THE EMERGING GENE EDITING TOOL: CRISPR-Cas9

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CRISPR CAS9 

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The biggest biotechnology discovery of the century is CRISPR CAS9. This tool has already stepped in to revolutionize the biotechnology. Scientists have hacked this tool to study diseases and discover drugs at a faster rate.

The famous application of CRISPR being the modification of the human genome, along with which it brings the promise to combat many genetic diseases.

We are very much aware of genetics and from past many years, the research is being carried out in the respective field. Since genetics revolve around genetic material which is DNA, and changes in DNA plays a vital role in the study.

In order to understand the function of the gene, scientists believe in changing the gene itself, either in a cell line or a whole organism, by doing so it helps them to study the effect of that change in a gene and which easily monitor its function. To bring change in gene i.e mutation, geneticists in the past used chemicals or radiations irrespective of the fact that it was unknown where in the genome the mutation would occur. Later on, scientists started targetting gene to bring about changes in specific places in the genome.

So what is CRISPR-cas9?
It is a genetic tool which helps in the editing of DNA. CRISPR has already created a buzz and fuss in the science and technology world. CRISPR-cas 9 system is now considered to be the fastest, cheapest and more precise technique for gene editing. It promises to have vast potential in a future application.
So how it was recognized?
In 1987 clustered regularly interspaced short palindromic repeats (CRISPR) was first noticed in bacteria. This sequence was mysterious for many years but later in 2000, it was suggested from clues that it was part of the antivirus defense system of bacteria.

What was the idea behind this technology?
Scientists observed that some bacteria have default gene editing system like CRISPR- cas 9 and they use this system to defend themselves from invading of pathogens like viruses analogy to the immune system. Using crispr technique bacteria cut out parts of the virus DNA keeping a bit of it which helps for identification and defend next time if it attacks. Scientists adapted to this system which they would use in other cells of animals which also include mice and humans.

Let us know how does it work?
The whole crispr technology work on two important component

1. An enzyme which is known as Cas 9
Cas9 is a piece of molecule scissor that cut two strands of DNA at a specific location in the genome. This act as a mark using which again the DNA bits can be joined or removed.

2. The piece of RNA also known as guide RNA or gRNA
It consists of pre-designed small fragments of RNA sequence about 20 bases long in RNA platform. This RNA platform binds to DNA and the pre-designed sequence guides cas9 to the right part of the genome which ensures cas9 enzyme cuts at the right point in the genome.

How guide RNA is designed so that it binds to a specific sequence of DNA?
The guide RNA is designed in such a way that its bases are complementary to the bases of the target DNA sequence in the genome. So at least theoretically the guide RNA will only bind to the target sequence and no other region of the genome.
Now the cas9 go after the guide RNA to the same location in DNA sequence and makes a cut across both the strands of DNA. Now when the cell realizes there is a cut in its genome, it tries to repair it. This natural DNA repair machinery is observed and hence scientist introduced changes to one or more genes in the genome of a cell of interest.

Application of CRISPR technology
Theoretically, CRISPR could modify the DNA of any living being for a different application. In the pharma industry, it is basically targeted in drug discovery. Gene editing tool is becoming very famous in research labs to modify the genome of organisms from bacteria and insects to mice, pigs, and monkeys. Looking at its vast application it seems the resources are being utilized to use crispr tool to engineer human DNA. By WHO it is estimated that over 10,000 diseases are caused by a mutation in a single human genome. In such cases, crispr brings hope to cure all of them by repairing the genetic error of the patient.

What about the safety of crispr in editing human DNA ?
This is the most critical question now, though there are investments and talk about CRISPR with every discovery comes the ethical and moral values. in a recent study, it showed that cas9 protein is naturally found in bacteria that infect humans and the immune system of humans is already primed to attack it. Hence any immune reaction against CRISPR will render is useless and along with which it will also create severe side effects.

Gene therapy was first tested in the ’90s and failed pathetically leading to biotech death of 18year old Jesse Gelsinger. Suppose even if crispr proves to be safe in human, then the question arises is how ethical it is to modify human genome? if we consider curing of genetic disease with this technology, then fine but the point is to what extent?
Where should the line be drawn?

In order to modify human feature based on the will is far ahead in the future, but it’s our responsibility to start thinking about how the technology should be utilized and regulated right now. Also, guidelines should be drawn specifying when it is allowed and when it has to be banned.

Right now many of the scientists and activists agree that editing in the germline, through which children will inherit should be left out as for now.

let us know your point of view on this technology, do comment below.

 

 

Drafted by Nagama Nadaf
 A technophile who is crazy about technology and passionate about blogging. 
I care by sharing recent advancements in technology and try to reach out to the minds of people
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