[Campbell Biology P.537] The text mentions "heterozygote protection" as a mechanism that mai... | Practice Question

The text mentions "heterozygote protection" as a mechanism that maintains a huge pool of alleles. Which of the following best explains how this mechanism contributes to the persistence of potentially harmful recessive alleles in a population?

  • A: Harmful recessive alleles are completely eliminated by natural selection in heterozygous individuals.
  • B: In heterozygous individuals, the harmful effects of the recessive allele are masked by the more favorable dominant allele, allowing the recessive allele to be propagated.
  • C: Heterozygote protection refers to the repair of harmful mutations before they can be expressed in offspring.
  • D: Only homozygous dominant individuals can carry harmful recessive alleles without expressing them.

Explanation

The text explains that "in diploid organisms, however, harmful alleles that are recessive can be hidden from selection. Indeed, a harmful recessive allele can persist for generations by propagation in heterozygous individuals where its harmful effects can be masked by the more favorable dominant allele ." This directly supports option B.