Question

In mice H19 and Igf2 genes are controlled by the same enhancer. Which of the following is true?

(a) The enhancer enhances both the gene on promoter binding

(b) In one chromosome both the genes are expressed and in other they are not

(c) Igf2 shows paternal imprinting, H19 shows maternal imprinting

(d) Both the genes show paternal imprinting

I got this question in an interview for internship.

My doubt stems from Silencing and Genomic Imprinting topic in division Regulating Gene Expression in Eukaryotes of Cytogenetics

Answer 1

Right option is (c) Igf2 shows paternal imprinting, H19 shows maternal imprinting

The best explanation: It is much of a surprise although both the genes can be enhanced by the same enhancer element located downstream of H19 both are not enhanced at once. In maternal gene the H19 is expressed and in paternal gene the Igf2 is expressed.