How does genetic drift manifest over several generations?

• A. By speeding up mutation rates
• B. By stabilizing gene frequencies
• C. By causing random allele frequency shifts
• D. By enhancing adaptive traits

Answer: (C)

Genetic drift manifests over several generations primarily through causing random allele frequency shifts in a population. This phenomenon occurs due to the random nature of allele inheritance from one generation to the next, particularly in small populations where chance events can have a more pronounced impact on the gene pool. For instance, if certain alleles happen to be passed on more often by mere chance—regardless of whether they carry any advantage or disadvantage—their frequencies within the population can increase or decrease unpredictably over time.

This process can lead to the fixation or loss of alleles, contributing to evolutionary changes that are not directly related to natural selection, which typically favors traits that enhance survival or reproduction. Over many generations, genetic drift can result in significant divergence between populations, particularly when they are isolated from one another or subject to different environmental conditions, ultimately influencing the genetic diversity and evolution of those populations.