Question 35 from UPSC CSE 2023 - S&T

Question

Microsatellite DNA is used in the case of which one of the following?

IASCODEX · Accepted Answer

Correct Option: A. Studying the evolutionary relationships among various species of fauna

Strategy: - Identify microsatellite DNA as highly polymorphic, repeating sections used for assessing genetic relationships, variability, and evolutionary patterns.
- Eliminate options unrelated to DNA marker technology, such as cell stimulation, plant propagation, or drug trials.
- Select the choice that directly links microsatellites with studying evolutionary relationships among fauna, as it aligns with their established utility.

Key Info: Microsatellite DNA consists of short tandem repeats (STRs) that are 1-6 base motifs repeated in non-coding DNA regions. They display high levels of polymorphism due to variation in repeat number among individuals or species, making them powerful genetic markers.

Applications include:
-   **Population genetics**: Used to study genetic diversity, gene flow, and breeding patterns among animal or human populations.
-   **Phylogenetic analysis**: Helps trace lineage, evolutionary relationships, and divergence among species of fauna and flora.
-   **Forensics and paternity testing**: Due to their high variability, microsatellites are standard in DNA fingerprinting.
-   **Conservation biology**: Identification of population bottlenecks, inbreeding, and management of endangered species.

Microsatellites are not directly used to stimulate stem cells, propagate plants clonally, or assess drug efficacy in populations. They are pivotal in molecular ecology and evolution.

Key examples include studies on genetic structure of tiger populations in India, tracing ancestry in human populations, or differentiating between closely related animal species.

IASCODEX · Answer

Option B: Stimulating 'stem cells' to transform into diverse functional tissues

IASCODEX · Answer

Option C: Promoting clonal propagation of horticultural plants

IASCODEX · Answer

Option D: Assessing the efficacy of drugs by conducting a series of drug trials in a population