Written by: Josephine Chen '24
Edited by: Jason Johnston '23
The first designer babies—twin girls with genetically modified genomes—were born on November 25, 2018. Researcher Dr. He Jiankui and his team used CRISPR-Cas9, or Clustered Regularly Interspaced Short Palindromic Repeats, in an attempt to produce babies who are less susceptible to diseases. He Jiankui was imprisoned for his illegal and unethical medical practice.
CRISPR is a gene-editing tool that allows scientists to alter the DNA of organisms by adding or deleting genetic material at specific locations in the genome. First, scientists create a small piece of RNA, a type of nucleic acid similar to DNA, that is able to guide Cas9, an enzyme part of the CRISPR system, to the target DNA sequence in the genome. The Cas9 enzyme then binds to the DNA and cuts it. Cutting the DNA “turns off” the expression of the target gene. After the original DNA sequence is cut, scientists can add, delete, or alter the DNA to match a desired sequence . CRISPR is beneficial because it is powerful while also being inexpensive and relatively simple to use .
CRISPR is attractive to many researchers due to its ability to potentially permanently treat genetic diseases. He Jiankui and his team tried to combat HIV, smallpox, and cholera by eliminating the gene CCR5 . This is a natural mutation that is found in about 10% of Europeans . In their research, the team recruited heterosexual couples where the men were diagnosed with HIV . CRISPR can potentially be used to change the genes of early embryos before they are implanted into the mothers’ uteruses. With this mutation, HIV would not be able to infect the white blood cells in the babies .
One of the biggest oppositions to He’s research is that there is the possibility of altering every cell in the resulting baby after modifying the early embryo . Many argue that this will cause unexpected health consequences, but He reports that there have been no mutations found so far . However, scientist Joyce Harper from University College London states that years worth of research is needed to determine whether genome editing in the embryo will cause any consequences on the child .
There is also a lot of controversy surrounding the topic of human germline genome editing. Somatic cells die throughout the human’s life, but germ cells, which include sperm and egg cells, are passed down through generations . He Jiankui is interested in altering the genes inside of embryos, which is considered germline editing. Not only does this change the DNA of the baby, but it also affects the genes of future generations. Apart from the scientific concerns, there are also numerous religious and cultural offenses associated with changing the individual and their inheritance.
The story of human genome editing does not end there. In 2019, researcher Dr. Denis Rebrikov began editing eggs of hearing women to uncover how deaf couples can have babies without the genetic mutation that prevents hearing . Rebrikov plans on gaining a better understanding of the effects of off-target mutations in the donated eggs before attempting to implant the embryos. Currently, he is researching how CRISPR can be used to restore the gene associated with deafness, or GJB2. The ultimate goal of his research is to assist hearing-impaired couples to produce hearing-able children . Many worry that this will lead to a repeat of He’s unethical research.
Although the accuracy of CRISPR is continuously being improved, there are still many concerns about the regulation of the reproductive uses of gene editing. Some critics worry that lack of regulation would lead to “designer babies,” where the goal shifts from eliminating genetic diseases to customizing babies to have specific eye colors, intelligence, athleticism, etc. . This is another example of eugenics, as this technology can lead to the elimination of traits that the population perceives as inferior, including but not limited to deafness and Down syndrome . However, rather than accepting and treating such diseases, this approach attempts to do so by removing them from the gene pool entirely. There are also concerns about the access to this new technology. If only the wealthy are able to afford modifications in their children, an “elite” group may be created, further widening the effects of the socioeconomic divide .
Not all CRISPR trials are considered unethical and dangerous. More studies are now utilizing CRISPR technology in a more positive and safe manner. Recently, six people diagnosed with the rare disease transthyretin amyloidosis, a fatal condition where proteins misfold, form “clumps,” and cause permanent organ damage, received a gene-editing therapy treatment. All six participants noticed a decline in misfolded proteins, and a higher dose was associated with an even greater decline in levels of misfolded proteins .
However, several questions still remain unresolved: should CRISPR technology be used once it is proven safe to humans? What type of CRISPR editing should be allowed?
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