‘Microsatellite DNA’ is used in the case of which one of the foll

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

Studying the evolutionary relationships among various species of fauna
Stimulating ‘stem cells’ to transform into diverse functional tissues
Promoting clonal propagation of horticultural plants
Assessing the efficacy of drugs by conducting series of drug trials in a population
This question was previously asked in
UPSC IAS – 2023
The correct answer is A) Studying the evolutionary relationships among various species of fauna.
Microsatellite DNA (also known as Short Tandem Repeats or STRs) consists of repeating sequences of a few nucleotides (typically 2-6 bp) found throughout the genome. These regions are highly variable in length among individuals and even among closely related species due to differences in the number of repeat units. This high variability makes microsatellites excellent genetic markers for population genetics studies, genetic diversity analysis, parentage testing, individual identification, and studying evolutionary relationships, particularly among populations within a species or among closely related species where there is sufficient variability.
Options B, C, and D are not primary applications of microsatellite DNA analysis. Stem cell differentiation (B) involves gene expression and signaling pathways. Clonal propagation (C) involves vegetative reproduction techniques, although microsatellites could be used for verifying clonality. Drug efficacy assessment (D) is part of clinical trials and often involves patient response, pharmacokinetics, and sometimes pharmacogenomics (which might use various genetic markers, but microsatellites are not typically the primary tool for drug *efficacy* assessment itself).