Question

Each of the mutants listed below this paragraph has a different mutant form of the gene encoding protein X. Each mutant gene contains one or more nucleotide insertions (+) or deletions (−) of the type caused by acridine dyes. Assume that all the mutations are located very near the beginning of the gene for protein X. In each case, indicate with an "OK" if you would expect the mutant protein to be nearly normal and with a "Not OK" if you would expect it to be obviously abnormal.
-/-/+/-/- , +/-/+ , +/-/+/- , +/+/-/+ , -/+ , - , -/-/-/-/-/- , +/+/+ , -/-

Answer 1

It should be taken into consideration the presence of frameshift mutations. Frameshift mutation, due to addition or deletion of a base, results in the change of reading frame and consequently in changed protein. But it is known that 3 nucleotides on mRNA code for the specific amino acid. If the number of inserted or deleted nucleotides is 3, it will result in the absence of only 1 amino acid which is not expected to drastically change protein sequence.
Knowing all this, it can be concluded the following:

-/-/+/-/- OK - Due to 4 deletions and 1 insertion, effectively only 3 nucleotides are missing.
+/-/+ Not OK - Due to 1 deletion and 2 insertions, effectively only 1 nucleotide is added leading to the frameshift mutation.
+/-/+/- OK - Due to 2 deletions and 2 insertions, a number of nucleotides remain the same.
+/+/-/+ Not OK - Due to 1 deletion and 3 insertions, effectively only 2 nucleotides are added and the frameshift mutation occurs.
-/+ OK - Due 1 deletion and 1 insertion, a number of nucleotides remain the same.
- Not OK - Due to 1 deletion, the frameshift mutation occurs.
-/-/-/-/-/- OK - Due to 6 deletions, it will be deleted 2 amino acids and the protein will be nearly normal.
+/+/+ OK - Due to 3 insertions, 1 amino acid will be added in excess.
-/- Not OK - Due to 2 deletions, the frameshift mutation occurs.