Question

Which of the following is not true about the Notch gene in Drosophila?

(a) It causes a special indentation of the wing margin

(b) It is expressed in heterozygous form

(c) Notch is lethal in homozygous form

(d) Notch is recessive to Facet

This question was addressed to me during an online interview.

My question is taken from Chromosomal Abnormalities : Deletion topic in chapter Chromosomal Basis of Inheritance of Cytogenetics

Answer 1

The correct option is (d) Notch is recessive to Facet

For explanation I would say: Facet is expressed only in absence of Notch gene by deletion, thus it is pseudo dominant and recessive to the notch gene. Other options are true, notch is also lethal in hemizygous condition.