What term describes random fluctuations in allele frequencies from one generation to the next due to chance?

What term describes random fluctuations in allele frequencies from one generation to the next due to chance?

• A. Gene flow
• B. Mutation
• C. Natural selection
• D. Genetic drift

Answer: (D)

Random fluctuations in allele frequencies from one generation to the next due to chance are genetic drift. This happens especially in small populations because a random sample of gametes may pass on more of one allele by luck alone, causing the overall frequency to shift independent of any advantage or disadvantage. Over time, drift can lead to alleles becoming fixed or lost, and it is especially strong after events that shrink population size (bottlenecks) or when a new population is started by only a few individuals (founder effect). This differs from mutation (which introduces new alleles), natural selection (which favors alleles that improve survival or reproduction), and gene flow (which alters frequencies via migration between populations).

Random fluctuations in allele frequencies from one generation to the next due to chance are genetic drift. This happens especially in small populations because a random sample of gametes may pass on more of one allele by luck alone, causing the overall frequency to shift independent of any advantage or disadvantage. Over time, drift can lead to alleles becoming fixed or lost, and it is especially strong after events that shrink population size (bottlenecks) or when a new population is started by only a few individuals (founder effect). This differs from mutation (which introduces new alleles), natural selection (which favors alleles that improve survival or reproduction), and gene flow (which alters frequencies via migration between populations).