The scissors of the award-winning women
The Nobel Prize in Chemistry, awarded annually by the Swedish Academy of Sciences, was awarded in 2020 to two scientists: French microbiologist Emmanuelle Charpentier, from the Max Planck Centre, based in Germany, and American chemist Jennifer Doudna, from the University of California, Berkeley, for the development of the CRISPR/Cas9 method for editing the human genome.
It is interesting to note that of the 112 Nobel Prizes in Chemistry awarded since 1901, only seven have been awarded to women. A French and an American woman have become the sixth and seventh women to win the Nobel Prize in Chemistry, the 56th and 57th women to win the Nobel Prize overall, and the first time the prize has been shared by two women. In 2015, both received the Princess of Asturias Award for Scientific and Technical Research, which sometimes serves as a precursor to the Nobel Prize.
Dubbed “genetic scissors,” “molecular scissors,” and “genetic cut-and-paste,” CRISPR/Cas9 is a biological tool that allows for genome modification with unprecedented precision and in a much simpler and cheaper way than any previous method. Like a word processor, CRISPR/Cas9 can manipulate the genome through a mechanism that “cuts and pastes” DNA sequences; cutting a gene that causes a disease and replacing it with one that does not cause that problem.
In 2012, Jennifer Doudna and Emmanuelle Charpentier published a groundbreaking article in the journal Science , titled "A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity ." In it, they proposed the use of a kind of "molecular scissors" capable of cutting, pasting, and editing DNA. This technology had a revolutionary impact on the world of medicine , as it allowed, among other things, the development of cancer therapies and even raised the possibility of definitively curing hereditary diseases. Before the invention of this technique, gene editing was usually a slow, difficult, and sometimes impossible process. However, the use of the CRISPR-Cas9 technique allows scientists to change "the code of life" in just a few weeks.
The discovery of CRISPR/Cas9 was inspired by a process found in some of the oldest organisms on the planet: archaea and bacteria. Archaea, for example, use CRISPR/Cas9 as a defense mechanism against viruses. When archaea are infected by a virus, the CRISPR/Cas9 complex cuts and eliminates it. What happened in 2012 was that this natural tool was adapted for use as a biotechnological tool. CRISPR (which stands for "Clustered Regularly Interspaced Short Palindromic Repeats") is a system of genetic elements that includes enzymes called Cas, which function like molecular scissors that cut and modify DNA with a high degree of precision and specificity. The technique has revolutionized laboratory trials seeking cures for diseases as varied as genetic disorders, cancer, viral diseases, and Alzheimer's. It is also being applied in both plant and animal production.
How does this technique work? RNA, which encodes the Cas9 protein, is injected into the cell along with a kind of guide that tells Cas9 where to cut the DNA strand. The sequences to be inserted are also introduced into the cell, because when Cas9 breaks the DNA, the cell's machinery kicks in to repair it, using the inserted sequences to replace the cut ones. Although these are no longer sequences like those found in bacteria, but rather genetic guides designed in the laboratory, they are still called CRISPR.
Since Charpentier and Doudna discovered the CRISPR/Cas9 gene-editing tool in 2012, its use has skyrocketed. It has enabled the development of crops resistant to mold, pests, and drought. It is being used in clinical trials of new cancer therapies, and it is hoped that it will soon contribute to curing hereditary diseases.
Although it is very precise, there is a limitation: cutting the DNA strand can produce unwanted errors and create new mutations in the genome. Therefore, its use for modifying human embryos, eggs, and sperm has not yet been approved. Nor has it been approved for modifying animals.
What was once considered a dream, utopia, or science fiction, we now know is possible thanks to these genetic scissors that brought the future to the present…this is more than the 21st century.
Ramona Ávila Núñez, Ph.D.
References
- Martin Jinek, Krzysztof Chylinsk, Ines Fonfara, Michael Hauer, Jennifer A. Doudna, Emmanuelle Charpentier. A programmable dual- RNA-guided DNA endonuclease in adaptive bacterial immunity . Science . 2012. 337. 816-821.
- 2020 Nobel Prize in Chemistry awarded to the inventors of "genetic scissors." NATIONAL GEOGRAPHIC. Available at: https://www.nationalgeographic.com.es/ciencia/premio-nobel-quimica-2020-para-inventoras-tijeras-geneticas_15961