Gene-Editing [UPSC Notes for GS III]

Gene-Editing, also known as Genome editing is a way of making specific changes to the DNA of a cell or organism.

Context of the Article – Recently, a Chinese scientist has claimed to have created the world’s first genetically edited babies using CRISPR-Cas9 technology, in a potentially ground-breaking and controversial medical first.

Gene–Editing, related advantages, and its concerns are often seen in the news, and hence the topic holds relevance for the UPSC Mains.

These UPSC Notes on Gene–Editing are aligned with the UPSC Syllabusand aspirants should prepare this topic for General Studies Paper III.

Aspirants would find this topic very helpful while preparing for the IAS Exam.

Gene–Editing

Background

  • He Jiankui Chinese researcher shocked the scientific community in 2018 after announcing he had
    successfully altered the genes of twin girls born in November to prevent them from contracting HIV.
  • He had “privately” organised a project team that included foreign staff and used “technology of
    uncertain safety and effectiveness” for illegal human embryo gene-editing, investigators said.
  • But such gene-editing work is banned in most countries, including China.

Cutting-and-pasting DNA (CRISPR-CAS9)

  1. CRISPR-CAS9 is a technology that allows scientists to essentially cut-and-paste DNA, raising hope of
    genetic fixes for disease. However, there are also concerns about its safety and ethics.
  2. CRISPR is a dynamic, versatile tool that allows us to target nearly any genomic location and
    potentially repair broken genes. It can remove, add or alter specific DNA sequences in the genome of
    higher organisms.

How does Gene-editing work?

  1. Unusual but repeated DNA structures that scientists had been observing for some time were given a
    name. This name assigned was “Clustered regularly interspaced short palindromic repeats” or
    CRISPR.
  2. In 2012, scientists discovered that CRISPR is a key part of the “immune system”. For instance, when a virus enters a bacterium, it fights back by cutting up the virus’s DNA.
  3. This kills the virus but the bacterium stores some of the DNA.
  4. The next time there is an invasion, the bacterium produces an enzyme called Cas9 which matches
    the stored fingerprints with that of the invaders.
  5. If it matches, Cas9 can snip the invading DNA.

The CRISPR-Cas9 gene-editing tool thus has two components. They are:

  1. a short RNA sequence that can bind to a specific target of the DNA and
  2. the Cas9 enzyme which acts as molecular scissors to cut the DNA.

To edit a gene of interest, the short RNA sequence that perfectly matches with the DNA sequence that has to
be edited is introduced. Once it binds to the DNA, the Cas9 enzyme cuts the DNA at the targeted location where the RNA sequence is bound.

Once the DNA is cut, the natural DNA repair mechanism is utilized to add or remove genetic material or make changes to the DNA.

What are the possible advantages of Gene editing?

  1. CRISPR could be used to modify disease-causing genes in embryos brought to term, removing the
    faulty script from the genetic code of that person’s future descendants as well. Genome editing
    (Gene editing) could potentially decrease, or even eliminate, the incidence of many serious genetic
    diseases, reducing human suffering worldwide.
  2. It might also be possible to install genes that offer lifelong protection against infection.
  3. CRISPR May Prove Useful in De-Extinction Efforts. For example, Researchers are using the powerful gene-editing tool to recreate the woolly mammoth.
  4. CRISPR Could Create New, Healthier Foods: In agricultural crops, Crispr has the potential to impact
    yield, disease resistance, taste, and other traits. Few experiments have been done. If successful it
    can help us to eradicate the problem of hunger and malnutrition.

What are the cons of Gene editing?

  1. Making irreversible changes to every cell in the bodies of future children and all their descendants
    would constitute extraordinarily risky human experimentation.
  2. There are issues including off-target mutations (unintentional edits to the genome), persistent
    editing effects, genetic mechanisms in embryonic and fetal development, and longer-term health
    and safety consequences.
  3. Altering one gene could have unforeseen and widespread effects on other parts of the genome,
    which would then be passed down to future generations.
  4. Many consider genome alterations to be unethical, advocating that nature should be left to run its
    own course.
  5. Few argue that after permitting human germline gene editing for any reason would likely lead to its
    ignorance of the regulatory limits, to the emergence of market-based eugenics that would exacerbate already existing discrimination, inequality, and conflict.
  6. It will become a tool for selecting desired characteristics such as intelligence and attractiveness.
  7. It can also be used to eliminate dangerous species of pests and few experiments are being carried
    out on mosquitoes but eliminating a species, even one that doesn’t appear to have much ecological
    value could upset the careful balance of ecosystems. That could have disastrous consequences, such as disrupting the food web or increasing the risk that diseases like malaria could be spread by
    different species entirely.
Precision-guided Sterile Insect Technique (pgSIT):

  • Developed by researchers at the University of California
  • It uses a CRISPR-based approach to engineer deployable mosquitoes that can suppress populations.
  • The pgSIT-derived eggs are introduced into targeted populations, emerge into only adult sterile males.
  • pgSIT uses CRISPR to simultaneously disrupt key genes that control female viability and male fertility in pest species.

Current scientific advancements show that CRISPR is not only an extremely versatile technology, it’s proving to be precise and increasingly safe to use. But a lot of progress still has to be made; we are only beginning to see the full potential of genome-editing tools like CRISPR-Cas9. Technological and ethical hurdles still stand between us and a future in which we feed the planet with engineered food, eliminate genetic disorders, or bring extinct animal species back to life.

Gene–Editing (UPSC Notes – GS 3): Download PDF Here

Aspirants can check BYJU’S UPSC Notes page for free GS1, GS2, and GS 3 notes.

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Frequently Asked Question – Gene Editing Or Genome Editing

Q.1. What are Genes?

Ans. A gene is the basic physical and functional unit of heredity. Genes are made up of DNA. Some genes act as instructions to make molecules called proteins. However, many genes do not code for proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases.

Q.2. What is Genome Editing?

Ans. Genome editing (also called gene editing) is a group of technologies that enables scientists to change the DNA of many organisms, including plants, bacteria, and animals.

Q.3. What is DNA?

Ans. DNA stands for Deoxyribonucleic acid. It is a complex molecule that contains all of the information necessary to build and maintain an organism. All living things have DNA within their cells.

Q.4. What is CRISPR-Cas9?

Ans. CRISPR-Cas9 is a unique technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding or altering sections of the DNA sequence. CRISPRs are specialized stretches of DNA.

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