Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology has been the buzz of the scientific community over the past few years for its ability to alter DNA. The CRISPR/Cas9 technology offers promising results for various disease treatments, but this is sometimes overlooked. Instead, CRISPR is often equated with the idea of “designer babies” with the implication of designing a “perfect” human race.
I attended a lecture series on evolution at my local library a few summers ago, and someone in the audience asked about CRISPR. As opposed to a question, they accused the lecturer, who never mentioned CRISPR, and the scientific community of interfering with intelligent design. This was the first time I had ever thought about the potential ethical implications of CRISPR.
Since then, I’ve heard many people refer to CRISPR as “that designer baby technology” or some variation of this, focusing solely on the idea of sculpting future generations, not only to be disease resistant, but to be more intelligent, taller or have other specific physical features. By equating CRISPR to “designer babies,” we are limiting the scientific community from making significant advances. Instead, our society should be educating about and promoting the advancement of CRISPR/Cas9 technology.
It’s important to understand what CRISPR is, and how it works, to see that the notion of designer babies is ludicrous.
CRISPR is a natural form of bacterial defense and was initially studied as such. It was later that its gene-editing capabilities of CRISPR/Cas9 were discovered. CRISPR is analogous to a vaccine but for bacteria in the sense that it protects them from specific foreign invaders. This defense mechanism utilizes bits of viral genetic information found in the DNA of many bacteria. CRISPR regions are characterized by repeated sequences of bacterial DNA and spacer sequences of viral genetic information. These spacer sequences are acquired from viruses that have previously attacked the bacteria.
The bacteria are able to use this array of viral spacer sequences as a defense mechanism against similar invading viruses. This defense mechanism uses the Cas (CRISPR-associated proteins) enzymes to cut the bacterial DNA and insert the viral DNA, which creates a library of defensive spacer sequences.
The viral sequences in the bacterial DNA are translated into RNA, which can roam around the cell looking for viral invaders that contain genetic material to complement their sequence. If an invader is found, the RNA binds and, with the help of Cas9, destroys the invading pathogen by cutting the viruses double-stranded DNA.
The ability of CRISPR/Cas9 to cut double-stranded DNA is important because this system can be used to cut DNA in a way that allows for DNA sequences to be removed or added. This is exactly what has been done. The bacterial defense mechanism has been transformed into a programmable genome-editing tool.
This tool is designed such that the DNA will be cut only at the desired spot. Once the cell senses this break in DNA, it activates repair mechanisms that result in either the deletion or addition of DNA.
Knowing this, it is clear that CRISPR would be useful in preventing and treating genetic diseases caused by mutations because these mutations could be edited. CRISPR has a wide range of applications in disease prevention and treatment, the food and agriculture industries and in a phenomenon known as gene drive (the biased natural selection of genes).
So far CRISPR/Cas9 has been used for a variety of projects. For example, researchers are using this technology to create genetically infertile female mosquitos. This is part of an effort to decrease the frequency of malaria by decreasing the abundance of malaria-carrying mosquitos. The environmental implications of such an endeavor are unknown, but like most CRISPR/Cas9 projects, this is only in the preliminary stages. This means we do not need to worry about genetically-modified mosquitoes being released into the world tomorrow and upsetting entire ecosystems.
On many people’s minds is the application of CRISPR/Cas9 for the prevention and treatment of disease. It seems that such a technology would be useful in treating genetic diseases such as Huntington’s disease and cystic fibrosis, which are caused by specific mutations. CRISPR/Cas9 technology presents the opportunity to alter the genomes of preimplantation embryos to prevent genetically inherited diseases.
Researchers at the Oregon Health and Science University in Portland have used CRISPR/Cas9 to modify the DNA of human embryos to correct the mutation for hypertrophic cardiomyopathy, a genetically inherited heart condition which affects one in 500 people. They were able to successfully edit 72 percent of the embryos. This is only the second successful study using human embryos, following a study in China with a much lower success rate.
What does this mean for designer babies?
Currently, preimplantation genetic diagnosis, which screens sperm and eggs for genetic mutations, is commonly used with in vitro fertilization. While this allows individuals to select the sperm and eggs to use for procedure, use of the CRISPR/Cas9 system would allow any embryos with mutations to be edited prior to implantation.
The concern for many is that this gene-editing technology could be used to alter the human genome so that people will be smarter, stronger or taller and potentially incite a new form of eugenics. It’s easy to see how the power to control physical characteristics and capabilities could lead to a form of eugenics. However, it should be noted that the genes that encode for any of these characteristics are not determined by individual genes but involve the expression of hundreds of genes, many of which are unknown, making it virtually impossible to actually design a baby to have specific physical traits.
I’ve had the privilege of listening to Jennifer Doudna, one of the discoverers of CRISPR, speak about this tool and its promising applications.
“It feels a bit like a ‘one small step for (hu)mans, one giant leap for (hu)mankind’ moment,” said Doudna.
I think Doudna’s words really put the importance of CRISPR/Cas9 as a gene-editing tool into perspective. There is so much potential in this technology, but by causing initial panic over the prospect of designing a “perfect” human race by editing embryos, we instill a negative connotation with the words CRISPR/Cas9. Of course ethical questions will arise and should be addressed, but we cannot let the notion of “designer babies,” something not even achievable at the moment, stop us from advancing this technology. Applying a negative connotation to CRISPR/Cas9 could potentially decrease potential funding and slow the development of this research tool. Instead, we should be focusing on the good that can come from CRISPR and support research aimed at treating and preventing disease, as well as furthering our understanding of this fascinating biological mechanism.
