One of the important topics in the Science and Technology section is “CRISPR Technology”. This is one of the major trending issues nowadays due to major concerns arising due to the introduction of this technology. This issue is of relevance for the exam and there is a high chance of coming off this topic in the exams. Students need to revise the topic on regular basis.
CRISPR Technology :
- CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats and is a reference to the clustered and repeated DNA sequences of bacteria whose natural mechanisms to fight some viral diseases are replicated in this gene-editing tool.
- Editing or altering genetic sequences to eliminate or introduce specific traits in an organism is not a new development. This has been happening for decades, especially in the following areas: Genetically modified crops with specific desirable traits are routinely developed. New genes are introduced or existing genes are suppressed, usually through a process called genetic engineering.
- CRISPR technology is distinct from others. It’s easier and much more accurate. And there is no need to introduce new genes from outside.
- The CRISPR mechanism is often compared to the “cut-copy-paste” or “search-replace” functionality of common computer programs.
- It points out the bad strands of DNA that cause any disorder, removes them, and replaces them with the “right” sequences. And the tools used to do this are not mechanical, but biochemical: specific proteins and RNA molecules.
- This technology replicates the natural defence mechanisms of some bacteria and similarly protects against viral attacks.
Working Mechanism of CRISPR Technology :
- At first, it identifies the specific gene sequences that are causing major issues. Once that’s done, the RNA molecule is programmed to find that sequence on the DNA strand, much like a computer’s “search” function. It then uses a special protein called Cas9, often called ‘genetic scissors, to cut the DNA strand at specific points and remove bad sequences.
- DNA strands that are cut tend to reconnect and repair spontaneously. However, the faulty sequence may be undone if the automatic repair mechanism is allowed to continue. So scientists intervene in the self-repair process by providing the correct sequence of the genetic code that attaches to the broken strand of DNA. It’s like substituting a damaged part of a long zipper with a good part.
- The whole process is programmable and surprisingly efficient, although the possibility of error is not eliminated.
Significance :
- Many diseases and disorders are hereditary. That is, they are caused by unwanted changes or mutations in genes. These include common blood diseases such as sickle cell anemia, eye diseases including color blindness, various types of cancer, diabetes, HIV, and liver and heart disease. Many of these are also hereditary.
- This technology opens up the possibility of permanently curing many of these ailments.
- This also applies to malformations caused by genetic sequence abnormalities such as Stunting or slow growth, speech problems, or inability to stand or walk.
- Also, CRISPR is just a platform. An instrument for editing gene sequences. What and where to edit depends on the case. Therefore, specific solutions must be developed for each disease or disorder to be corrected. Solutions may also be genetically dependent and therefore specific to a particular population or racial group.
- CRISPR-based therapeutic solutions do not come in pill or drug form. Instead, they take a few cells from each patient, edit the gene in the lab, and reinject the patient with the corrected gene.
- Several such solutions have been clinically tested in the last three years. These are primarily associated with blood disorders, diabetes, inherited eye diseases, and some types of cancer.
- In India, the CSIR Institute of Genomics and Integrative Biology has developed her CRISPR-based sickle cell anemia treatment solution and is currently preparing for clinical trials.
- Japan has already approved the commercial cultivation of tomato varieties enhanced by CRISPR-based interventions.
- In India, several research groups are working on the CRISPR-based improvement of various crops such as rice and bananas.
Major Concerns:
1. Designer Babies Issue: In 2018, Chinese researchers announced that they had genetically modified human embryos to prevent HIV infection. This was the first time a ‘designer baby’ was born and caused great concern in the scientific community. Since the changes were made in the embryo itself, newly acquired traits may have been passed on to future generations.
2. It’s not foolproof: While the technique is fairly accurate, it’s not 100% curated and can introduce bugs by making changes to other genes. This can be passed down to posterity.
3. Preventative and Therapeutic Interventions: Preventative interventions to obtain specific traits are not currently intended for use with this technology. However, with therapeutic intervention, genetic changes remain in the individual and are not passed on to offspring.