Question

For replication of prokaryotic vector in a host cell, the vector needs

• A. foreign DNA
• B. cloning site
• C. selectable marker
• D. ori

Answer 1

The correct option is D ori

ori is an abbreviation for the origin of replication. It is a sequence of DNA in the vector from where replication starts. It helps in replication of vectors independent of the genomic DNA when inserted into host cells. Therefore, ori is essential for replication of the vector in a host cell.

In recombinant DNA technology, vectors carry the gene of interest into the host cells.

The vectors used in recombinant DNA technology should have cloning sites and selectable marker regions.

Cloning site is the recognition site in vector at which the restriction enzyme binds and makes a cut. Foreign DNA (gene of interest) can be inserted within the restriction site.

The genes encoding antibiotic resistance in the vector are used as selectable markers. They help in eliminating non-transformants and selectively permitting the growth of the transformants.

However, cloning sites, selectable markers and foreign DNA are not needed for the replication of vectors in a host cell.