Answer:
Genomic imprinting.
Explanation:
Genomic imprinting may be defined as the epigenetic phenomena that shows the different expression of the gene depending on the parent origin. The genomic imprinting has been found in plants, fungi and animal.
The deletion from the father chromosome results in Prader–Willi syndrome. The deletion of chromosome from mother results in Angelman syndrome. Here, the expression of the genes depend on the whether it has been inherited from the father and mother.
Thus, the answer is genomic imprinting.