Question: Assume you have made a collection of mutant fruit flies that aredefective in various aspects of DNA repair. You test each mutantfor its hypersensitivity to three DNA-damaging agents: sunlight,methylnitrosourea (which cause alkation of guanosine),and nitrous acid (which causes deamination of cytosineand conversion to uracil which lead to a mutation and the necessity to repair during replication). each type of damage will lead to the activation of the three different repair pathways including base excision repair, nucleotide excision repair, and mismatch repair.The results are summarized in the figure below, where a”yes” indicates that the mutant is more sensitive (thereby defective in repair )than a normal fly and blanks indicate normal sensitivity.

………………………Sunlight| methyl nitrosurea| nitrous acid |
Dracula Yes | | |
Faust | | Yes | |
Mole | Yes | | |
Mr. Self-destruct | Yes | Yes | Yes |
Marguerite | l | Yes |
A.
Which of the mutants is most likely to be defective in theDNA repair polymerase and why?

B.
for the remaining mutants not described in A identify which one of the three repair pathways listed above might be affected?