Final answer:
When the active copy of a gene is deleted and the other copy remains silent due to imprinting, it can result in diseases such as Prader-Willi syndrome and Angelman syndrome.
Step-by-step explanation:
When the active copy of a gene is deleted and the other copy remains silent due to imprinting, it can result in diseases. Examples of such diseases include Prader-Willi syndrome and Angelman syndrome. Prader-Willi syndrome occurs when the active copy of genes on chromosome 15 from the father is deleted, leading to a range of symptoms including low muscle tone, obesity, and intellectual disabilities. Angelman syndrome, on the other hand, occurs when the active copy of genes on chromosome 15 from the mother is deleted and is characterized by developmental delays, seizures, and frequent laughter or happy demeanor.