Assertion: Origin of replication(Ori) is an essential part of a vector.
Reason:Ori is responsible for initiating replication.

Both A and R are true, and R is the correct explanation of A .

The correct answer is Option (1) - Both A and R are true, and R is the correct explanation of A.

Explanation:

• Assertion (A): Origin of replication (Ori) is an essential part of a vector. (True)
• Reason (R): Ori is responsible for initiating replication. (True and explains A)

In molecular biology, a vector is a DNA molecule used as a vehicle to carry foreign genetic material into another cell. The origin of replication (Ori) within a vector is indeed an essential component. Ori is a specific DNA sequence where DNA replication begins. It is crucial because it serves as the starting point for DNA replication, enabling the vector DNA to be replicated within the host cell. Ori is a sequence from where replication starts and any piece of DNA when linked to this sequence can be made to replicate within the host cells. This sequence is also responsible for controlling the copy number of the linked DNA. So, if one wants to recover many copies of the target DNA it should be cloned in a vector whose origin support high copy number.