Question

Which of the following is a major factor that can disrupt the Hardy-Weinberg equilibrium?

• A. Genetic drift
• B. Sexual reproduction
• C. Large population size
• D. Random mating

Hint:

The five factors that disrupt Hardy-Weinberg equilibrium are: Mutation, Gene Flow (Migration), Genetic Drift, Natural Selection, and Non-Random Mating.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The Hardy-Weinberg equilibrium states that allele and genotype frequencies in a population remain constant from generation to generation in the absence of evolutionary influences.
Any factor that changes these frequencies disrupts this equilibrium and acts as a driver of evolution.

Step 2: Detailed Explanation:
For a population to remain in Hardy-Weinberg equilibrium, five conditions must be met:
1. Infinite or extremely large population size (prevents sampling errors).
2. Completely random mating (every individual has an equal chance of mating).
3. No mutations (no new alleles are introduced).
4. No gene flow or migration (no individuals enter or leave the population).
5. No natural selection (all genotypes have equal survival and reproductive success).
Let us evaluate the options:
- Genetic drift: This is the random change in allele frequencies in small populations due to chance events.
Because it causes random fluctuations in allele frequencies, it directly disrupts the equilibrium.
- Sexual reproduction: Sexual reproduction redistributes alleles but does not change their overall frequencies on its own, so it maintains the equilibrium.
- Large population size: This prevents genetic drift, helping to maintain the equilibrium.
- Random mating: This ensures that genotypes are distributed predictably, maintaining the equilibrium.
Therefore, only Genetic drift acts as a disruptive factor.

Step 3: Final Answer:
Hence, the correct option is (A).