CRISPR Technology is Changing the World
Photo by Yulia Gapeenko
Imagine being able to change the color of your eyes, erase a hereditary disease, or bring back a species from extinction. Today, with CRISPR gene-editing technology, that might not be so impossible. The foundational basis of life is in genes – blueprints that code for everything from eye color to immune function. With emerging advancements in gene editing, scientists can directly change an organism’s trait in minutes.
CRISPR, which stands for clustered regularly interspaced short palindromic repeats, and the CRISPR-associated protein, Cas9, is a naturally occurring immune system defense in bacteria. When a virus infects a bacterium, the bacterium captures the viral DNA and stores it in its own DNA, essentially "remembering" the virus as a genetic memory. The viral DNA is copied into an RNA CRISPR sequence, and a Cas9 protein attaches to the RNA – this complex functions as a lookout. If the virus attacks again, the CRISPR-Cas9 construct recognizes it and cuts the viral DNA, destroying it.
In 2020, professors Emmanuelle Charpentier and Jennifer A. Doudna received the Nobel Prize in Chemistry for implementing the CRISPR immune process into genome editing technology. By designing a custom "guide RNA" that directs the Cas9 enzyme to a specific DNA sequence, scientists can cut and modify genes with incredible precision. This ability to modify genomes with ease has created immense opportunities in science, medicine, agriculture, and for future generations.
To this day, CRISPR is the most efficient gene editing technology among its contenders, TALEN and ZNF. Scientists found that CRISPR-Cas9 was 6 times more efficient than other gene editing techniques. By being able to make mutations to any DNA, CRISPR has already been used to cure various diseases such as hepatitis, parasites, and fungal infections. Furthermore, scientists say CRISPR-Cas9 has the potential to cure more complex diseases, such as cancer, HIV, and heart disease. Furthermore, CRISPR has helped researchers better understand the function of individual genes and the impact of genetic changes on animal species through various tests.
Due to its utility, CRISPR has been widely applied to different industries. CRISPR is prominently utilized in the agricultural industry. A study conducted by multiple Chinese scientists analyzed CRISPR’s impact on crop quality improvement. The scientists found many nutritional benefits after the crops were edited, including higher contents of antioxidants β-carotene, associated with Vitamin A, and GABA, a neurotransmitter that calms the brain. In particular, Cas9-edited rice resulted in higher amounts of β-carotene and GABA. The researchers also confirmed that CRISPR can improve crop palatability, flavor, physical appearance, and more. For example, CRISPR-edited tomatoes and bananas had longer shelf life. Consumers will have more time to use their food before it spoils, minimizing food waste and thus saving money. For manufacturers, CRISPR-edited products maximize supply chain efficiency and allow for streamlined distribution.
Agriculture accounts for around 20% of global greenhouse gas emissions. CRISPR can help reduce emissions in the agricultural sector by boosting plants’ ability to absorb carbon dioxide. Besides crops, livestock are also being edited. With temperatures rising due to climate change, scientists have developed heat and disease-resistant cows. Cows are also notoriously known for releasing methane into the atmosphere, but CRISPR can make genetic changes to reduce this. Advancements in CRISPR also mean less reliance on fertilizers. When broken down, fertilizers release nitrous oxide, a powerful greenhouse gas 300 times more potent than carbon dioxide. Excess fertilizer can also contaminate waterways and cause toxic algae blooms that are harmful to aquatic life. While fertilizers are critical for maintaining soil nutrients, CRISPR may offer ways to reduce dependence on fertilizers by making crops that grow without losing their nutrients, thus eliminating fertilizers’ negative impacts on the environment and supporting the green transition.
While the future of CRISPR is boundless, the understanding of its consequences is deficient. CRISPR is still a very new technology, and scientists have limited answers to its effects on food chains and ecosystems, leading scientists to call for public evaluations of edited plants and animals before they are introduced into the environment. Genetically modified animals could develop into invasive species and create an ecological imbalance. Additionally, modified genes could be transferred easily between species, expediting environmental harm.
One of the most controversial uses of CRISPR is the modification of a human embryo's DNA. In 2015, Chinese scientists used CRISPR-Cas9 to remove a fatal blood disease from human embryos. The mutation was only corrected in one of the embryos, and nontarget effects occurred in other genes. These nontarget effects could continue through each generation, and the number of mutations will likely increase as generations progress. Overall, genome editing in the human germline, such as the one conducted by Chinese scientists, contains high risks for undesired side effects and changes to future generations.
CRISPR may well define the next century of science and medicine. Its potential to edit the code of life itself could allow us to eliminate genetic diseases, transform agriculture, and save our environment. Nevertheless, with such power comes a duty to proceed with caution and care. We must understand the consequences before we alter the blueprint of nature. CRISPR could change our world for the better, but also for the worst: the question isn't simply what we can do, but what we should.
