Question

Which of the following features are required to facilitate cloning into a vector?
a. Origin of replication (ori)
b. Selectable marker
c. Cloning site

• A. a and c
• B. b and c
• C. a and b
• D. a, b and c

Answer 1

The correct option is D a, b and c

Origin of replication (ori), selectable marker and cloning site are required to facilitate cloning into a vector.
Ori is a sequence from where replication starts and any piece of DNA to replicate in the host cell needs to be linked to it. It also controls the copy number of the linked DNA. In addition to "ori", the vector requires a selectable marker, which helps in identifying and eliminating non-transformants and selectively permitting the growth of the transformants. In order to link the alien DNA, the vector needs to have very few, preferably single, recognition sites for the commonly used restriction enzymes. The ligation of alien DNA is carried out at a restriction site present in one of the two antibiotic resistance genes.