Question

Genetic drift is of significance in:

• A. Large populations
• B. Randomly mating populations
• C. Stable populations
• D. Small populations

Hint:

Genetic Drift = Random change in allele frequency due to chance.
Always most pronounced and significant in small populations!
Large populations are protected from genetic drift according to Hardy-Weinberg equilibrium principles.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks to identify the population size condition under which evolutiory genetic drift exerts a major, statistically significant influence on allele frequencies.

Step 2: Key Formula or Approach:
Genetic drift represents random fluctuations in gene allele frequencies from generation to generation due to sampling errors in gamete sampling.
The variance in allele frequency change ($\sigma_{\Delta p}^2$) per generation is inversely proportiol to population size ($N_e$): \[ \sigma_{\Delta p}^2 = \frac{p(1-p)}{2N_e} \]

Step 3: Detailed Explation:

• Mechanism of Genetic Drift: In finite populations, by random chance alone, certain individuals may produce more offspring or survive better regardless of their adaptative fitness.

• Impact of Population Size:
• In large populations, random sampling errors average out, making allele frequencies stable unless acted upon by tural selection, mutation, or migration.

• In small populations, random sampling error is large ($2N_e$ in the denomitor is small), leading to rapid, unpredictable fluctuations in allele frequencies.

• Consequences in Small Populations: Genetic drift can quickly lead to the random fixation of one allele ($p=1$) and complete loss of altertive alleles ($p=0$), reducing genetic diversity over time.

• Classic Phenome: Founder Effect and Population Bottleneck represent extreme scerios of genetic drift operating in small isolated populations.

Step 4: Fil Answer:
Genetic drift is of paramount evolutiory significance in small populations.