CRISPR-Cas9: I’m sure you’ve heard all about it before. No? Ah, I keep forgetting not everyone’s life revolves around pipetting solutions in research labs. Allow me to explain!
We’ve all seen GATTACA, right? It’s a movie which takes place in a world where human genetic engineering is the norm; if you had rich parents, that likely meant you had genes inserted in you to make you stronger and smarter than the less-than-fortunate children. Well if that doesn’t sound like a world you want to live in, don’t panic, that isn’t happening (at least for now). We might, however, be in the foothills of GATTACA due to Crispr-Cas9 technology. Crispr-Cas9 is a gene editing tool that is able to, very accurately, change the DNA of any organism, including humans. In short, gene editing is a process to remove (or add) genes from an organism (i.e. removing a gene that is linked with higher prevalence of Alzheimer’s disease in later years).
In recent years, there has been an increase in the number of research labs using Crispr-Cas9. Google Scholar is a search engine which tracks every scientific publication. In 2012, the term “CRISPR-Cas9” yielded 2270 hits. Just three years later in 2015, that number has more than doubled to 5570. Google Trends also parallels the rising interest in gene-editing: there are more Google searches using the term “CRISPR” than ever before (figure 1). This by no means is a conclusive statistic, but it does highlight the trend we’ve seen in recent years: gene-editing is becoming more and more prominent and is here to stay. Because gene editing has become increasingly easy to perform (with accuracy) labs, questions arising the potential applications to human gene editing and the ethics surrounding that are now being discussed. The International Summit on Human Gene Editing was held on December 3rd at the U.S. National Academy of Sciences (NAS) in Washington D.C.
Figure 1 - Google trends for "CRISPR" reached an all time high in December 2015.
Click the graph to view the full data.
The consensus of the meeting was that safety issues and risks involved with editing human genes would need to be assessed prior to pursuing it further. Additionally, there would need to be societal agreement on the types of gene editing that are appropriate. This means that we will not be seeing designer babies for a long time, even if the technology to do this already exists. The meeting highlighted that it would be very difficult to predict the harmful effects genetic editing may have on offspring, especially taking into account the differing environments humans experience around the globe. It is well established that a combination of genetic and environment plays into a person’s development. A genetic change for one person in one context may not translate to the same changes in another person in a different context (i.e. climate differences, UV exposure, pollution rates, smog etc.). Furthermore, if scientists choose to edit genes, then future generations will carry these alternations. Once introduced into the human population, these genetic alterations would be very difficult to remove should they be deemed not safe.
Going forward, these are all very important questions the scientific community needs to be continually addressing. The one area where we might begin to see human gene-editing are with somatic cells. Somatic cells are cells in the body, including skin, bone and blood, which are not passed onto future generations (i.e. every cell in the body except the sperm or the egg). From this meeting, scientists agreed that there are many promising and valuable clinical applications of gene-editing on somatic cells. But, before patients are subjected to gene editing, there would need to be a thorough analysis of risks involved. The benefit of somatic cell gene editing is that, should there be an unpredicted adverse affect (not very likely at all, due to the stringency of testing that would precede this), this would be contained in only one patient and would not spread.
Overall, while researchers are enlivened by the promise of CRISPR-Cas9 technology, scientists are asking the right questions and establishing gene-editing standards for the world to follow, thus ensuring that GATTACA still only exists in Hollywood.