by Dr. Heather Kuruvilla
For most of us, “crisper” means the drawer at the bottom of the refrigerator. But if you Google CRISPR, which stands for Clustered Regularly Interspaced Short Palindromic Repeats, you will find that it is a powerful genomic editing technology. CRISPR can be used to inactivate or to edit genes. For more on how this technology works, see this article.
Obviously, any technology capable of editing genes becomes a possible target for gene therapy. Imagine if CRISPR could be used to cure genetic disease! This attractive possibility is why Chinese scientists recently used CRISPR to modify unviable human embryos.
The data themselves are telling. As reported by Genetic Engineering and Biotechnology News:
It noted that out of 86 human embryos that were subjected to genetic manipulation, 71 survived. Of the surviving embryos, 54 were genetically tested. Just 28 of these 54 embryos were successfully spliced. An even smaller number turned out to contain the desired genetic material. Also, off-target effects were seen.
The experiment has ignited a firestorm of controversy. Although CRISPR has shown promise in the laboratory, many scientists are wary of using this technology on human embryos when its safety and efficacy have not yet been proven. If the study above is any indication of what would happen in a viable human embryo, there appear to be a number of troubling results. “Off-target effects” were seen, meaning that unwanted genetic modifications were occurring. If this is the case, using CRISPR would potentially create genetic defects that are more severe than the disease we were trying to treat.
Another problem comes with the splicing success rate. “Just 28 of these 54 embryos were successfully spliced.” If we were using this technology to treat embryos with genetic defects, what do we do with the embryos if our treatment fails? Are these embryos then discarded, or are they allowed to implant with their genetic defect still present? I would argue that these embryos deserve our protection, as human persons created in the image of God. However, by treating them, have we caused further damage? In other words, are we raising the probability that these already genetically impaired embryos will not be viable?
CRISPR is an exciting new technology, and may even help us create adult stem cells for therapy. When it comes to genetic modification of human embryos, however, this technology is definitely not ready for primetime.