CRISPR — the cost, concerns, and future of genome editing
CRISPR is a genome editing tool that revolutionized the scientific community and has been all over the news for the past few years. It is much faster, cheaper, and more accurate than other existing DNA editing techniques.
This technique has a wide variety of applications that go well beyond human health. However, regardless of its importance and utility, there are still some causes for ethical concerns when using CRISPR for genome editing.
In this article, we’ll go over the CRISPR technique to better understand how it works and why it’s so important. We’ll also cover both common and unusual CRISPR applications, the high costs of CRISPR-based treatments, and what’s in the future for this genome editing technique.
What is CRISPR?
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. It’s a component of bacterial immune systems that can cut specific DNA strands as if it were a pair of precise molecular scissors.
This system was discovered because scientists observed situations in which bacteria were being infected by viruses. CRISPR was able to cut the bacteriophage’s DNA and therefore disable it, preventing the infection.
It has been repurposed as a genome editing tool as it allows scientists to remove, add, or alter specific sections of the DNA sequence. It is also considered the most simple and versatile method of genetic manipulation in the scientific community.
How does CRISPR Work?
The CRISPR system is composed of two parts:
- CRISPR-associated (Cas) nuclease. Binds and cuts the specific strand of DNA.
- Guide RNA sequence (gRNA). Leads the Cas nuclease to the target DNA.
During viral infection, the Cas nuclease snips off a piece of the viral DNA, called a protospacer. This piece is stored within the bacterial genome along with other fragments gathered from previous viral infections, thus creating a sort of immune memory. These viral protospacers are organized together between repeated palindromic sequences, creating spacers. This is what gives CRISPR its name.
If that same virus tries to reinfect the bacteria, it will be able to recognize the viral DNA and destroy it with Cas9. The activity of this nuclease depends on a gRNA, the nucleic acid strand that will guide Cas9 to the place where it should cut. But how does the recognition happen?
The Cas9 searches for something called the protospacer adjacent motif (PAM), a short sequence located downstream of the target site. Once it locates the PAM, it will then look upstream to find the target provided by the gRNA. When Cas9 finds it, it cuts the viral DNA incapacitating it.
Common CRISPR Applications
CRISPR technology has been a major player in breakthroughs in medicine and biotechnology over the past few years. It also started spreading across other scientific industries and is now being used for a multitude of purposes.
Cell and Gene Therapies
The first application that came to mind when discovering the CRISPR-Cas9 system was the creation of new cell and gene therapies, where researchers could potentially cure a range of genetic diseases.
Neurodegenerative diseases, blood disorders, cancer, and ocular afflictions are only a few examples of different conditions that could benefit from this type of technology. Recently, a few trials have been performed in actual patients, revealing promising results.
So far, in these trials, researchers were able to cure patients with sickle cell disease and showed encouraging results with a neurodegenerative disease called transthyretin amyloidosis.
Diagnostics
Half of all disease-inducing mutations in humans are caused by single nucleotide polymorphisms (SNPs). Taking this into consideration, in 2021, researchers created a tiny chip that contained graphene, transistors, and CRISPR. This chip can detect pathogenic SNPs in patients, which is a significant breakthrough in medical diagnostics.
However, CRISPR’s purpose in the diagnostics field was brought to the forefront of investigative research during the Covid-19 pandemic. Laboratory test kits were developed using CRISPR by many different companies, resulting in new diagnostic methods like SHERLOCK, STOPCovid, and DETECTR.
Agriculture
Using genome editing techniques in agriculture makes complete sense. It can be used to create disease and drought-resistant crops, prolong the shelf-life of perishable foods, reduce food waste, and allow access to a wider variety of healthy foods at lower costs.
We will likely see a higher availability of different foods and produce modified by CRISPR-Cas9 technology within five to ten years.
Bioenergy
The race to find sustainable alternatives to fossil fuels has been going on for a long time, and bioenergy is a strong contender. Using CRISPR systems, researchers have been able to make significant advances in this field.
For instance, by knocking out a few factors involved in the regulation of lipid production in algae scientists managed to increase overall lipid production, a product that can be used to generate biodiesel.
Gene editing can also help the host (bacteria, yeasts, and others) become more tolerant to the harsh conditions that occur during the production of such components. It has also improved the ethanol production efficiency in different bacterial species.
A few other emerging CRISPR-Cas9 applications include stem cells and organoids, primary cells, and CRISPR animal models.
A Few Unusual CRISPR Applications
While some applications for CRISPR might seem quite obvious, albeit revolutionary, others might be quite unusual, or at least not that obvious to the common folk.
Pet Breeding
The origins of pet breeding go back to the moment when dogs were domesticated, at least 15,000 years ago. While most people think that there isn’t much to pet breeding, they couldn’t be more wrong.
People in the pet breeding industry are always trying to keep up with the latest technologies that could potentially help our beloved companions. CRISPR could be useful in this industry in many ways.
Gene editing could be used to remove genetic diseases associated with different dog breeds, for example. Other projects for CRISPR could include creating animals with different custom sizes, colors, and patterns.
DNA “Tape Recorders”
A few Harvard scientists have recently created a CRISPR-based molecular tool called CAMERA. It acts as a sort of recorder of everything that goes on in the cell, throughout its lifetime. It manages to gather information on exposure to antibiotics, nutrients, viruses, and light.
This CAMERA works in both human and bacterial cells and can record multiple types of signals at the same time. This system might help determine the presence of nocive components in the cell and help determine the signals that dictate whether stem cells turn into neurons, muscle cells, or other cell types.
De-Extinction
It might seem like we’re moving onto sci-fi territory, but we’re not. Currently, scientists are working on bringing back the passenger pigeon, a previous dweller of the Norther American forests.
They’ll be introducing genes from these extinct pigeons into the genome of a relative of theirs from the modern days, the band tail pigeon. While the hybrids will breed for several generations, there is a chance of obtaining offspring with DNA that completely matches that of the passenger pigeon.
If this de-extinction succeeds, who knows which species might follow? The dodo? The Eurasian aurochs? Mammoths? We’ll just have to wait and see.
Ethical Concerns in Genome Editing by CRISPR Tech
CRISPR-Cas9 technology has undeniably contributed to the development of new methods and techniques that could revolutionize modern medicine, biotechnology, and many other fields and industries. However, it still raises difficult questions, concerns, and ethical issues that need to be discussed.
Most concerns stem from the use of CRISPR tech to alter human germline cells and embryos because it’s hard to accurately predict the results of such applications. Topics like undesirable changes in the genome, how consent is obtained, and the breeding of human species lead to serial bioethical concerns.
Ideally, to safely use CRISPR-Cas9 in sensitive areas like this, there should be worldwide legislation that takes into account the opinions of scientists, policymakers, and stakeholders. However, not everyone shares this point of view.
In 2018, a researcher in Chine revealed that he had used CRISPR-Cas9 to edit embryos that he then implanted into the mothers. The fathers in both cases were HIV-positive and therefore barred from access to assisted-reproduction technologies in China.
The Chinese researcher edited the CCR5 gene in the embryos, which encodes an HIV co-receptor, intending to make the children resistant or even immune to HIV.
While this might seem like great news, in reality, there’s no way to know how this genomic editing will affect these children in the future. And they will likely be forced to live a life in which they’re overly monitored and smothered.
The Cost of CRISPR-Based Treatments
Gene editing with CRISPR is easy and cheap. For less than $100 in supplies, any researcher can make thousands of probes that cover an organism’s entire genome. Then why is it so expensive to use it as a treatment?
We already saw the different medical applications that CRISPR-Cas9 technology can have and it all seems extremely promising in clinical trials. What we don’t see is the price tag that goes along with these types of treatments.
Genomic medicines can range from $500,000 to $2 million per patient. Public health systems could never cover these expenses, private insurers also aren’t willing to cover them and so these treatments continue to be out of reach for most patients.
Pharmaceutical companies justify the high prices by saying that they’re needed to recover all of the expenses related to research, development, and manufacturing. With any new technology, they’re expensive in the beginning, and over time they become cheaper.
Unfortunately, this isn’t an option for every person that is suffering now.
The Future of CRISPR
When it comes to the future of CRISPR the possibilities are pretty much endless. This genome editing tool has transformed the field of genome engineering and will likely continue to have an impact across many other industries.
More and more clinical trials are being approved, meaning that the possibility of curing human disease through DNA editing is getting closer. Researchers are also finding new ways of applying this technology to solve real-world problems like epigenome editing, infectious disease research, and the conservation of endangered species.
Using CRISPR-Cas9 routinely in humans probably won’t happen soon. But knowing more details about our genome, how every little piece interacts with all others, and then creating global policies regarding genome editing, will get us there sooner.
CRISPR-Cas9 is a genome editing tool that changed the landscape of modern medicine. Its capability of deleting and inserting new genes into DNA has made it a useful resource in cell and gene therapies, diagnostics, bioenergy, and many other applications.
It still raises a few ethical concerns, especially when it comes to editing germline cells and embryos, and it is a highly expensive therapy. However, with more research and stronger policies, there will come a day where CRISPR technologies will be used routinely in humans, hoping to cure diseases through DNA editing.
