Genetic manipulation in the kitchen: a good idea?
Perhaps you would like to make bacteria antibiotic-resistant or otherwise genetically manipulate them in your own kitchen. It is possible: the American bio-hackers’ collective The Odin ships DIY boxes around the world containing the genetic cut-and-paste technology known as CRISPR. This hyped gene-editing technique—which Chinese scientists had used to genetically enhance babies several years ago—will be sent to your home for €300. Evelien Smits, a professor of tumour immunology, explains the technique and its benefits in human applications, and bio-ethicist Kristien Hens points to possible risks and opportunities.
Molecular scissors
It sounds like a name for a crunchy breakfast cereal, but CRISPR actually stands for ‘clustered regularly interspaced short palindromic repeats’—a revolutionary gene-editing technology that makes it possible to alter specific genes in organisms, including humans. The CRISPR technique is based on a natural defence mechanism that some bacteria have against viruses. Evelien Smits, a professor of tumour immunology and cancer immunotherapy, together with postdoctoral researchers Jorrit De Waele and Jonas Van Audenaerde, try to provide a comprehensive explanation.
‘The DNA of organisms stores a large amount of information, such as what you look like and whether you can get certain diseases. Some organisms, like some bacteria, have a kind of memory in their DNA. We refer to these pieces of DNA as CRISPR sequences. Now, consider a special pair of scissors known as “Cas9”. These miniature scissors can very precisely cut DNA at a specific location. To tell Cas9 where to cut, scientists create a kind of GPS, known as ‘guide RNA’. Once the guide-RNA/Cas9 team arrives at the target gene on the DNA, Cas9 cuts it like scissors. This creates a break in the DNA. The cell wants to repair the broken DNA strands, so it goes to work. Sometimes it makes mistakes in the process, and this is where it becomes interesting. These errors can cause changes in the gene, such as switching off, replacing or adding new information. This is thus how we get mutations.'
Revolutionary speed
Absolutely clear. ‘This technology has been around for only 10 years’, Smits attests. ‘The Nobel prize was not presented to the discoverers until 2020, and clinical trials in hospitals are already under way to apply the technique to humans. This is all proceeding much more quickly than usual. The precision with which CRISPR-Cas9 cuts is unprecedented. In cancer immunotherapy, CRISPR helps to modify patients’ cells in the lab, so that they can properly recognise and destroy cancer cells, in addition to resisting the techniques that cancer cell techniques use to suppress the immune system.
CRISPR technology has been around for only 10 years, and clinical trials are already in progress in hospitals. The speed and precision of the technique are unprecedented.
The clinical trials are still ongoing, but pilot animal studies have already revealed promising results. Although the technique is not yet 100% flawless, it is safer than any previous treatment. It is also much faster: whereas we needed two months a decade ago, we now have everything cut and done in two hours. We work go much faster in research, and develop new treatments more quickly.'
Even more specific cutting
‘We would now like to investigate further how we can ensure that CRISPR will very specifically adapt only the cells we need’, notes Smits. ‘For example, with sickle-cell anaemia, a type of blood cancer, people have abnormally shaped red blood cells. You just have to modify the blood stem cells at that point, because only they are responsible for those faulty red blood cells. For that to happen, those aberrant cells must have a unique characteristic, and that is not simple. Unfortunately, the list of diseases we can solve by manipulating one gene is also not that long. Huntington’s disease, an inherited brain disorder, is one of them, as are cystic fibrosis and haemophilia, a clotting disease. If you bring more than one ‘guide’ into the system—and many diseases unfortunately require the manipulation of multiple genes—the risks become greater.'
Designer babies
To learn about the risks, we turn to bio-ethics research professor Kristien Hens. She has recently written a book entitled Toevallige ontmoetingen: Bio-ethiek voor een gehavende planeet (Random Encounters: Bio-ethics for a wounded planet), in which she examines various topics, including the CRISPR technique. ‘People wonder whether we’re going to create designer babies, or whether we’ll be able to produce bio-weapons at home in the near future.'
The CRISPR technology, however, is primarily a convenient tool with many positive applications in various domains. ‘For example, you could make certain crops more drought-resistant. This could be very useful in times of climate change. Prophets of doom often associate CRISPR with frightening Frankenstein situations, but I think it’s important not to be too hasty with our judgements.'
People versus embryos
‘With regard to the CRISPR-at-home-or-school kit, as a human being, my first thought was indeed, “Oh! Cool!”’ admits Hens. ‘I think it would be great if this could be used in schools, as CRISPR is the technology of the future. As a bio-ethicist, however, I obviously see the dangerous aspects, such as the creation of antibiotic-resistant bacteria. We obviously don’t want this to lead to the escape of bacteria that could potentially cause another pandemic.'
The use of CRISPR is justified if the risk of damage or suffering would be greater without using the technology.
This even though she thinks that such concerns are grossly exaggerated. ‘Although CRISPR is certainly not yet without risk, the main thing here is to weigh the advantages against the disadvantages’, argues Hens. ‘I think CRISPR could be a fantastic tool for biomedical use in humans. We should nevertheless draw a distinction between applying it to people who are already suffering from serious genetic disorders and applying it to embryos. The first category involves people who already exist, and who can therefore make their own decisions and cannot be helped in any other way. The latter category involves creating other human beings who do not yet have control any over their genetic make-up.'
Weighing risks
‘In the past, genetic engineering was much more risky’, stipulates Hens. ‘Everything is much safer now, but we shouldn’t be so simplistic as to think that genes can be easily replaced, like with Lego blocks. With CRISPR, the cutting and pasting of genes can indeed have unintended consequences, so we must weigh the risks carefully.'
In the case of embryos, the aim is to use the technology to prevent genetic diseases in people who are at high risk of passing them on to their children. ‘For people who know they are carriers of serious genetic disorders and for whom alternatives (e.g. embryo selection) are not applicable—and for whom embryo or sperm donation is not desired—the genetic modification of embryos might be justified. The use of CRISPR can nevertheless be justified only if the risk of harm or suffering without the use of the technology is much higher than the risks caused by the technology itself.'