CRISPR-Cas9 is known for its revolutionary ability to aid in genetic engineering for eukaryotic cells. As described by Ran et al.’s Nature article, “the RNA-guided Cas9 nuclease from the microbial clustered regularly interspaced short palindromic repeats (CRISPR) adaptive immune system can be used to facilitate efficient genome engineering by simply specifying a 20-nt targeting sequence within its guide RNA”, or in other words, focusing on detailed genetic alternations by marking 20 nucleotides at a time for change. Its efficiency and specificity separate it from other genetic engineering technology of its time such as ZFNs and TALENs due to its “Watson-Crick base pairing…representing a system that is markedly easier to design, highly specific, efficient and well-suited for high-throughput and multiplexed gene editing for a variety of cell types and organisms”. Through its lower cost, ease of customization, cleavage pattern, and editing efficiency, CRISPR-Cas9 can be applied in various scenarios to genetically alter plants, bacteria, and animals. In regards to humans, advancements in this technology have opened doors to its medical applications such as treatment for sickle cell anemia, Huntington’s Disease, HIV, and cancers such as multiple myeloma.
University of Pennsylvania has been spearheading the exploration in CRISPR-Cas9 uses for myeloma treatment. As explained in this recent article detailing their clinical trails, researchers are working to genetic alter the patient’s immune cells as a path to further targeting tumors and inhibiting/reducing growth. Methodologies included harvesting cells from patient bone marrow and editing the T cells with the goals of more accurately targeting cancer cells before placing them back into the patient. This trial has also been applied for a sarcoma patient as on 2019. According to this article in 2020, also by Penn Medicine, they provided updates on the advancements of these trials stating “first, we can successfully perform multiple edits with precision during manufacturing, with the resulting cells surviving longer in the human body than any previously published data have shown. Second, thus far, these cells have shown a sustained ability to attack and kill tumors”. This article explains the significant progress of the antigen targeting being experimented with and hope in this process for quick and safe treatment in just one year of these trials being conducted despite the limitations such as off-target mutagenesis of which would be explored through larger trials in order to attempt in minimizing the occurrences of such modifications.
CRISPR use goes much further than life-changing medical treatments however, and expand in to much more high-end, superficial, uses. Genetic engineering in babies is a topic that has interested me for years since I first did a research project on it 3 years ago at the start of my UNC academic journey. This type of genetic engineering can be a result of many different goals but I see it all relatively under the concept of cosmetic embryo selection, “designer babies”. So much of the results of genetic engineering on the gene pool are still being discovered, yet, all species’ populations are found to have a naturally varying gene pool for the reason of differing traits allowing for ideal survival. For example, if blue eyes were seen to people as being more attractive than brown eyes this could potentially lead to parents favoring embryos showing the genetic makeup for this physical trait and could become a common thread in IVF selections. While they may be favored cosmetically, they also have a weakness: lighter colored eyes are unable to protect themselves from UV damage to the same capacity as those with darker eyes. This extreme scenario of cosmetic selection could then potentially lead to more people subjected to cataracts or vision loss due to UV damage. The overall purpose of this example is showing the domino effect that editing DNA can have on future generations, usually unintended. Messing with either scientific evolution, or what others consider to be “God’s plan”, is something that can have unforeseen long-term scientific complications that extend the risks beyond the benefits of decreasing a family’s stress or creating a “low-quality” life for a child, such as is often the attitude of parents finding out their child might have Down Syndrome or other life-altering genetic differences. While the implementation of cosmetic embryo/fetal screening and embryo selection/engineering, specifically through CRISPR, can be seen as moral and a means to ease people’s life stressors, it definitely has the ability to lead to the global issue of serious genetic pool degradation, and therefore if left unregulated, ultimately doing much more harm than good.
Ariana DeMattei's Microbiology Blog 