Picture yourself as an expectant parent, just told your baby has a genetic abnormality. During this agonizing moment, various thoughts will likely race through your head—Will my child grow up normal? Happy? Self-sufficient? Can I financially support the condition? Now imagine that instead of words of comfort, the doctor said that treatment was not only available, but also reliable and affordable. Should you take it?
Soon, we will have to face similar decisions and much more. CRISPR-Cas 9, a genetic modification tool developed in 2012 by Jennifer Doudna and Emmanuelle Charpentier, is revolutionizing research and medicine, whilst raising ethical concerns.
The discovery of CRISPR-Cas 9 originated from research on bacteria immunology. CRISPR (Clustered Regularly-Interspaced Short Palindromic Repeats) are segments of DNA in prokaryotes that play a role in their adaptive immunity. In between each repeated segment are fragments of virus DNA gathered from previous attacks. The Cas 9 protein recognizes these virus DNA fragments and can effectively cut those particular sequences upon future attacks. By utilizing the Cas 9 protein’s ability to target specific DNA, Jennifer Doudna and Emmanuelle Charpentier successfully created a new DNA editing tool.
To grasp CRISPR-Cas9’s potential in revolutionizing genomic editing, we need to understand it in the context of its predecessors. Previous editing tools include zinc finger nucleases (early 2000s) and TALENs, both of which required custom proteins to be made for each DNA target, making the process difficult, time-consuming, and expensive. Since the Cas 9 protein can be programed to target different DNA, CRISPR-Cas 9 circumvents the need for custom proteins, allowing the editing process to be much easier and simpler. And while previous methods cost $5,000 or more, this new technology costs as little as $30. Thus, although CRISPR-Cas 9 is not the first genetic editing tool to be invented, it is the first to be inexpensive, accessible, and widely used in research facilities.
At this moment, the technology has mainly been used in animal research—such as in mice, monkey, and the fungus Candida albicans, which causes yeast infection. But there have been a few notable attempts in human cells. Researchers in California have successfully removed the HIV virus DNA from infected human cells, indicating a promising HIV treatment method. And, alarming to many, scientists in Sun Yat-sen University, China have altered genes in human embryos. The research itself was considered ethical because all embryos carried a chromosomal defect that made them unviable. However, results indicate that our current gene editing skills are unreliable: the tool cut the genome at many unintended sites. And more importantly, practical concerns aside, many people are worried about the ethics of altering human embryo DNA. Therefore, in late winter of 2015, a global moratorium was made on making inheritable changes to the human genome. The only other precedent of such a moratorium occurred upon the discovery of molecular cloning.
The debate continues as to whether the moratorium should be permanent, or lifted when CRISPR-Cas9 becomes more reliable. Would we ever want to edit human genes? Should we? Unlike gene therapy, which alters the body’s tissues, genetic edits made by CRISPR-Cas 9 are heritable, which means that one gene edit could have a huge effect in future generations. Is saving one life worth the risk of jeopardizing millions?
And where do we draw the line in human editing? A potential effect of germ line editing in hereditary disease is genetic enhancement, which would allow for “designer babies.” In order to prevent genetic enhancements, we would have to regulate the CRISPR-Cas9 technology to only be used in legitimate medical conditions. Such an attempt can be difficult given the ease and inexpensive qualities of the tool that have made it so popular and widespread. Will the use of CRISPR-Cas9 on humans ultimately result in a “Gattacan” society, with a source of discrimination embedded in our very genome?
Scientists against human gene editing also argue that the long-term side-effects of altering our DNA are unknown. Certain traits are governed by multiple genes, and likewise certain genes may affect multiple traits. We still lack a comprehensive knowledge of every gene and allele in our body, so perhaps gene alterations are rash and irresponsible to the patient’s well being.
On the other hand, others believe that we should be open to the idea of human genome editing in the future, and that its ability to cure diseases and improve lives outweigh the potential negative effects. To them, not harnessing the technology is wasteful and negligent. Furthermore, an absolute ban of human genome editing could drive it to black markets, making the practice unregulated and dangerous.
Our decisions with regards to CRISPR-Cas9, capable of both great discoveries and destructive manipulations, is the ultimate test of our society’s moral compass. With this power comes a responsibility to not only our current society’s welfare, but also the wellbeing of generations to come.
Wade, Nicholas. “Scientists Seek Moratorium on Edits to Human Genome That Could Be Inherited.” The New York Times. The New York Times, 2015. Web. 28 Feb. 2016.
Nature.com. CRISPR-Cas9 p. Web. 28 Feb. 2016.