Prime Editing: What is it and What are its Possibilities
I first heard about gene editing when I was in grade 6 (2018). One of my classmates gave a presentation on how with gene editing, people can design how their babies will look like. At that time, I thought that was the limit of gene editing. But, in 2019, I did a project on examples of gene mutations in movies and how they could be replicated in real life. My partner and I took the example of Captain America. In the movie, Captain America becomes instantly taller and stronger by taking a serum. Of course, this serum does not exist in real life. So we started looking into gene editing.
Our project focussed on the CRISPR Cas-9 technique. More recently, however, there have been more and more talks about Prime editing. Initially, it was unclear to me the difference between the two methods. After research, I got the answer of my questions and I have covered that in the article later. In this article, I will cover the following topics:
- What is Prime Editing?
- How is it different from CRISPR?
- Why is it Important?
- What is the future of Prime Editing?
- Prime Editing: Is it ethical?
What Is Prime Editing
Prime Editing is a form of ‘search and replace’ gene-editing technology. But what is gene editing?
Gene editing is a way that doctors and scientists can correct or modify a DNA sequence by adding, removing or modifying the sequence. Prime editing and CRISPR are the most famous and worked on gene-editing techniques.
Prime editing uses a Cas-9 protein that is fused with an engineered reverse transcriptase enzyme. A guide RNA is used to identify the target site and provide new information to replace the target DNA nucleotide.
Like DNA, RNA is a nucleic acid and is single-stranded, however, DNA is double-stranded. In a cell, RNA is a DNA “photocopy”. RNA also has the role of regulating cell division, differentiation, ageing and death.
This technology may have the capability to modify living organisms and human cells. Prime editing has the capability of correcting 89% of DNA errors that cause genetic diseases.
How Is It Different From CRISPR?
Prime editing and CRISPR both use the CAS-9 protein but still have differences. So what is CRISPR?
CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is also a form of search and replace gene-editing technology and it also uses a CAS-9 protein. A guide RNA is used to locate the target DNA nucleotide.
CRISPR sounds very similar to prime editing. So what are the differences?
As mentioned before, CRISPR and Prime editing both rely on cutting the genome. But, CRISPR is a clumsier method then prime editing. This is because CRISPR requires that both strands of the double helix DNA be cut and relies on the cell’s auto repair function to repair the DNA. With prime editing, however, only one strand of the double helix is cut and we are able to insert the new genetic information rather than having to rely on the cell to fix it by itself. Relying on the cell may cause unwanted edits and may cause variation between cells. By inserting the information ourselves through prime editing, there is a lower risk of having by-products.
Why is Prime Editing Important?
In Canada, cancer is the leading cause of death and accounted for 30% of all deaths in Canada in 2016. In 2020, it is predicted that there will be 225,800 new cancer cases and 83,300 cancer deaths according to the Canadian Cancer Society. Although there have been many breakthroughs, there is no cure for cancer.
Did you know that there are over 75,000 DNA changes associated with genetic diseases? Prime editing has the potential of repairing mutations that cause around 7000 inherited genetic diseases (cancer included), which ultimately will save millions of lives.
It also has the possibility of curing hereditary diseases such as diabetes and cystic fibrosis. This means curing one person may avoid his or her kids from getting these diseases.
Another possibility of Prime editing is to extend human life. Throughout history, we have seen the human lifespan has increased and we are living longer and longer lives. But with longer lives, there are diseases that we establish at the later stage of our lives. Through gene editing, we can eliminate these diseases and thus, live longer and healthier lives.
What Does The Future Hold for Prime Editing
Prime editing will have a radical effect on medical sciences. However, prime editing and gene editing are still in the early stages and there still needs to be many trials to make prime editing safe and effective.
Prime editing is an advanced technique that still needs to be worked on and needs to be scalable and more available to the public at large, as it has the ability to impact millions of lives.
Prime Editing: Ethics
Nature: One ethical argument is that humans are born natural and diseases are natural and that if we as humans alter the human body to lengthen their lifespan, we are controlling when they die. And are we interfering in the act of God?
Safety: There are many safety concerns regarding prime editing including by-products and variation between cells. Although, the current regulation is that until gene editing is not considered safe, it shall not be used.
Uses other than disease treatment: Many people also believe that gene editing will soon evolve from a life-saving technique into a human enhancement procedure. Human enhancement is a highly controversial topic. The argument for this is that gene editing should be controlled through laws and that it should only be allowed to treat genetic diseases and disorders.
Future Generations: There is also the concern that gene editing will be done without the consent of future generations as it will also be affecting them. But, there are already other medical procedures that are performed that has an effect on future children.
Inequality: With gene editing being an advanced and highly technical procedure, it is safe to say it will be very expensive when it is made available. The concern is that only people in higher social classes will have access to gene editing and that in the future there will be classes that are identified by the quality of their genome. This will further increase the gap between lower and higher social classes.
There are a lot of concerns regarding the ethics of gene editing. However, gene editing has the potential to save millions of lives if used in the right ethical manner. But, I believe there needs to be a lot of work done regarding regulations and ethics before this technology is released to the public.
In this article, I covered what prime editing is, why it is important, how it is different from CRISPR, what the future is for Prime Editing and the ethics of gene editing.
Begley, S., Begley, S., Begley, S., Begley, S., Herter, R., Klein, R., … Terri RN BSN. (2019, October 21). New CRISPR tool could fix almost all disease-causing DNA glitches. Retrieved from https://www.statnews.com/2019/10/21/new-crispr-tool-has-potential-to-correct-most-disease-causing-dna-glitches/
Cancer statistics at a glance — Canadian Cancer Society. (n.d.). Retrieved from https://www.cancer.ca/en/cancer-information/cancer-101/cancer-statistics-at-a-glance/?region=on#:~:text=There will be an estimated,for 30% of all deaths.
Ledford, H. (2019, October 21). Super-precise new CRISPR tool could tackle a plethora of genetic diseases. Retrieved from https://www.nature.com/articles/d41586-019-03164-5#:~:text=CRISPR–Cas9 and prime editing,specific point in the genome.&text=Although it also uses Cas9,nick only one DNA strand.
Thulin, L. (2019, October 21). A New Gene Editing Tool Could Make CRISPR More Precise. Retrieved from https://www.smithsonianmag.com/science-nature/prime-editing-new-form-crispr-technology-make-gene-editing-more-precisie-180973381/
What are the Ethical Concerns of Genome Editing? (n.d.). Retrieved June 15, 2020, from https://www.genome.gov/about-genomics/policy-issues/Genome-Editing/ethical-concerns