WHAT IS CRISPR?

Author: Riya Kathpalia

From: New Delhi, India

As Charles Darwin suggested in his book called ‘the Origin of Species’, our existence is a result of the transition due to random genetic changes causing variations to occur. This is the reason why everyone has different genotype and phenotype, also the variations are a result of Error in DNA replication mechanism. Mutations occur due to the presence of new alleles (alternative form of the gene) into the population of organism, thus causing drastic

variation which decreases the chances of survival. The mutations can rarely be

helpful.

What if there was some kind of mutated disease (DNA based) spread, is there a solution to stop its spread?

The answer to the question is yes, this is where the role of CLUSTERED REGULARLY INTERSPACED SHORT PALINDROMIC REPEATS (CRISPR) technology comes, it helps in correcting genetic defects, treating and preventing the spread of diseases and improving crops. So, it holds immense potential as therapeutic tools fix disease causing mutations at the level of DNA. Indeed, there have been different ways of gene editing except CRISPR but this

technology benefits the scientists by making gene editing incredibly easier and cheaper.

How does CRISPR technology work?

In bacteria and archaea, there are spaces which are capable of changing the sequence of the DNA with the help of the enzyme called Cas9 and guide RNA. A perfect analogy is that they work like hand with scissors. In these organisms, these spaces help in defending themselves against the viruses. Genome editing involves changing those sequences, thereby changing the

messages. This can be done by inserting a cut or break in the DNA and tricking a cell's natural DNA repair mechanisms into introducing the changes one wants. CRISPR-Cas9 provides a means to do so. Researchers create a small piece of RNA with a short "guide" sequence that attaches (binds) to a specific target sequence of DNA in a genome. The guide RNA also binds with the Cas9 protein for the working.

Role of CRISPR in medicine

Alterations in over 3000 human genes are known to be associated with diseases. Monogenic disorders, such as Huntington’s disease, cystic fibrosis, thalassemia, and sickle cell anemia, are caused by single-gene mutations while multifactorial diseases such as cancer and diabetes resulted from an interplay between numerous genetic mutations and environmental conditions. Unfortunately, a majority of diseases lack effective treatment strategies; hence, genomic medicine offers a vast potential as an effective therapeutic strategy to combat human

Disease. As techniques improve to attempt to make precise, targeted modifications to genome sequences, genetic medicine proves to have extensive promise as a therapeutic intervention against human diseases.

Controversies again CRISPR

Just by the happening of a small mistake during the use of this technology, a mice were given human lung cancer. Concluding, the implications of the use of the technology can be good or bad depending upon the use. We can do a lot in the now as well as in the future, but every organism and every cell are different, so we must think about unexpected side effects and consider the ethics of changing genes.

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About the Author: Riya Kathpalia

Riya is a sophomore in high school. She is interested in medicine and biology and wants to pursue a career in the respective subjects. She hopes that the epistemology of the evolving discoveries in the field of Science reaches everyone out there!

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