OPSC OAS 2020 PrelimsScience & TechnologyQuestion 20
Solved previous year question from the OPSC OAS/OCS 2020 Preliminary Examination (General Studies), with the official answer key and a detailed explanation.
Question
Change in the base sequence within a gene is called:
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Answer & Explanation
Correct answer: (A) Mutation
- A change in the base sequence within a gene is called a Mutation. Mutations are permanent alterations in the DNA nucleotide sequence that make up a gene. These changes can affect a single base pair (point mutation) or involve larger segments of DNA.
The other options are incorrect
| Option | Definition |
|---|---|
| (B) Cloning | Production of genetically identical copies of an organism, cell, or DNA molecule. Does not involve changing base sequences. Example — Dolly the sheep (first cloned mammal, 1996). |
| (C) Fusion | Combining two different cells or organisms to form a hybrid. Examples include cell fusion (somatic hybridisation), protoplast fusion in plants, nuclear fusion in physics. Does not refer to base sequence changes. |
| (D) Breeding | Controlled mating of organisms to produce offspring with desired traits. Includes selective breeding, crossbreeding, hybridisation. It works with existing genetic variation, not direct base sequence changes. |
