The following diagram shows restriction sites in E. coli cloning vector pBR322. Find the role of 'X' and 'Y' genes : [figure]
- The gene 'X' is responsible for resistance to antibiotics and 'Y' for protein involved in the replication of Plasmid.
- The gene 'X' is responsible for controlling the copy number of the linked DNA and 'Y' for protein involved in the replication of Plasmid.
- The gene 'X' is for protein involved in replication of Plasmid and 'Y' for resistance to antibiotics.
- Gene 'X' is responsible for recognition sites and 'Y' is responsible for antibiotic resistance.
Answer
(2) The gene 'X' is responsible for controlling the copy number of the linked DNA and 'Y' for protein involved in the replication of Plasmid.
Solution
In the vector pBR322 the two genes shown inside the ring between the Pvu I/ Pst I region and Pvu II are ori and rop; the other two genes are ampR and tetR (antibiotic resistance).
X = ori: the origin of replication, where replication starts; it is also responsible for controlling the copy number of the linked DNA.
Y = rop: codes for the proteins involved in the replication of the plasmid.
Answer: (2)