Answer: Gene
Explanation:
Mutation can be defined as the change in the single base pair of the DNA. Each and every trait inside an eukaryotic organism body is controlled by the help of the gene.
Pie bald is also a trait controlled by the genes in the body. Pie bald can be defined as a pattern of unpigmented spots on the pigmented background of scale, feather and hair.
Example: A pie bald black and white dog is a black dog with white spots on it.
