Genetic drift operates only in

Options

A. Larger populations
B. Mendelian populations
C. Island populations
D. Smaller populations.

Answer

**Step-by-Step Solution:**

1. **Understanding Genetic Drift**:
- Genetic drift is defined as a random change in the allele frequency within a population. It is particularly significant in small populations where chance events can lead to substantial changes in genetic makeup over generations.

2. **Identifying Population Size**:
- Genetic drift is most pronounced in smaller populations. In larger populations, the effect of random changes is diluted because the larger number of individuals tends to stabilize allele frequencies.

3. **Evaluating the Options**:
- The question provides several options regarding where genetic drift operates:
- A. Larger population
- B. Mendelian population
- C. Island population
- D. Smaller population
- Analyzing each option:
- **A. Larger population**: Incorrect, as genetic drift is not significant in large populations.
- **B. Mendelian population**: Incorrect, as Mendelian populations are typically large and follow predictable inheritance patterns.
- **C. Island population**: Incorrect, as island populations can vary in size, and genetic drift is not limited to them.
- **D. Smaller population**: Correct, as genetic drift is primarily observed in smaller populations due to the higher impact of random events.

4. **Conclusion**:
- Based on the analysis, the correct answer is **D. Smaller population**. Genetic drift operates primarily in small populations where random changes can significantly affect allele frequencies.