Final answer:
The probability that any given allele will drift to fixation equals the allele's initial frequency in the population, as proved by Sewall Wright in the field of population genetics.
Step-by-step explanation:
Sewall Wright, a key figure in the field of population genetics, demonstrated that the probability that any given allele will drift to fixation in a population is equal to the allele's initial frequency. In the context of genetic drift, fixation refers to the point at which a particular allele becomes the only allele at its locus within a population, effectively reaching 100% frequency.
For example, if an allele has an initial frequency of 0.1 (or 10%) in a population, then the probability of this allele eventually reaching fixation due to drift is also 0.1. The probability of fixation is independent of whether the allele is advantageous, neutral, or even deleterious as long as selection is not acting on it.
It's important to note that the effect of genetic drift on allele frequencies is more pronounced in smaller populations, where chance events can lead to significant changes in allele frequencies from generation to generation.