Question

Which of the following statements are correct about the phenomenon of genetic drift?
A. It occurs in a small population.
B. It leads to the loss of genetic variation within population.
C. It doesn't change the allele frequency randomly.
D. It occurs in a large population.
Choose the most appropriate answer from the options given below:

• A. A and B only
• B. A and C only
• C. B and D only
• D. C and D only

Hint:

Think of genetic drift like flipping a coin. If you flip it 1000 times (large population), you'll get very close to 50% heads. If you only flip it 4 times (small population), it's much more likely you'll get a skewed result like 75% or 100% heads just by chance. That's genetic drift!

Answer 1

The Correct Option is A

Step 1: Genetic Drift Defined:
Genetic drift, an evolutionary mechanism, involves random shifts in allele frequencies within a population's gene pool, driven by chance occurrences.

Step 2: Statement Analysis:
- Statement A: Correct. Genetic drift's impact is strongest in small populations. Random events, like a failure to reproduce, significantly alter allele frequencies in these groups.
- Statement B: Correct. Genetic drift can randomly fix (100% frequency) or eliminate (0% frequency) alleles. Allele loss reduces genetic variation at that specific location. Drift generally reduces a population's genetic diversity over time.
- Statement C: Incorrect. Genetic drift's defining characteristic is its random alteration of allele frequencies. Unlike directional natural selection (which favors adaptive traits), drift is directionless and purely chance-based.
- Statement D: Incorrect. While genetic drift technically occurs in all finite populations, its effects are negligible in large populations. Random fluctuations tend to neutralize each other in large groups, and selection primarily drives allele frequency changes.

Step 3: Conclusion:
Statements A and B accurately describe genetic drift. Statements C and D are inaccurate. Therefore, option (A) is the correct answer.