[Campbell Biology P.546] Suppose two plant populations exchange pollen and seeds. In one pop... | Practice Question

Suppose two plant populations exchange pollen and seeds. In one population, individuals of genotype AA are most common 9,000 AA, 900 Aa, 100 aa , while the opposite is true in the other population 100 AA, 900 Aa, 9,000 aa . If neither allele has a selective advantage, what will happen over time to the allele and genotype frequencies of these populations?

  • A: The allele and genotype frequencies in both populations will remain constant due to the absence of selective advantage.
  • B: The allele frequencies will diverge further, leading to increased genetic differentiation between the populations.
  • C: The allele and genotype frequencies in both populations will become more similar over time, eventually equilibrating due to gene flow.
  • D: The less common alleles (aa in the first, AA in the second) will be eliminated from each population due to random drift.

Explanation

Gene flow, the exchange of alleles between populations, acts to reduce genetic differences between them. Even in the absence of selective advantage, if populations are exchanging genetic material, their allele and genotype frequencies will tend to converge and become more uniform over time. The large population numbers given suggest that genetic drift random elimination of alleles, more impactful in small populations would be less significant than the consistent gene flow.