When b1 is neutral or mildly deleterious, provided it is initially in gametic disequilibrium (i. e. co- inherited) with a1 and selection favoring a1 is much stronger than the rate of recombination between loci a and b. Regular inbreeding does not change allele frequencies in the long run but does alter genotype frequencies from hardy-weinberg proportions; genetic drift changes allele frequencies across generations in the long run but genotypes are in hardy-weinberg proportions. What statement best describes the action of genetic drift. Genetic drift occurs when allelic variation is neutral; it can change allele frequencies in the short run and will ultimately drive one allele to fixation. The probability of a particular allele"s becoming fixed from any point in time onward is equal to its relative frequency at that point in time, not its relative frequency before or after that point in time. In a population of 100 cockroaches, a student discovers one individual who is bright blue.