Thinking Towards the Future of CRISPR/Cas9

ALAN YANG

CRISPR/Cas9 is a powerful new genome editing tool, but it’s also the source of a fiery ethical controversy. A cheap, quick, and highly accurate method to modify specific gene sequences, CRISPR/Cas9 promises to facilitate genetic research and perhaps even cure genetic diseases. (1) But since CRISPR/Cas9 technology works on any gene, it theoretically could also be used to eliminate genetic “weaknesses” in the DNA of human embryos and to artificially endow them with desirable traits—say, perfect pitch. (2) In the distant future, CRISPR/Cas9 or a similar innovation could  be used to engineer “super-babies”, just as one might assemble a “have-it-all” car with bullet-proof windows, high gas mileage, and a sleek frame. Given that CRISPR/Cas9 has the potential to alter the human genome in unprecedented ways,  it is worth considering the ethical implications of this technology in advance. In my opinion, CRISPR/Cas9 should be limited to scientific research and disease therapy, because if we allowed such tools  to be used for non-research and non-therapeutic means, we would open the door to the nightmare of eugenics and the loss of human diversity.

A CRISPR-associated protein. Image via Wikimedia Commons, Creative Commons Attribution.

First detailed in 2012, CRISPR/Cas9 works by co-opting a natural mechanism that protects bacteria against viruses. These bacteria  synthesize short RNA molecules which form complexes with bacterial proteins such as Cas9. (3) Once bound to Cas9, the short RNA molecules search for complementary viral DNA sequences to pair up with. If a perfect match is found, Cas9 “snips” and degrades the viral DNA, keeping viruses from replicating and harming the bacteria. (4) When used in human cells, CRISPR/Cas9 uses artificial RNA designed to pair up with certain human gene sequences and cuts human DNA. Scientists can then interfere with the natural DNA repair process to induce mutations in normal genes or replace mutated genes with regular genes. (5)

The superior speed and efficiency of CRISPR/Cas9 represents a remarkable leap in research, as it can accelerate the identification of genes that are associated with certain human traits and diseases and facilitate the development of therapies to correct mutant gene variants. (6) As a result, CRISPR/Cas9 promises to be an invaluable method for understanding the roles of human genes and developing cures for genetic disorders. But if the use of CRISPR/Cas9 is not restricted, it could have troubling implications. If the technology became available—certainly not an impossibility in this era of swift scientific advances—who would stop couples from using CRISPR/Cas9 to endow their babies with savant IQs, uncanny athleticism, and good looks? Parents might compete to craft the “best” babies, and those who were genetically less fit would be neglected. As Columbia University Professor of Biological Sciences Robert Pollack notes, the pain that individuals who are less genetically-endowed would feel when surrounded by super-human peers is unimaginable. (7)

Dr. Michael Nestor, a neuroscience researcher at the New York Stem Cell Foundation who uses CRISPR/Cas9 in his work, raises another problem with the indiscriminate use of CRISPR/Cas9: the loss of human diversity. For instance, scientists might use CRISPR/Cas9 to knock out the genes that predispose people to anxious or over-contemplative personalities. Though this would increase the number of “normal” people, it might also lead to a loss of future van Goghs or Tchaikovskys, whose art was inspired by feelings of intense sorrow. (8) To be sure, such genetic aims are still scientifically unachievable; we have yet to identify all the genetic variants that contribute to such complex traits. To be ethically prepared, however, we should still consider the consequences of tweaking various human characteristics. This thought experiment demonstrates the frighteningly complex biological and social consequences of modifying human genes.

…using CRISPR/Cas9 to treat or prevent sickle cell anemia or certain cancers that we understand is responsible use, but using it to correct nearsightedness or to boost one’s immune system when there is no present malady starts to sound irresponsible.

 

Therefore, we must limit our use of CRISPR/Cas9 to lab research and therapy for diseases whose genetic components we sufficiently understand. It is admittedly difficult to establish a clear definition of what constitutes a disease, and future research will have to proceed on something of a case-by-case basis. As a general guideline, though, we should  avoid using CRISPR/Cas9 on conditions that are not generally considered illnesses or whose underlying genetic causes are still unclear. For instance, using CRISPR/Cas9 to treat or prevent sickle cell anemia or certain cancers that we understand is responsible use, but using it to correct nearsightedness or to boost one’s immune system when there is no present malady starts to sound irresponsible.

Technologies like CRISPR/Cas9 open up a new and exciting world of possibilities, but we should always be mindful of the threats they pose, too. It’s all too easy to get caught up in the glamor of scientific advancement and forget about the ethical impact of our discoveries. In the case of CRISPR/Cas9, let’s exercise a little caution—and a little humility. Human beings are far too complex, far too wonderful, to be designed like luxury cars.

Works Cited:

  1. Wu, Yuxuan, Hai Zhou, Xiaoying Fan, Ying Zhang, Man Zhang, Yinghua Wang, Zhenfei Xie, Meizhu Bai, Qi Yin, Dan Liang, Wei Tang, Jiaoyang Liao, Chikai Zhou, Wujuan Liu, Ping Zhu, Hongshan Guo, Hong Pan, Chunlian Wu, Huijuan Shi, Ligang Wu, Fuchou Tang, and Jinsong Li. “Correction of a Genetic Disease by CRISPR-Cas9-mediated Gene Editing in Mouse Spermatogonial Stem Cells.” Cell Res Cell Research 25.1 (2014): 67-79. Web. 11 July 2015.
  2. Qi, Lei S., Matthew H. Larson, Luke A. Gilbert, Jennifer A. Doudna, Jonathan S. Weissman, Adam P. Arkin, and Wendell A. Lim. “Repurposing CRISPR as an RNA-Guided Platform for Sequence-Specific Control of Gene Expression.” Cell 152.5 (2013): 1173-183. Web. 27 June 2015.
  3. Jinek, M., K. Chylinski, I. Fonfara, M. Hauer, J. A. Doudna, and E. Charpentier. “A Programmable Dual-RNA-Guided DNA Endonuclease in Adaptive Bacterial Immunity.” Science 337.6096 (2012): 816-21. Web. 8 June 2015
  4. Jinek, M., K. Chylinski, I. Fonfara, M. Hauer, J. A. Doudna, and E. Charpentier. “A Programmable Dual-RNA-Guided DNA Endonuclease in Adaptive Bacterial Immunity.” Science 337.6096 (2012): 816-21. Web. 8 June 2015.
  5. Jinek, M., K. Chylinski, I. Fonfara, M. Hauer, J. A. Doudna, and E. Charpentier. “A Programmable Dual-RNA-Guided DNA Endonuclease in Adaptive Bacterial Immunity.” Science 337.6096 (2012): 816-21. Web. 8 June 2015.
  6. Qi, Lei S., Matthew H. Larson, Luke A. Gilbert, Jennifer A. Doudna, Jonathan S. Weissman, Adam P. Arkin, and Wendell A. Lim. “Repurposing CRISPR as an RNA-Guided Platform for Sequence-Specific Control of Gene Expression.” Cell 152.5 (2013): 1173-183. Web. 27 June 2015.
  7. Pollack, R. “Eugenics Lurk in the Shadow of CRISPR.” Science 348.6237 (2015): 871. Web. 8 June 2015.
  8. Ethics of CRISPR Gene Editing in Human Stem Cells. Dir. Michael W. Nestor. Perf. Michael W. Nestor. Youtube. N.p., 23 Apr. 2015. Web. 8 June 2015.

Alan Yang is a staff writer for Brevia. He can be reached at alanyang01@college.harvard.edu.