This is the only phenomenon active in a model that uses the expression negative natural log of one minus theta to estimate Reynolds’s distance. Michael Lynch’s barrier hypothesis is partially named after this phenomenon, which is modeled backwards in time to determine coalescence events. The null hypothesis for the McDonald–Kreitman test states that this phenomenon predominates, in accordance with Kimura’s neutral theory. (10[1])This phenomenon explains (-5[1])why the time to fixation for an allele is proportional to effective population size in the Wright–Fisher model for it. Pioneer species are subject intensely to the founder effect, (10[1])a form of this phenomenon (10[1])that also (-5[1])manifests (10[1])during (10[1])population bottlenecks. (10[1])For 10 points, name this phenomenon where allele distributions change randomly. ■END■ (10[2])