Question

In a mero-diploid you have one I- and one I+ Repressor gene in the two lac operons. I+ is wild type while I- is a mutant which produces a repressor that doesn’t bind. What would be the functionality of the diploid?

(a) Function normally

(b) Will be non-functional

(c) May or may not function

(d) Will have impaired functioning

This question was posed to me in a national level competition.

I would like to ask this question from Operons : Lac and Ara in section Gene Expression : Transcription Prokaryotes of Cytogenetics

Answer 1

The correct answer is (a) Function normally

Easiest explanation: The set of gene product produced from the wild type I+ loci will be sufficient to induce repression in both the operons. Thus, the system will not be impaired or non-functional.