Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If a researcher moves the promoter for the lac operon to the region between the beta galactosidase (lacZ) gene and the permease (lacY) gene, which of the following results would be most likely?
A) The three genes of the lac operon will be expressed normally.
B) RNA polymerase will no longer transcribe permease.
C) The operon will still transcribe the lacZ and lacY genes, but the mRNA will not be translated.
D) Beta galactosidase will not be produced.

Question

Quizplus · Accepted Answer

Moving the promoter for the lac operon between the lacZ and lacY genes would disrupt the normal transcription of beta galactosidase, which requires a promoter upstream of the lacZ gene. Without a functional promoter, transcription of lacZ will be impaired, and beta galactosidase will not be produced. The other genes in the operon (permease, regulator) might still be expressed normally or to some degree, but the lack of lacZ expression would likely limit the metabolic activity of the bacterium in lactose-containing conditions.

Suppose an Experimenter Becomes Proficient with a Technique That Allows