Question

If a plasmid is having two antibiotic resistant genes, say ampicillin resistant and chloramphenicol resistant. If the plasmid grows in ampicillin containing medium but not in chloramphenicol, what can be concluded?

(a) The insert is not present in any of the gene

(b) The insert is present in ampicillin gene but not in chloramphenicol gene

(c) The insert is present in choramphenicol gene but not in ampicillin gene

(d) The insert is present between both of the genes

The question was asked in an international level competition.

My query is from Vectors topic in portion Simple Cloning of Genetic Engineering

Answer 1

Right choice is (c) The insert is present in choramphenicol gene but not in ampicillin gene

To explain I would say: The insert is present in the chloramphenicol gene and not in the ampicillin gene. As the insert is present in it, it disrupts its function and hence they are not able to grow in chloramphenicol containing a medium.