As the world rejoices and celebrates yet another magnificent scientific discovery by honoring the scientists behind it with the most coveted prize – The Nobel, we bring to you a series of articles that would help you understand the importance of these discoveries to the common man.
Today, we focus on the discovery which led Drs. Emmanuelle Charpentier and Jennifer Doudna to win the Nobel Prize in Chemistry.
They received this honor for their discovery of a way to manipulate DNA using molecular scissors– a technique called CRISPR (pronounced as ‘crisper’). The idea for this stemmed from their analysis of bacterial immunity. When certain bacteria get attacked by viruses, they nick out a portion of the viral DNA and embed it into their genome as a memory. When the virus attacks the bacteria again, these embedded DNA sequences kickstart a mechanism wherein a bacterial protein targets the same DNA sequence in the virus and cleaves it thereby rendering the virus inactive.
Drs. Charpentier and Doudna while studying this looked at it not just as a study of bacterial immunity against viruses but found it as a means to use this technique to cleave DNA of their liking thereby providing them with ‘molecular scissors’. Let us get into the finer details.
Before we begin, a few basics that you ought to know:
- The genetic paradigm of life is ‘DNA makes RNA which then makes proteins’.
- DNA is made up of specific stretches of ‘bases’ called Adenine (A), Guanine (G), Cytosine (C) and Thymine (T) (replaced by Uracil (U) in RNA). Each of these bases can specifically pair with one another (A with T/U and C with G).
Suppose there is a stretch of DNA that one wishes to alter, then a ‘guide’ RNA is made with the target sequence and this leads the Cas protein (the molecular scissor) to the site and enables the cutting of the DNA at that particular point. When a cut is made thus, the cell’s repair machinery kicks in and tries to reseal the bond and in doing so errors are introduced in the DNA sequence (which could be random or guided to the introduction of a base we intend to) leading to turning on or off of genes, correcting mutations etc. This is what CRISPR is all about.
The question is where can this technique be used? The answer is very vast – right from agricultural biotechnology for 
developing resistance to pests and water stress in crops to treating pets and even human beings at some point in time.
That’s a summary of the work that fetched Drs. Charpentier and Doudna the Nobel Prize. If you wish to understand more and also to know what CRISPR stands for (intentionally not mentioned in this article), click on these links and widen your knowledge in this field of science.
http://www.crisprtx.com/gene-editing/crispr-cas9
https://www.livescience.com/58790-crispr-explained.html
https://www.newscientist.com/term/what-is-crispr/
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