Genomic imprinting affects gene expression in a development context. Which statement best describes imprinting?

Genomic imprinting affects gene expression in a development context. Which statement best describes imprinting?

• A. Imprinting is parent-of-origin-specific gene expression due to differential methylation; it affects growth and development; abnormal imprinting can cause disorders.
• B. Imprinting refers to silencing of genes randomly in somatic cells.
• C. Imprinting occurs only in plants.
• D. Imprinting is when genes are expressed from both parents equally.

Answer: (A)

Imprinting is a gene expression pattern where the expression of a gene depends on which parent donated the allele. This occurs because epigenetic marks, especially DNA methylation, are set in the gametes and silence one allele while allowing expression from the other. The result is monoallelic expression of the gene, which affects gene dosage during development and growth. If imprinting is disrupted or incorrect marks are maintained, it can lead to developmental disorders such as Prader-Will and Angelman syndromes, illustrating the impact of imprinting on development. The other statements don't fit because imprinting is not random silencing in somatic cells, is not limited to plants, and does not involve equal expression from both parents.

Imprinting is a gene expression pattern where the expression of a gene depends on which parent donated the allele. This occurs because epigenetic marks, especially DNA methylation, are set in the gametes and silence one allele while allowing expression from the other. The result is monoallelic expression of the gene, which affects gene dosage during development and growth. If imprinting is disrupted or incorrect marks are maintained, it can lead to developmental disorders such as Prader-Will and Angelman syndromes, illustrating the impact of imprinting on development. The other statements don't fit because imprinting is not random silencing in somatic cells, is not limited to plants, and does not involve equal expression from both parents.