Twenty-Five Years Ago, When Oshima and Colleagues Discovered That a Mutation

Multiple Choice

Twenty-five years ago, when Oshima and colleagues discovered that a mutation in the GAL4 gene led to the inability to synthesize all five enzymes required for galactose catabolism (breakdown) , they couldn't be blamed for wanting to apply a bacterial model to explain this finding. What they expected, but did not find, was ________.

A) that all five genes constitute an operon
B) five widely separated genes, each containing a GAL4-binding site in its regulatory region
C) that chromatin decondensation played an important role in regulating the genes of galactose catabolism
D) that transcription is important in regulating the genes of galactose catabolism