Plasmid pBR322 has PstI restriction enzyme site within gene amp R that confers ampicillin resistance. If this enzyme is used for inserting a gene for ß-galactoside production and the recombinant plasmid is inserted in an E.coli strain (1) It will be able to produce a novel protein with dual ability. (2) It will not be able to confer ampicillin resistance to the host cell. (3) The transformed cells will have the ability to resist ampicillin as well as produce ß-galactoside. (4) It will lead to lysis of host cell.