Evolutionary Forces in Small Populations

Let’s examine the main options:

• Inbreeding:
  Inbreeding increases homozygosity and can expose deleterious alleles, changing genotype frequencies. It can indirectly affect allele frequencies, especially when coupled with selection or drift.

• Genetic Drift:
  Genetic drift is the random fluctuation of allele frequencies due to chance events. Its impact is strongest in small populations, where alleles can quickly become fixed or lost, dramatically altering genetic diversity.

• Outbreeding:
  Outbreeding introduces new genetic material into a population, increasing heterozygosity and potentially altering allele frequencies, especially in small populations.

• Random Mating:
  Random mating, by definition, means individuals pair by chance, not by genotype or phenotype. This process does not change allele frequencies; it only shuffles existing alleles into new genotypes. Random mating maintains Hardy-Weinberg equilibrium and preserves current allele frequencies unless acted upon by other forces.

Which Has the Least Impact?

Among these options, random mating has the least impact on allele frequencies in small populations. It does not introduce new alleles, does not favor any allele over another, and does not cause random fluctuations in allele frequency. Its primary effect is to maintain genetic stability, not to drive evolutionary change.

Correct Answer

(2) Random mating