Question

Which of the following is an example of genomic imprinting in humans? Which of the following is an example of genomic imprinting in humans? A random pattern of autosomal allele inactivation is observed. In some allele pairs, only the paternal sourced allele is expressed, and in others, only the maternal sourced allele is expressed. The maternal and paternal alleles of a gene pair are both expressed. Human males have only one Y-chromosome and one X-chromosome. One of the two X-chromosomes in females is randomly expressed and the other is repressed.

Answer 1

In some allele pairs, only the paternal sourced allele is expressed, and in others, only the maternal sourced allele is expressed.

Step-by-step explanation:

Genomic imprinting is an epigenetic phenomenon where alleles are differentially expressed depending on their parental origin (for example, paternally expressed when it is inherited from the father). Genomic imprinting is controlled by epigenetic modifications (for example, DNA methylation, histone acetylation, etc) which works together to preferentially activate the expression of the allele inherited from one parent and simultaneously silence or “​imprint” the expression of the allele inherited from the other parent. In humans, an example of genomic imprinting is the case of the insulin-like growth factor 2 (Igf2) gene, which is maternally imprinted (repressed), thereby this gene is only expressed from the paternal allele.