Prof. Markus Affolter about CRISPR
In 2012, Emmanuelle Charpentier and her colleagues published their revolutionary discovery: the gene scissors CRISPR/Cas9. Just a few months ago, the Chinese researcher He Jiankui caused a worldwide furor for creating CRISPR designed babies. And this promptly raises the question of how far science is allowed to go. In the past few years, many researchers have established this technique in their labs, including the team headed by Markus Affolter. “CRISPR combines many advantages. The method is simple, cheap and above all efficient and extremely precise. Furthermore, it can be used anywhere, in plants, animals, bacteria and even in human cells.”
Using CRISPR, the genome can not only be edited selectively, but also whole genes can be removed, modified DNA sequences inserted and specific locations marked. All that is needed is an RNA molecule that specifically recognizes the target sequence in the genome and determines the cleavage site by recruiting the Cas9 protein, which then cuts the DNA at the desired location. "CRISPR is sensational for research," says Markus. "Without CRISPR many experiments would take considerably longer, and some would even be impossible." He considers the application of CRISPR in basic research to be safe, particularly as there are no commercial interests and release experiments.
Yet the application spectrum of CRISPR is extremely broad and goes far beyond research. For example, CRISPR-modified mosquito populations could stop the spread of malaria or dengue fever and genetic defects could be corrected to cure people with hereditary diseases. The potential is also great in the field of plant breeding. “Due to climate change, we need robust varieties that better tolerate drought and heat. CRISPR is not only much more efficient but also less risky than classical breeding methods.”
However, particularly for applications outside research, there are many concerns and risks that need to be discussed, both at the scientific and social level. Questions concerning the usefulness of gene therapy in a specific case need to be answered, as CRISPR is not error free. In response to the CRISPR-edited babies, researchers have recently called for a global moratorium and currently prohibit any human germline editing. Editing the germline carries risks, as the modifications are passed on to the offspring. This has serious consequences – not only medical, but also social, ethical and legal ones. “Intervention in the human germline is currently an absolute ‘no go’ ”, emphasizes Markus. “It is neither ethically justifiable nor wise. In many countries, including Switzerland, it is prohibited by law with good reason.»
The fast pace at which genetic engineering continues to develop requires a close exchange between researchers, politicians and society. “As scientists, we should not stay out of the social debate. However, when discussing the use and the limits of CRISPR, it is important to precisely define the scope of application. Apart from the varied applications in basic research, I personally see an enormous potential for CRISPR in the future, particularly in the field of cell therapies in humans or in plant breeding.”