Scissoring the DNA:CRISPR Technology

Scissoring the DNA

Context:

• Emmanuelle Charpentier of France and Jennifer A Doudna of the USA have been awarded the 2020 Nobel Prize in Chemistry for developing CRISPR/Cas9 genetic scissors, one of gene technology’s sharpest tools.
• It is for the first time a Nobel science prize has gone to a women-only team.

CRISPR Technology:

• The CRISPR (short for Clustered Regularly Interspaced Short Palindromic Repeats) technology for gene-editing was first developed in 2012.
• It makes gene sequencing very easy, simple and extremely efficient providing nearly endless possibilities.
• Editing, or modifying, gene sequences is not new and has been happening for several decades now, particularly in the field of agriculture, where several crops have been genetically modified to provide particular traits.
• It locates the specific area in the genetic sequence which has been diagnosed to be the cause of the problem, cuts it out, and replaces it with a new and correct sequence that no longer causes the problem.

Importance of CRISPR:

• The CRISPR/Cas9 genetic scissors can be used to change the deoxyribonucleic acid (DNA) of animals, plants and microorganisms with extremely high precision.
• The CRISPR/Cas9 tool has already contributed to significant gains in crop resilience, altering their genetic code to better withstand drought and pests.
• This technology has had a revolutionary impact on the life sciences and contributes to new cancer therapies.
• It has the potential of curing inherited diseases.

Application in various treatments:

• The tool has enabled scientists to edit human DNA in a dish and early-stage clinical trials are being attempted to use the tool to treat a few diseases, including inherited disorders/diseases and some types of cancer.
• The CRISPR-Cas9 tool has already contributed to significant gains in crop resilience, altering their genetic code to better withstand drought and pests.
• The technology has also led to innovative cancer treatments and many experts hope that it may help in curing the inherited diseases.
• Genes of plants can be edited to make them withstand pests, or improve their tolerance to drought or temperature.
• Though in 2016 China began the first human clinical trial to treat an aggressive form of lung cancer by introducing cells that contain genes edited using CRISPR-Cas9, the use of the tool has so far been limited to curing genetic diseases in animal models.
• Last year, a Chinese researcher used the tool to modify a particular gene in the embryo to make babies immune to HIV infection, which led to international furore.

Issues:

• Though no guidelines have been drawn up so far, there is a general consensus in the scientific and ethics communities that the gene-editing technique should not be used clinically on embryos.
• The fear of a premature rush of the CRISPR system for therapeutic use still remains.
• Studies have shown that cells edited from CRISPR-Cas9 can lead to cancer.
• The risk of mutations in those cells elsewhere in the genome may increase.
• Although the technique of CRISPR-Cas9 has been used widely to treat many disorders, what diseases or characteristics should be decided through genetic modification is still unknown.
• The problem in this case, potential infection to HIV virus, already had other alternative solutions and treatments.
• What made matters worse was that the gene-editing was probably done without any regulatory permission or oversight.
• Besides, CRISPR technology wasn’t 100 per cent accurate, and it is possible that some other genes could also get altered by mistake.

Way forward

• Unlike in the case of humans, the tool is being extensively used in agriculture. It is being tried out in agriculture primarily to increase plant yield, quality, disease resistance, herbicide resistance and domestication of wild species.
• The gene-editing tool has indeed taken life sciences into a new epoch.