Final answer:
Genetic variants arise through mutation, which is a random change in DNA, and represent new genetic information in a population. While natural selection can influence which mutations become more common or disappear, it does not create new genetic variations.
Step-by-step explanation:
All genetic variants ultimately arise through mutation, which is option (e). Mutation is a change in the DNA sequence that can lead to new genetic variation within a population. This process is indeed random and is the ultimate source of new alleles. However, once a mutation occurs, it may be acted upon by other evolutionary forces like natural selection, genetic drift, or gene flow. For instance, natural selection can favor mutations that provide a selective advantage, thereby increasing their frequency in a population. Conversely, other mutations might be detrimental and thus selected against, resulting in their removal from the gene pool over time.
Natural selection and mutation are often confused, but it's important to distinguish between them. Mutation is the only one listed that actually creates new genetic information. Natural selection works on existing variability in a population to favor traits that improve chances of survival and reproduction. Therefore, while natural selection is a critical mechanism of evolution, it does not create genetic variants; it only shapes their distribution within the population.