Nobel Prize in Chemistry 2020 goes to developers of the gene scissors CRISPR – for the most significant technological revolution of the 21st century in the field of bioengineering
Almost unnoticed by the public, less than ten years ago the most powerful tool in today’s biotechnology was developed, a technique that allows genetic engineers direct access to individual genes and their targeted manipulation. The name of it will soon be as well-known as DNA or AIDS: CRISPR. The acronym stands for „Clustered Regularly Interspaced Short Palindromic Repeats“ and describes sections of repeated DNA or RNA fragments in the genetic material of bacteria. When infected with phage (viruses), the bacteria are able to integrate parts of the viral foreign DNA into the CRISPR regions of their own DNA (more precisely between the CRISPR regions, where they are being called „spacer“ sequences). The integrated DNA part then functions like a mug shot. As soon as viruses with this DNA attack the bacterium, the bacterial cell recognizes the exogenous DNA and can immediately build up the desired protection. In this way, the bacterial cell becomes immune to the viruses. When joined by the enzyme Cas9 (a so-called „endonuclease“; Cas stands for „CRISPR-associated“) bio scientists Emmanuelle Charpentier and Jennifer Doudna recognized in 2012 that specific DNA targets in the genome can be aimed at and then manipulated. The complex works like a Lego brick finder and scissors at the same time. The researchers populate the CRISPR/Cas9 enzyme complex with a sequence that is exactly complementary to the desired DNA target sequence. The complex then finds the desired target sequence in the DNA and cuts the target sequence exactly there. Any new gene sequence can then be inserted, or an old one can be removed without replacement. This method is therefore also referred to as „word processing in the genome“. While the previous gene editing technique was more like a shotgun that simply aimed shoots at the DNA hoping to hit the desired gen, CRISPR/Cas9 is more like a precision rifle that can be used to remove or insert specifically targeted genetic building blocks. And despite its incomparable potency, the CRISPR technique is so easy to handle that it could be made available to any gene laboratory, and soon perhaps even to high school classes. On Internet platforms like “Indiegogo” or “Origene”, do-it-yourself gene-editing kits are already being sold, with which anyone can perform genome editing on bacteria or yeast cells at home for as little as 25 US dollars. A CRISPR kit with detailed instructions is available for ca. 100 US Dollar.
For this discovery, the two women have now been awarded the Nobel Prize in Chemistry. Finally, one would have to add. What was the Nobel Committee waiting for? CRISPR is the most important bio-medical and gene-technological breakthrough of this century. It could make scenarios like the definitive cure of cancer a reality much faster than even the greatest optimists among genetic engineers thought possible only 10 years ago.
The technology has already been applied in practice on a large scale, especially in the modification of the genetic make-up of industrial plants. By 2015, for example, biologists were already able to use CRISPR to modify the genes of a cultivated mushroom in such a way that pressure points do not turn brown as quickly. In spring 2016 the long-lived mushroom became the first CRISPR product to be approved by the U.S. regulatory authorities. With CRISPR, however, genetic engineering on animals and humans is equally entering a new phase. Soon, interventions in the human genome will no longer be a technical problem. For some medical applications, the technology has already reached the stage of clinical trials. This will affect the treatment of numerous hereditary diseases caused by genetic defects, which have so far been considered incurable, but also of human plagues such as HIV, malaria or even diabetes, cancer, and other age-related diseases.
For many hereditary diseases we know the responsible single gene (for other diseases several genes are involved). One example is „beta thalassemia“, which causes the red blood cell hemoglobin to be produced insufficiently or incorrectly. If father and mother are both carriers of the disease-causing gene, the symptoms are already noticeable in babies: they are very pale and do not develop well. Those affected later report constant headaches and dizziness and that they quickly get out of breath and are tired. Because the hollow spaces in the bones caused by the disease enlarged deformations of the skeleton often occur. All these symptoms could be avoided by replacing the gene whose malfunction leads to the severe red blood cell deficiency. We see that genetic techniques such as CRISPR offer great prospects for relieving humans of much suffering.
But what happens when this technology is applied to embryonic cells, egg or sperm cells? Then not only the individual is manipulated, but all his or her descendants are as well. Scientists today no longer ask on which genes the new method can be used, rather they ask: On which genes should it be used? Should CRISPR maybe not only be used to treat hereditary diseases, but also to genetically influence human characteristics such as eye color, height or even intelligence? CRISPR could ensure that designer babies do not remain a utopia (or dystopia?) any longer. With its help, parents will be able to put together, i.e. design the characteristics of their children – eye color, height, intelligence, body strength and much more – as they desire. In addition, genetically optimized people could soon be cognitively and physically superior to „normal people“. We would enter the era of genetic human breeding.
In May 2015, the scientific journal Nature asked: „Where in the world could the first CRISPR baby be born? With regard to the respective legal situation, the answer was: Japan, China, India, or Argentina. In November 2018, the race was decided: a previously unknown Chinese scientist announced that he had created the first genetically edited humans. He had altered their genome so that they would be immune to HIV for life. For this he had not required more than a moderately equipped laboratory and basic knowledge of genetic engineering. So, it had become clear: We have finally arrived at the age of human experimentation and designer babies.
Like so many other modern technologies CRISPR reveals both the curse and blessing of technical progress. It is a great blessing for the individual, when CRISPR can be used to repair the genome of his „broken“ cells. But what happens if this technology is used to change the healthy human genome, in worst case with consequences for all future generations? Its incomparable potency has long led philosophers, theologians, ethicists and, last but not least, politicians to discuss alongside bioengineers about the consequences of the CRISPR technology in human hands. The Nobel Committee in Stockholm is certainly no exception.