Final answer:
The mechanism responsible for genomic imprinting is methylation. Methylation involves the addition of a methyl group to the DNA molecule within specific regions of genes. This can lead to the silencing of genes and differential expression depending on the parent of origin.
Step-by-step explanation:
The mechanism responsible for genomic imprinting is methylation.
Methylation refers to the addition of a methyl group (-CH3) to the DNA molecule, specifically within regions called CpG islands. These CpG islands are found in the promoter regions of genes. Methylation can lead to the silencing of genes, resulting in differential expression depending on whether the gene comes from the mother or father.
For example, if a gene is methylated in the egg or sperm cells of one parent, it will be inherited in a silenced state to the offspring. This is known as genomic imprinting and is an epigenetic phenomenon that can affect gene expression.