Define CRISPR: What Is It and How Is It Used in Drug Discovery

The latest tools in the Drug Discovery toolbox can sometimes be difficult to decipher, especially with new forms of genetic engineering popping up often. The potential for confusion and mixing up terms makes it all the more important to define CRISPR and understand how this popular technology can be used in Drug Discovery. 

The pharmaceutical industry is closely connected to modern science, helping drive the development of new tools, technologies, and medicines that describe and treat diseases. The motivation to move science forward falls on the backdrop of needing new treatments as soon as possible and marketing them faster than the competition.

In order to meet the high demands of modern Drug Discovery, most scientists and researchers rely on gene silencing, reverse genetics, and other forms of genetic engineering like Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and Transcription Activator-Like Effector Nuclease (TALENs).

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Define CRISPR: What Is It and How Is It Used in Drug Discovery

CRISPR Definition

CRISPR is a relatively recent discovery and is based on DNA found in bacteria used to identify and fight viruses. In practice, CRISPR is a tool that allows scientists to easily edit genes and DNA. With the Cas9 variant becoming readily and easily available, CRISPR has quickly become one of the most popular forms of genetic engineering used in Drug Discovery.

CRISPR works like a pair of microscopic genetic scissors, allowing for controlled cuts in strands of DNA.

While genetic engineering as a concept in the scientific community has been around for several decades, it was less accessible and more expensive in both time and money before CRISPR. Replacing long processes and complex machinery with a simple pair of genetic scissors has opened the floodgates for new research into diseases and medicines.

Different Types of CRISPR

Since its original discovery, CRISPR has gone from an incredible phenomenon found in nature in 2007 to a programmable tool used by scientists. There are many different proteins that allow for the precise cuts and edits associated with CRISPR. Cas9 was the first and is the most common version of genome editing technology, but there are other varieties worth mentioning and understanding in order to properly define CRISPR.


Originating from Streptococcus pyogenes, this variety of CRISPR uses the Cas9 protein to edit DNA. As the first and most widely used CRISPR protein effector, Cas9 benefits from a strong background of established cases and well-documented functionality. Cas9 works by efficiently breaking strands of DNA at specific points. However, the ease of use and swift action have the drawback of not always being the most precise.

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Originating from Francisella novicida, this variety of CRISPR differs from Cas9 in the way it cuts strands of DNA. Rather than going for a blunt cleave, Cas12 is known for its staggering cuts and only requiring CRISPR RNA. In general, Cas12 is seen as a useful tool for making multiple edits on a single strand of DNA, precisely targeting even the smallest amounts of very specific gene combinations.


Originating from Leptotrichia shahii, Cas13 stands out for its unique property of only targeting RNA instead of DNA. In other words, rather than cleaving double-stranded DNA or making tiny cuts to DNA, Cas13 cuts single-stranded RNA. A significant detail that helps exemplify the advantages of CRISPR Cas13 can be seen in how only targeting RNA allows for modifying gene expression without editing any genes or otherwise altering the genome. 

Making Use of CRISPR with Zebrafish

In order to fully take advantage of the latest genetic engineering tools like CRISPR Cas9, Cas12, and Cas13, scientists and researchers need to have access to model organisms as well. Testing potential treatments and looking into how new diseases could affect humans requires building a better understanding of how the molecules affect both specific strands of DNA and the biological system as a whole.

CRISPR remains an established and important reality for the pharmaceutical industry.

Zebrafish are a great example of an alternative animal model that has a proven track record with genome editing, including CRISPR, allowing scientists to observe how abstract traits in DNA manifest themselves in living organisms. CRISPR and animal models like Zebrafish are helping pharmaceutical companies move science forward, providing the tools and data for all the tests and assays needed to develop new treatments, drugs, and vaccines.

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