A mutagenesis screen uncovers two discrete mutations, each for a single gene of a given operon that contains the genes that control a biosynthetic pathway.Which phenomenon would likely be observed in an organism that carries both of these mutations?
A) Partial linkage
B) Complete linkage
C) Epistasis
D) Recessive lethality
E) Complete dominance/recessiveness

Question

Quizplus · Accepted Answer

If both mutations affect different genes in the same operon, it is likely that they will interact with each other in some way. Epistasis refers to a genetic interaction where one gene masks or modifies the effect of another gene. Therefore, the best choice is C, epistasis, as the two mutations may affect the regulation or function of other genes in the operon, leading to an altered phenotype. Partial or complete linkage may occur if the mutations are close together on the same chromosome, but this is not described in the scenario. Recessive lethality or complete dominance/recessiveness would suggest that one mutation is more severe or dominant than the other, which is not specified in the scenario.

A Mutagenesis Screen Uncovers Two Discrete Mutations, Each for a Single