Final answer:
Mutations in homeotic genes can lead to significant phenotypic changes, such as incorrect placement of body parts, as seen with the Antennapedia mutation in fruit flies. Epistatic interactions in genes can also affect phenotypes, as illustrated by the variety of fur colors in mice.
Step-by-step explanation:
When homeotic genes mutate, they can cause dramatic phenotypic changes, such as body parts developing in the wrong place or changes in the shape and structure of organs. One classic example is the Antennapedia mutation in Drosophila (fruit flies), where legs grow in the place of antennae due to the expanded distribution of the gene product caused by the mutation.
Similarly, mutations that affect epistasis can also lead to unexpected phenotypic ratios, such as the case with mouse fur color, where the interaction of two different genes can result in a variety of colors, such as agouti, black, or albino, depending on the combination of alleles an individual mouse inherits.