Week 8: What is CRISPR?

A “CRISPR” stands for Clustered Regularly Interspaced Short Palindromic Repeats, which are the hallmark of a bacterial defense system that forms the basis for CRISPR-Cas9 genome editing technology. In the field of genome engineering, the term “CRISPR” or “CRISPR-Cas9” is often used loosely to refer to the various CRISPR-Cas9 and -CPF1 systems that can be programmed to target specific stretches of genetic code and to edit DNA at precise locations. 


With these systems, researchers can permanently modify genes in living cells and organisms and, with time, may make it possible to correct mutations at precise locations in the human genome in order to treat genetic causes of disease. Other systems are now available, that target DNA provide alternate avenues for use, and with unique have been leveraged for sensitive diagnostic tools.

CRISPRs were first discovered in archaea by Francisco Mojica, a scientist at the University of Alicante in Spain. He proposed that CRISPRs serve as part of the bacterial immune system, defending against invading viruses. They consist of repeating sequences of genetic code, that are interrupted by “spacer” sequences , which are the remnants of genetic code from past invaders.


CRISPR “spacer” sequences are transcribed into short RNA sequences capable of guiding the system to matching sequences of DNA. When the target DNA is found, Cas9 – one of the enzymes produced by the CRISPR system – binds to the DNA and cuts it, shutting the targeted gene off


CRISPR genome editing allows scientists to quickly create cell and animal models, which researchers can use to accelerate research into diseases such as cancer and mental illness. To help encourage more research in this, Feng Zhang and his team have trained thousands of researchers in the use of CRISPR genome editing technology.


CohenFeb, Jon, et al. “CRISPR.” Science, 26 Oct. 2018, www.sciencemag.org/topic/crispr.

“Questions and Answers about CRISPR.” Broad Institute, 4 Aug. 2018, www.broadinstitute.org/what-broad/areas-focus/project-spotlight/questions-and-answers-about-crispr.

Biolabs, New England. “CRISPR/Cas9 & Targeted Genome Editing: New Era in Molecular Biology.” New England Biolabs: Reagents for the Life Sciences Industry, www.neb.com/tools-and-resources/feature-articles/crispr-cas9-and-targeted-genome-editing-a-new-era-in-molecular-biology.

“Full Stack Genome Engineering.” Synthego, www.synthego.com/learn/crispr.

“CRISPR Guide.” Addgene, www.addgene.org/crispr/guide/.

Picture Sources:

“CRISPR: Implications for Materials Science.” Cambridge Core, www.cambridge.org/core/journals/mrs-bulletin/news/crispr-implications-for-materials-science.

“Do CRISPR Risks Outweigh Rewards?” GEN, 5 Nov. 2018, www.genengnews.com/magazine/328/do-crispr-risks-outweigh-rewards/.

“CRISPR/Cas9 and Genome Editing in Drosophila.” Journal of Genetics and Genomics, Elsevier, 18 Dec. 2013, www.sciencedirect.com/science/article/pii/S1673852713002130.