It would be difficult to say....
More complex enzyme as in instead of yeast? I would say that they would still get the same result - One gene one protein (later changed to one gene one poly peptide).
The mutation at a coding region of DNA would deprive the organisms' ability to produce the protein that region codes for.
However, in more complicated organisms, there are significantly more regions where DNA does not code for protein. (any biologists verify this?) This may complicate the experiment.
