Question

Alkaline Phosphatase is used at times and the vector is treated with it. Choose the incorrect statement.

(a) It removes 5’ terminal phosphate group from nucleic acids

(b) The 5’ phosphate group is required for the ligation to take place

(c) Two phosphate bonds should be formed for the complete ligation to take place

(d) The ligation between vector and insert won’t take place

The question was posed to me in final exam.

This question is from Modifications in Cloning Methods, Linkers,  Adaptors and Cassettes topic in division Simple Cloning of Genetic Engineering

Answer 1

The correct option is (d) The ligation between vector and insert won’t take place

For explanation I would say: Alkaline phosphatase is used at times and the vector is treated with it. It is responsible for the removal of phosphatase group from the 5’ end. This group is required for the ligation reaction to take place and at each end two phosphates are required. But as the phosphate groups are removed from the vector, its relegation is not possible now. But as the insert is still having a phosphate group, one strand will form the bond and the ligation reaction will take place.