pigs that are resistant to deadly viruses like PRRS (porcine reproductive and respiratory syndrome). Here, it’s being used to boost the pork industry and protect the population of pigs.
While those are most of the examples I’ve found online, I would like to mention that CRISPR has only been utilized for 10 years and continues to make a bigger impact each and every day. Even in a year, I can guarantee you this technology has improved another process or organism in some way that benefits the world around us. That’s just how powerful this technology is.
The Risks and Limitations that Come with CRISPR
Even though all of the current things it's doing may seem like a really good thing, it's still important that you realize that this technology isn’t perfect yet. Now that I’ve named most of the positives of CRISPR, let me get into some of the challenges and ethical questions revolving around the matter.
One of the biggest issues with this technology is its accuracy. Even though CRISPR is much more precise than the older gene-editing methods, it can still have mistakes called off-target effects where the technology reads the wrong part of the DNA. Unfortunately, even a small mistake could cause big problems. For example, if CRISPR were to go in and disrupt a healthy gene, it could trigger a new, unwanted disease such as cancer or another genetic disorder that wasn’t wanted.
Because of these potential risks, many countries have banned the process of germline editing (changes being passed down through generations). Other countries are still trying to figure out what their rules should be.
Potentially a bigger concern would be the ethics of this technology. Right now, most of the issues come from the ability to control human traits like height, intelligence, or athleticism. The action of editing human embryos is referred to as “designer babies” and brings up a lot of questions about fairness, consent, and the definition of human.
Conclusion
And that about ends it for my segment on CRISPR. I hope I was able to summarize both the pros and cons of this technology to better your understanding.
To summarize, CRISPR is a newer idea in the field of synthetic biology and involves using CRISPR-Cas9 to snip and modify segments of DNA.
Thank you all for reading, until next time.
- Aidan Kincaid
Some of the Resources I Used + Additional Articles:
1) Stanford’s “What is CRISPR”
2) Undark’s Article on how CRISPR is Changing the World
3) CRISPR in Cancer Research
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