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GENETIC SCISSORS: TOOL FOR GENOME EDITING

Answer 1:

On 7th of October 2020, the announcement of the 2020 Nobel prize in chemistry was made by the secretary-general of the Royal Swedish Academy of Sciences and it was jointly awarded to Emmanuelle Charpentier, Ph.D., Max Planck unit for the science of pathogens and Jennifer A.Doudna, Ph.D., University of California, Berkeley. The prize was awarded "for the development of a method for genome editing". This also marked the first time that two women have been awarded a nobel prize in science.

The technique that they used is called CRISPR-Cas9 genome editing often referred to as "genetic scissors". Now, in order to find out the inner workings of life, researchers often need to modify genes in cells but this was not an easy thing to do as it used to be extremely time consuming and sometimes even impossible to achieve. But thanks to these "genetic scissors", it is now possible to get this done in the course of a few weeks. So let's try and get some idea about how it works!

CRISPR stands for clustered regularly interspaced short palindromic repeats and Cas9 is the CRISPR associated protein 9. This technique has been adapted from bacteria that use it as a defence mechanism against bacteriophage viruses. When an invading virus injects its DNA into a bacteria, it defends itself by splicing the strips of the virus DNA into its own DNA. The newly formed sequences are called CRISPRs. The bacteria then make RNA copies of this CRISPRs that with the help of Cas9 protein, recognise and cleave virus DNA in the event of a future invasion. 

In 2012, Charpentier and Doudna not only succeeded in recreating the bacteria's genetic scissors in a test tube but were also able to reprogram them. In their natural form, genetic scissors could only recognise virus DNA but Charpentier and Doudna proved that they could be controlled to cut any DNA molecule at any predetermined site. This tool has contributed to many discoveries in the field of basic research and some genetically modified crops have been grown that can withstand pests and drought. This came as a revolution in the field of life sciences and offers a potential tool to cure inherited diseases and much more.

Answer 2:

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