Question

Depurination of purine bases results in an apurinic site. Assume a single depurination event occurs in the GC base pair of the sequence below and is not repaired. Then, if two rounds of replication occur, which of the following DNA sequences will exist after two rounds of replication? Remember that when DNA polymerases encounter an apurinic site, most often an A is incorporated into the newly synthesized strand. Assume this is true for the sequence below.
...TACT...

...ATGA...

Select one or more:

a) ...TA_T...
...ATAA...

b) ...TATT...
...ATAA...

c) ...TAAT...
...AT_A...

d) ...TACT...
...ATGA...

e) ...TAGT...
...ATCA...

f) ...TAAT...
...ATTA...

Please explain your work so that I can understand (:

Answer 1

F) ...TAAT...
...ATTA...
Single depurination event occurred in the GC base pair of the sequences so find the C in the 1st sequence & find the G in the 2nd sequence. These are not repaired, so the C & G are eliminated. Then 2 rounds of replication occur in the same spots where the C & G were. Take the letter previous to the empty spots & replicate it in the empty spots. TAAT. ATTA