Question

Which of the following doesn’t agree with XIST?

(a) It codes for an mRNA that coats the inactive X chromosome into a bar body

(b) It is the only gene that is active in inactive X chromosome

(c) The embryo cells shows that maternal allele XIST is active over paternal

(d) Inactivation is seen in somatic cells

I have been asked this question by my school teacher while I was bunking the class.

My question is based upon Silencing and Genomic Imprinting in division Regulating Gene Expression in Eukaryotes of Cytogenetics

Answer 1

Correct answer is (c) The embryo cells shows that maternal allele XIST is active over paternal

The best I can explain: XIST allele in case of the embryo doesn’t show any imprinting. Imprinting is seen in case of the extra-embryonic cells.