Q. What is the application of Somatic Cell Nuclear Transfer Technology? (UPSC Prelims 2017)
Answer:
Reproductive cloning of animals
Notes: The correct answer is
[C] Reproductive cloning of animals.
Somatic Cell Nuclear Transfer (SCNT) is the laboratory strategy used to create a viable embryo from a body cell and an egg cell. It is the core technology behind the creation of the famous sheep,
Dolly, in 1996.How SCNT WorksThe process involves two different cells:
- The Somatic Cell: A normal body cell (like a skin or mammary gland cell) is taken from the animal to be cloned. Its nucleus, which contains the DNA, is extracted.
- The Enucleated Egg Cell: An egg cell is taken from a donor, and its own nucleus is removed (enucleated), leaving an empty shell that still contains the necessary "machinery" to start a life.
- The Transfer: The nucleus of the somatic cell is inserted into the empty egg cell.
- Activation: An electric shock or chemical treatment "reprograms" the egg to behave as if it has been fertilized. It begins to divide and form an embryo, which is then implanted into a surrogate mother.
Applications of SCNTWhile reproductive cloning is the most famous application, the technology has broader scientific uses:
- Reproductive Cloning: Creating an exact genetic copy of an animal (used in livestock for superior traits or for preserving endangered species).
- Therapeutic Cloning: Creating cloned embryos to harvest stem cells. These cells can potentially be used to grow replacement tissues or organs that the patient’s body won't reject.
- Transgenic Animals: Producing animals that can secrete useful proteins or medicines in their milk (Pharming).
Why the other options are incorrect:
- [A] Biolarvicides: These are usually produced using bacteria like Bacillus thuringiensis (Bt) or through fermentation processes, not nuclear transfer.
- [B] Biodegradable Plastics: These are manufactured using polymers derived from plants (like corn starch) or through bacterial fermentation (like PHAs).
- [D] Disease-free Organisms: While cloning can replicate a healthy animal, "disease-free" status is usually achieved through genetic engineering (like CRISPR/Cas9) or rigorous selective breeding and quarantine, rather than SCNT alone.