**Core Concept**
The phenomenon of differential expression of the same gene depending on the parent of origin is a complex genetic process that involves epigenetic modifications and gene regulation. This concept is closely related to genomic imprinting, where certain genes are expressed differently based on whether they are inherited from the mother or the father.

**Why the Correct Answer is Right**
Imprinting of genes is determined by the parent of origin, and this is achieved through epigenetic modifications such as DNA methylation and histone modification. These modifications are typically established during gametogenesis and are maintained throughout the life of the organism. For example, the insulin-like growth factor 2 (IGF2) gene is imprinted, meaning that it is only expressed from the paternal allele, while the maternal allele is silenced. This is achieved through the action of the H19 gene, which encodes a non-coding RNA that recruits enzymes to silence the maternal allele of IGF2.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the concept of differential gene expression based on parent of origin.
* **Option B:** This option may refer to a different genetic phenomenon, such as X-chromosome inactivation, which is a process that occurs in females to silence one of the two X chromosomes.
* **Option D:** This option is not a recognized term in genetics and is not relevant to the concept of differential gene expression based on parent of origin.

**Clinical Pearl / High-Yield Fact**
Genomic imprinting is an important mechanism that can affect gene expression and has been implicated in various diseases, including cancer and neurological disorders. Understanding the concept of genomic imprinting is crucial for identifying and treating these conditions.

**Correct Answer: C. Imprinting**