Question

Which two of the following processes can result in a decline in heterozygosity in populations? I) Inbreeding; II) Genetic drift; III) Mutation; IV) Random mating

• A. I and II
• B. II and III
• C. I and III
• D. II and IV

Hint:

To analyze heterozygosity: 1. Inbreeding and genetic drift reduce heterozygosity by increasing homozygosity and allele fixation.
2. Mutation and random mating do not decrease heterozygosity directly.
3. Population size greatly influences the effects of genetic drift.

Answer 1

The Correct Option is A

Step 1: Define processes affecting heterozygosity. Inbreeding (I): Inbreeding occurs when closely related individuals mate. This increases homozygosity and reduces heterozygosity in the population. Genetic drift (II): Genetic drift is a random process that leads to the fixation or loss of alleles, reducing heterozygosity over time, particularly in small populations. Mutation (III): Mutation introduces new genetic variation, which typically increases heterozygosity rather than reducing it. Random mating (IV): Random mating does not alter heterozygosity directly, as it maintains the Hardy–Weinberg equilibrium in the absence of other evolutionary forces. Step 2: Evaluate the options. Option I and II (A): Correct. Both inbreeding and genetic drift reduce heterozygosity in populations. Option II and III (B): Incorrect. Genetic drift reduces heterozygosity, but mutation increases it. Option I and III (C): Incorrect. Inbreeding reduces heterozygosity, but mutation increases it. Option II and IV (D): Incorrect. Genetic drift reduces heterozygosity, but random mating does not alter it.