Genetic Scissors | Noble Prize in Chemistry 2020
‘Genetic scissors’ and rewriting the code of life
WHY IN NEWS:
How does a method for genome editing developed by two women scientists help in tackling diseases?
The discovery of “one of gene technology’s sharpest tools:the CRISPR/Cas9 genetic scissors” will lead to the emergence of novel biological applications by making it easier to edit genes.
SYLLABUS COVERED: GS 1 : 3 : Awards : Science and Technology
For PRELIMS we have briefly explained CAS9 technology here . Take out your Prelims book and note this down ! It is important .
For MAINS ; this question has already been asked in Mains ! But still go through Benefits and the Misuses . Let us dive in !
WHAT IS CRISPR/CAS9?
- Much like Microsoft (MS) Word , the CRISPR/Cas9 system allows for adding, altering and deleting the genomic code in living beings.
- This is much like file names used to store various documents we write in MS Word.
- The COVID-19 pandemic has brought to the fore the importance of ‘memory cells’.
- Memory cells can quickly produce relevant antibodies to neutralise a repeat infection by a virus.
- Similarly, the CRISPR are a part of bacteria’s immunological systems that help them in recognising threatening viruses.
- When they sense a lurking virus, the bacteria produce customised RNA, which is necessary to translate DNA into protein, gleaned from the CRISPR libraries.
- This also contains Cas (CRISPR-associated) genes that are used to produce enzymes such as Cas-9.
- These enzymes — the Cas-9 being a particularly popular one — can be used to chop the DNA of the virus and destroy them.
HOW CAN THIS BE USED TO EDIT GENOMES?
- Using the tool, researchers can change the DNA of animals, plants and microorganisms with precision.
- While studying this, she discovered a previously unknown molecule, tracrRNA.
- The same year, she initiated a collaboration with biochemist Jennifer Doudna, now a professor at the University of California, Berkeley.
- Together, they succeeded in recreating the bacteria’s genetic scissors in a test tube .
- They also simplified the scissors molecular components so they were easier to use.
- In a significant experiment, they reprogrammed the genetic scissors.
- In their natural form, the scissors recognise DNA from viruses.
SOURCES : GOOGLE SITES
- Other genome editing systems like TALENs and Zinc-Finger Nucleases can do similar jobs.
- But several users consider the Charpentier-Doudna tool more adaptable and easier to use.
- It is less than a decade since this system gained wide research and commercial interest.
- Coupled with the availability of genome sequences for a growing number of organisms.
- The technology allows researchers to find out what genes do, characteristics , special attributes etc.
- Then they can be tested in combinations with other mutations too.
- The commercial potential of the system is so compelling that within years of its development.
- There was a battle over the ownership of the intellectual property rights of the CRISPR/Cas9 .
- This involved the University of California and the Massachusetts Institute of Technology’s Broad Institute.
- A person with hereditary blindness became the first to have a CRISPR/Cas-9-based therapy directly injected into her body.
- Gene-editing with beta thalassemia and sickle cell disease would no longer require blood transfusions .
- CRISPR is in the battle against the COVID-19 and has tied up with GlaxoSmithKline to develop a test to detect infections.
- The name has been chosen after the fictional Bengali detective, based on the CRISPR/Cas9 system.
- There are commercial CRISPR-based home kits that allow amateur researchers to develop their own biotechnology applications, triggering a sub-culture called ‘bio-hacking’.
- The most controversial application of CRISPR/Cas9 was in 2018.
- Chinese researcher He Jiankui announced that he had used it to create ‘gene-edited twins’ Lula and Nana via in-vitro fertilisation.
- The HIV uses the CCR5 to infect cells and the modified gene would shut the door against such an entry.
- He was widely condemned and sentenced to three years in jail, and stripped of his position too.
- It is not known how these mutations are going to play out over the children’s lifetimes .
- The CRISPR/Cas-9 system allows a democratic usage in labs across the world to tinker with genomes.
- It still has not reached the level of precision required to be sure that it does not cause unintentional side effects.
- Research is already underway for using proteins that are smaller and more efficient than Cas-9.
- This “may make the dream of curing inherited diseases come true”.
SOURCES:THE HINDU | Genetic Scissors | Noble Prize in Chemistry 2020 | UPSC