How does genetic drift relate to variation, change, and mutation?
Drift refers to change resulting from stochastic (chance) processes, such as the “Mendelian lottery”. Drift can happen only where variation exists. Drift reduces (eventually eliminates) neutral variation within a population, such that some neutral alleles are eliminated and others are fixed. New neutral alleles (new variation) are introduced by mutation. Of those new variants, some (most) are eliminated by drift, some (few) are fixed. Over time, neutral change accumulates by drift. (Both allele-elimination and allele-fixation are examples of change.) When change by drift occurs in two or more related populations, those populations will diverge. This divergence can occur simply because of by variation among the populations in which alleles are fixed/eliminated. But this divergence is increased by the introduction of new mutant alleles into each population, some of which will drift to fixation. (more) Return to question list.
