The Ethics of Gene Editing

Most of my life has been surrounded by "ethics." Both my parents are lawyers and they are very knowledgeable about the law. I remember hearing debates over different laws and cases since I was little. If I was ever confused about certain political and government events, I could always trust my parents to understand the situation. Later in her career, after 17 years of practicing law in a firm, my mother transitioned to working for the New Jersey state government. My mother took a position as the chief ethics officer and she has been working on ethical dilemmas involving the State. I have learned much about what is "right" and "wrong" from my parents' careers, including issues involving criminal matters or the importance of writing a thank you note when I receive a gift. 

When I was first introduced to the idea of gene editing or CRISPR, I was morally conflicted. As I human being, I felt both a need for gene editing in order to improve humanity, but I also experienced moral objections at the thought of editing natural human life and the fear of a dystopian or Gattaca world in our future. Is gene editing a necessity or is it human interference in something that should be left alone?

CRISPR-Cas9 bound to a DNA strand

What is CRISPR?

First, it is important to establish what CRISPR is and how it works. CRISPR is actually short for the term CRISPR-Cas9. CRISPRs are specialized sequences of DNA and Cas9 is an enzyme that uses the CRISPR sequences to recognize and then cut sequences in other DNA. This system was actually developed from bacteria and archaea's natural defense mechanisms against viruses. This mechanism uses CRISPR-derived RNA and Cas proteins to defeat and destroy DNA of a foreign presence. 

CRISPR, which stands for "clusters of regularly interspaced palindromic repeats," has two distinguishing traits:  (1) its nucleotide repeats and (2) spacers. These repeated sequences are distributed throughout the CRISPR region accompanied by spacers between the repeated nucleotide sequences. Using bacteria as an example, an experiment was performed by Rodolphe Barrangou and a team of researchers, which discovered CRISPR's role in regulating bacterial immunity. Bacteria take spacers from viruses that have attacked the bacteria in the past and use the spacer as a memory in order to identify the virus and fight it off. If a spacer has been removed and the virus attacks the bacteria again, CRISPR is transformed into CRISPR RNA or crRNA. The Cas9 protein then binds to crRNA or tracrRNA, which stands for trans-activating CRISPER RNA, and these RNAs guide the Cas9 to a target site to make its ever-so-important cut to destroy the virus.

CRISPR-Cas9 is also involved in genome editing. CRISPR-Cas9 causes the insertion of a cut or break in DNA and then it tricks a cell's natural repair system to change the genome according to the manipulation by a researcher. The Cas9 protein may be programmed to cut any portion of a DNA strand by changing the nucleotide sequence of crRNA. To correct this cut, a cell will either use the "non-homologous joining method," which glues the cuts back together and usually introduces errors, or it uses a second method in which the cut is fixed by filling in the gap with a sequence of nucleotides based off of a short DNA template strand that scientists supply. 

CRISPR cutting out segments of DNA

Pros

CRISPR is a revolutionary improvement in the genome-editing field. It makes the editing of genomes significantly easier, faster, and more accessible. CRISPR gene editing is being tested for the potential treatment of many genetic diseases, which may save lives and reduce the suffering of many people. Specifically, CRISPR gene editing allows for the ability to target both monogenic and even polygenic diseases, including cancer and diabetes. Gene editing may also improve crop quality and production by adding in genes that create disease resistance in plants (and perhaps the same may even be achieved in humans).

Cons

One moral concern relates to the safety of the individual whose genome is edited. A problem that may occur is if the gene is edited in the wrong place and, instead, of fixing the genetic defect, the CRISPR process creates another genetic defect for the individual. Alternatively, mosaicism may result, which is what occurs if some cells of an individual are edited and others are not. In this case, the individual may or may not still carry the edit. These concerns are amplified if the edit is done to the germ-line because then not only is the individual affected, but her or his offspring are as well. Similarly, this may also occur in crops whose genes are edited because the edits may spread in the wild and disturb the ecosystem.

Another problematic issue is the non-therapeutic use of gene editing and CRISPR being used for enhancement purposes. For example, some parents may want to edit the genes of their children so that they are faster, stronger, or more intelligent. The use of CRISPR for enhancement purposes introduces social justice issues into the scientific realm. Genetic modification, which is a very expensive process, may also only be available for the wealthy and may in the long run encourage and widen wealth gaps in our society and in people's access to health care. Finally, genetic modification may possibly create a clash of different groups of individuals:  those who are genetically engineered versus those who are not. 

CRISPR is often compared to scissors cutting a DNA strand

What do you think?

After hearing both sides of the argument, what do you find to be too far outside of your moral jurisdiction? CRISPR, for many, is a slippery slope between social catastrophe and revolutionary discovery. Is it possible to have a reduction in diseases without creating a more divided class system with which our society is already plagued? 

Personally, I believe CRISPR is an important tool that scientists should utilize to reduce disease and extend the lives of many people. However, I believe that CRISPR should be heavily regulated and only deployed for gene editing in life or death situations. I am fearful that if CRISPR is not regulated, gene editing could lead to a dystopian world with artificial or gene-altered people.

More Information

If you are still undecided after examining both sides of the CRISPR debate, HHMI has an informative BioInteractive that uses a simulation to explain CRISPR. There is also a wonderful Radiolab podcast that explores many of the different ethical opinions on CRISPR and provides further information surrounding the recent developments in CRISPR technology.