Question

A scientist synthesised a new plasmid for her research work. Her intention was to insert a human gene into the plasmid and harvest large amounts of protein. But in spite of several rounds of experimentation, she found that these bacteria did not produce the protein of choice. What could be the problem with the plasmid?

• A. Transgene is not inserted in the correct position in plasmid
• B. The plasmid does not have the transgene
• C. The plasmid does not have a marker
• D. The ori site is missing

Answer 1

Answer: (A), (D)

The correct options are
A Transgene is not inserted in the correct position in plasmid
D The ori site is missing

Every plasmid should be self replicating. For this, the plasmid should have an Origin of replication or Ori site. Ori, along with the control elements that follow it, forms the replicon and is responsible for the replication of plasmid inside the cell. If the plasmid does not contain an ori site it will fail to replicate. Also if the gene of interest is not inserted at the correct or required position it might fail to express itself.