Question

How many origins of replication are there once the cyclization is carried out by loxP sites?

(a) 1

(b) 2

(c) 3

(d) 4

I have been asked this question in quiz.

The origin of the question is Bacteriophage-Mu and Bacteriophage-Pi in division Other Vector Systems for E of Genetic Engineering

Answer 1

The correct choice is (b) 2

The best I can explain: There are two origins of replication once the cyclization is carried out by loxP sites. One origin of replication is for low copy number and the other can be activated for carrying out a high copy number replication.