Humans dream about being able to modify themselves to perfection, or to their satisfaction – “What if I’m just a little bit stronger, a little bit taller, or can focus really just a little bit more?” Genome editing, a technology that rose during the 1990s, although usually oversimplified, becomes a term that appears often in literature, movies, and video games.
In real life, however, although genome editing has been frequently tested on lab animals, such as mice and zebrafish, the birth of genetically edited twins in 2018 provoked gigantic tides of controversies: not only genome editing itself is a relatively immature technology, the ethical problems following it have also made the real-life application of this technology extremely dangerous.
Image from Wikimedia Commons
The most common genome editing technology now is called Clustered regularly interspaced short palindromic repeats (CRISPR), which has a higher success rate and is much less costly and time-consuming that its three predecessors, Homologous recombination, Zinc-finger nucleases (ZFN), and Transcription activator-like effector nucleases (TALENs). Enzymes, proteins that act as biological catalysts, as we have learned, have various functions: speeding up chemical reactions in the human body, binding molecules and altering the shape, transferring signals between cells, just for a few examples. Similarly, CRISPR works with an enzyme that enables it as a tool of genome editing.
When CRISPR was first discovered by humans, the function of CRISPR that humans know is defending bacteria against DNA viruses and plasmids: the CRISPR-associated protein 9, as known as Cas9, works with CRISPR and cuts DNA. Utilizing this function, humans create a RNA template that matches a target DNA sequence. As the created RNA of CRISPR binds with the targeted DNA that shares the same sequence, the Cas9 enzyme is led to the targeted DNA and cuts the genome, fulfilling the goal of editing the genome.
Image from Wikimedia Commons
However, even with the improvements scientists had made, the technology is still largely immature and not in control; already extremely rare, all experiments of genome-editing on humans are strictly regulated by the government. Yet, the technology was used on the twins mentioned earlier to edit the genome. The event is known as the He Jiankui Affair, named after the directing scientist. As the in vitro babies of an HIV-positive father, the twins had their CCR5 Gene – a gene whose deletion means resistance to a certain type infection – edited while they are still embryos in a laboratory environment, in order for them to possess genetic resistance toward HIV. Set aside the accusation that the experiment conducts no technological breakthrough, having no real effect on preventing HIV infection, and can even be unsafe, thus irresponsible to the twins, the usage of genome-editing on human embryos was largely criticized ethically, even when He Jiankui claims his intentions to be good. The criticizers worry about genome-editing on human is nothing different than opening the box of Pandora: if one person is able to afford genome therapy while another is not, the basic rights of life is discriminated by the amount of wealth; the potential uses of genome-editing on physical traits outside of serious medical issues would be a provocation to nature; etc. The Wild West of genome-editing is far too taboo for humans right now.
Other voices say, however, the birth of the twins is a great step for humans – If the American frontier remained unexplored, the prosperity of the west coast would not exist. Even though his genome-editing experiment is largely unregulated and unknown by the state, the scientist He Jiankui has been sentenced for three years and fined by 3 million CNY, approximately 430,000 USD. If this technology is going to be widely used in future, then for now, just as what the former adviser of the controversial scientist said, people “need to do it properly and with proper respect for the people who are involved, and the field.”