I never did this before, but it looks like fun so let's give it a try.
We are told the following:
A. Each amino acid substitution resulted from a single base substitution.
B. Mutant A has the codon UGG.
Let's start with Mutant A:
We know its codon sequence is
UGG. Hence, the normal codon sequence will be only one base pair different. The only possibility that codes for serine and fits this rule is
UCG.
Next, let's figure out Mutant B:
We are told that Mutant B codes for leucine. By looking at the protein translation chart, we know there are only 6 possibilities:
UUA UUG CUU CUC CUA CUGHowever, we also know that Mutant B must be only one base substitution away from the normal protein and mutant A. The only codon sequence that fits is:
UUGLet's figure out Mutant E next:
We are told that Mutant E codes for valine. There are 4 possibilities from the protein translation chart:
GUU GUC GUA GUG. Of these, only a single possibility is one base substitution away from Mutant B. That would be
GUG.
Let's figure out Mutant D next:
Mutant D codes for glycine. The 4 possibilities are:
GGU GGG GGA GGC. Of these, only a single possibility is one base substitution away from Mutant E. That would be
GGG.
Finally, let's figure out Mutant C:
Mutant C codes for arginine. There are two possibilities that are one base substitution away from Mutant A and Mutant D. Those are
CGG and
AGG. This is where I get "stuck" between choosing one mutation over the other without more information.
Hope this is correct.