Question

If you want to recover many copies of the target DNA, you will choose a vector __________________.

• A. Which does not have origin of replication
• B. Which has antibiotic resistance gene
• C. Whose origin supports high copy number
• D. Which has only one restriction site

Answer 1

Answer: (C)

Whose origin supports high copy number

Vectors that have a high number per cell will have a high copy number of their genome within the bacterial cell. If we link an alien piece of DNA with vector, we can multiply its number equal to the copy number of the vector. Any piece of DNA when linked to the $ori$ sequence, can be made to replicate within the host cells. This property of $ori$ is used to make many copies of the linked DNA. If we want to obtain many copies of the target DNA, then it should be cloned in such a vector whose $ori$ supports high copy number.