UPSC Prelims 2023 Q70: Science & Technology – Biotechnology & Genetics
'Microsatellite DNA' is used in the case of which one of the following?
- (a) Studying the evolutionary relationships among various species of fauna
- (b) Stimulating 'stem cells' to transform into diverse functional tissues
- (c) Promoting clonal propagation of horticultural plants
- (d) Assessing the efficacy of drugs by conducting series of drug trials in a population
Answer: (a) Studying the evolutionary relationships among various species of fauna
Explanation
Microsatellite DNA (Short Tandem Repeats, STRs)
| Feature | Fact |
|---|---|
| What it is | Short DNA motifs of 1–6 base pairs repeated many times (e.g. CACACA...) |
| Variation | The number of repeats differs widely between individuals and populations |
| Why useful | Highly polymorphic, so it acts as a genetic fingerprint |
Uses of microsatellites:
| Field | Use |
|---|---|
| Evolution and population genetics | Evolutionary relationships among species and populations |
| Wildlife conservation | Tracking tiger and elephant populations; detecting poaching |
| Forensics | DNA fingerprinting in crime and paternity cases |
| Plant breeding | Marker-assisted selection |
India's CCMB (Hyderabad) and its LaCONES lab use microsatellites for wildlife forensics.
Answer: (a) Studying the evolutionary relationships among various species of fauna.
Why each option is right or wrong
- (a) CORRECT. Microsatellites are genetic markers used to study evolutionary relationships and population genetics.
- (b) Incorrect. Turning stem cells into tissues uses growth factors, not microsatellite markers.
- (c) Incorrect. Clonal propagation of plants uses tissue culture, not microsatellites.
- (d) Incorrect. Drug efficacy is tested through clinical trials, not by microsatellite analysis.
Key point
Microsatellites (STRs) = short repeated DNA motifs; used for evolutionary studies, wildlife forensics and DNA fingerprinting.
Remember
Microsatellite DNA is used to study evolutionary relationships among species.
Common mistakes
- Confusing microsatellite DNA with space satellites because of the name.
- Thinking microsatellites are genes; they are mostly non-coding repeats.
- Choosing tissue culture because both are biotechnology topics.
Exam tip
Repeats vary → fingerprint. Anything about relationships, identity or ancestry points to microsatellites.
Sources
- NCERT Class XII — Biology, Ch 5 (Molecular Basis of Inheritance — DNA fingerprinting)
- CCMB — Laboratory for the Conservation of Endangered Species (LaCONES)