Final answer:
Selection against both dominant and recessive alleles can change allele frequencies, but the rate depends on the specific circumstances.
Step-by-step explanation:
The allele frequencies in a population can change due to natural selection. If a dominant allele has a phenotype that allows individuals to have more offspring that survive and reproduce, the frequency of that allele will increase. Similarly, if a recessive allele is disadvantageous and reduces the reproductive success of individuals, its frequency will decrease. Therefore, selection against a dominant allele or selection against a recessive allele can both cause changes in allele frequencies, but the rate at which this occurs depends on the specific circumstances.
For example, if a dominant allele is favored by selection, it can quickly increase in frequency because individuals carrying the allele have a higher reproductive success. In contrast, selection against a recessive allele may take longer to decrease its frequency because it can be hidden in heterozygous individuals, who may still reproduce and pass on the allele. However, if selection against the recessive allele is strong and consistent, it can eventually lead to its elimination from the population.