Shown below are the results of a series of coinfections using T4 rII- strains similar to those employed by Benzer.Each strain contains a different deletion mutation.Ability to produce wild-type progeny phage is indicated by (+), and (o) indicates no wild-type progeny. Indicate the order that is most consistent with these data.
A)CADBE
B)ACBDE
C)BADCE
D)BEDCA
E)CEADB

Question

Shown below are the results of a series of coinfections using T4 rII- strains similar to those employed by Benzer.Each strain contains a different deletion mutation.Ability to produce wild-type progeny phage is indicated by (+), and (o) indicates no wild-type progeny.   Indicate the order that is most consistent with these data.
A)CADBE 
B)ACBDE 
C)BADCE 
D)BEDCA 
E)CEADB

Quizplus · Accepted Answer

The data show that each mutant strain is unable to produce wild-type progeny phage with one of the other mutants but can produce wild-type progeny with the remaining mutants. This indicates that each mutant contains a deletion mutation in a different gene necessary for wild-type phage production. 
Thus, the order of mutations can be inferred from the data as follows: 
- Mutant C cannot produce wild-type progeny with mutant A 
- Mutant A cannot produce wild-type progeny with mutant D 
- Mutant D cannot produce wild-type progeny with mutant C 
- Mutant B cannot produce wild-type progeny with mutants C or E 
Based on this, the most consistent order of mutations is BADCE, making choice C the correct answer.

Shown Below Are the Results of a Series of Coinfections