By Elianna Miller
In late 2018, “CRISPR babies” made news worldwide, and they are now coming back to the spotlight. When He Jiankui made genetically modified embryos that grew into twin girls with HIV immunity, people were outraged. He didn’t discuss his plans with his scientific community, and the procedure was deemed unnecessary and risky. These so called “CRISPR babies” were viewed with great controversy and caused a halt in the global scientific community on gene-edited embryos.
Now, Russian scientist Denis Rebrikov has announced his desire to produce CRISPR babies that can hear from parents with recessive genetic deafness. Because both parents have an altered copy of a gene related to hearing, any child they naturally conceive would be deaf, too. The participants want to provide their children with the ability to hear. Rebrikov plans to consult scientific communities and explain the benefits of the process, unlike He.
So, what is CRISPR? It’s a groundbreaking technology that is often seen in the news but less often well understood. Short for Clustered Regularly Interspaced Short Palindromic Regions, multiple repeats of the same 30 or so base pairs are separated by different genes of interest (spacers). Spacers serve as a guide for an enzyme, usually Cas9, to cut specific pieces of the genetic code. When this “faulty” DNA is cut, that gene is essentially turned off.
The cutting also acts as marking, and other molecular components can guide new DNA to that marked spot. This unfortunately doesn’t always work perfectly. Since there are so many repeats, the cutting enzyme can go to the wrong spot, editing unintentionally. Rebrikov still wants to use this process to insert “hearing genes” into embryos regardless of the imperfect mechanism.
Many ethical dilemmas arise here. There is no consensus on who gets to decide when CRISPR should or should not be used. Right now, the ability to hear is a product of environment and parental genes, and scientists like Rebrikov are attempting to change those factors with this new technology.
The Center for Genetics and Society talks about CRISPR in the context of disability rights, and the range of perspectives needed when making decisions about cutting genes from embryos. They note that removing genes linked to certain characteristics is marking them as tragic, implying impossibility of a good life. How can we respect people living with certain conditions that we are choosing to eliminate from others? Also, where do boundaries lie, and how do we draw the line on what genes can be edited? If we can edit out certain genetic disorders, what will stop us from selecting for certain eye colors, heights, or intelligence capacities? These are difficult questions that will be debated again and again as CRISPR gene editing technology advances and begins to touch more lives.
References:
https://www.sciencedirect.com/science/article/pii/S216225311630049X
