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Lindsey Barnett

What is CRISPR?

Updated: Nov 25

By Lindsey Barnett

November 2024


CRISPR, an acronym for Clustered Regularly Interspaced Short Palindromic Repeats, is a revolutionary tool in genetic engineering that allows scientists to precisely edit DNA. Originally discovered as part of bacteria's immune defense system against viruses, CRISPR has been adapted into a versatile technology with transformative applications in medicine, agriculture, and biology.


The foundation of CRISPR technology lies in its natural origins. Bacteria use CRISPR as a mechanism to fend off viral infections. When a virus invades a bacterial cell, the bacteria incorporate fragments of the viral DNA into their own genome, storing it in the CRISPR sequence. This sequence acts as a genetic memory bank. When the same virus attacks again, the bacteria produce RNA molecules from the CRISPR sequence, guiding an associated protein, Cas (short for CRISPR-associated protein), to the matching viral DNA. Cas proteins, such as Cas9, function like molecular scissors, cutting the DNA and neutralizing the virus (Jinek et al., 2012).


Building on this discovery, researchers developed a tool to target specific genes in virtually any organism. By designing custom RNA guides, scientists can direct the Cas9 protein to a chosen sequence in an organism’s DNA. Once the DNA is cut, cells repair the damage using one of two mechanisms: non-homologous end joining, which often introduces mutations that deactivate the target gene, or homology-directed repair, where a specific DNA template is provided to introduce desired changes (Doudna & Charpentier, 2014).


The implications of CRISPR are far-reaching. In medicine, CRISPR is being used to develop treatments for genetic disorders such as Huntington's disease. In December of 2023, the FDA approved the first CRISPR-based gene editing therapy for sickle cell disease. By correcting mutations at their source, researchers hope to provide permanent cures. CRISPR also holds promise in combating infectious diseases, such as using the technology to engineer mosquitoes that are resistant to malaria (Gantz et al., 2015). Additionally, its applications extend to oncology, where CRISPR is being explored to create personalized cancer therapies.


Agriculture is another area where CRISPR has transformative potential. Scientists are using it to engineer crops that are more resistant to pests, diseases, and environmental stresses like drought. For instance, CRISPR has been employed to enhance the nutritional content of crops such as rice and wheat, addressing global food security challenges (Zhang et al., 2018).


Despite its promise, CRISPR raises ethical and technical concerns. Off-target effects, where unintended sections of DNA are edited, pose significant risks. Moreover, the potential to edit human embryos has sparked ethical debates about designer babies and unintended societal consequences. International guidelines are being developed to ensure that CRISPR is used responsibly (National Academies of Sciences, Engineering, and Medicine, 2017).


In conclusion, CRISPR technology represents a groundbreaking leap in genetic science. By harnessing a bacterial defense system, researchers have developed a tool with the potential to revolutionize medicine, agriculture, and beyond. As scientists continue to refine CRISPR and address its ethical implications, the technology stands as one of the most powerful innovations of the 21st century.



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