The Ethics of CRISPR and Genetic Engineering
With COVID-19 wreaking havoc across the globe, many research teams are looking for a cure. A team of Stanford bioengineers think they’ve found it. The technique they’ve called Prophylactic Antiviral CRISPR in Human Cells(or PAC-MAN for short) uses a genetic engineering tool called CRISPR to inhibit infection in human lung cells. It has been reported to reduce 90% of the virus in cells and is effective against 90% of coronaviruses, including the one that causes COVID-19. Although it needs countless months of testing before it can be used in humans, it serves as both a beacon of hope and as a testament to the power of genetic engineering. However, the applications of CRISPR extend much further than those of possibly preventing COVID-19.
Genetic engineering has been around for many years, but so far, CRISPR has been the most accurate and cheap to use technique. The genetic engineering tool, originally sourced from bacteria and archaea [1], uses specific DNA strands to create complimentary “guide” RNA strands. The “guide” RNA, in combination with a protein called Cas-9, scans the genome and cuts the matching strand. In bacteria, it is used to prevent attacks against bacteriophages [2]. If the bacteria survives the initial attack from the virus, it saves parts of the virus's DNA and makes complementary RNA strands. That way, if the virus enters the cell again, the RNA can “guide” the Cas-9 protein to the virus’s DNA and cut it before it can replicate in the cell. Applicable in any type of organism, CRISPR can be used to cut, insert and temporarily silence genes. This has been proven useful in a variety of organisms, including humans.
Genetic engineering has brought us many improvements in the scientific world. It has been used to manufacture insulin in bacteria and create vegetables that last longer on the shelves. However, because of its inaccuracy, it was never used on living humans. This has all changed with CRISPR. Unlike its predecessors, CRISPR is much more precise and for that reason, it has been utilized in a technique called gene therapy. This technique can be used to fight diseases like HIV and modify immune cells to better destroy cancer cells. This treatment only affects an individual in a specific area and can’t be passed onto offspring. However, problems lie in using CRISPR on developing embryos.
Using CRISPR in an embryo or reproductive cell is different from using it in body cells. This is because a CRISPR modified embryo will be capable of passing on their modified genes to future generations. CRISPR, while an improvement from other methods of genetic engineering, is not perfect. If a mistake is made, the embryo and future generations can be affected. We don’t know enough about the human genome and haven't developed a way to make CRISPR accurate enough to prevent these mistakes. Putting modified genes out into the gene pool is dangerous and could have consequences that are hard to measure and control.
An additional problem with using CRISPR on embryos is when it is used for enhancement rather than prevention. These enhanced embryos, coined “designer babies,” could become possible as our understanding of the human genome and CRISPR develops. Scientists could use CRISPR to increase intelligence, athletic ability and more. While this possibility seems attractive, it would likely only be available to the richest members of society. This would create a genetic gap between economic classes and give the rich unfair advantages over the rest. However, sometimes it is hard to draw the line between prevention and enhancement. Once the go-ahead is given to begin research and use on embryos, it could spiral out of control. He Jiankui, a Chinese researcher, has already utilized CRISPR on human embryos at the horror of many scientists worldwide. Although the changes he made were to prevent HIV and not enhance the embryos, it is an example of the need for global guidelines regarding CRISPR. In a quote from Dr. Jennifer Doudna, a UC Berkeley professor, “The science is going 1000 miles an hour, one of the roles that we as scientists need to play is to really communicate the power of this technology and how we can be responsible using it. For that conversation to carry weight globally, it really needs to be a conversation that involves scientists that are international.”
Although the threat of “designer babies” and human mutants looms over us, we can’t ignore the immense benefits and possibilities of CRISPR. If we are able to put guidelines in place to avoid misuse and understand the human genome enough to prevent mistakes, genetic diseases, cancer and other ailments could become a thing of the past. However, CRISPR is a relatively new technology. The world needs time to become informed about it and come to a consensus on where we need to draw the line. For the time being, CRISPR research and use should stick to adult cells. Although we are a long way away from being able to use CRISPR on embryos, research teams like the one at Stanford have proven time and time again, that CRISPR has the power to change the world.
1- A domain of single-celled organisms distinct from bacteria
2- Viruses that infect bacteria
References:
https://www.fiercebiotech.com/research/stanford-team-deploys-crispr-gene-editing-to-fight-covid-19
https://www.youtube.com/watch?v=jAhjPd4uNFY
Photo by ThisisEngineering RAEng on Unsplash
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