The linking of antibiotic resistance gene with the plasmid vector became possible with
The correct option is A DNA ligase A plasmid can be used as vector to deliver any piece of foreign DNA into the host organism. The linking of antibiotic resistance gene with the plasmid vector became possible with the enzyme DNA ligase, which acts on the cut ends of the DNA molecules and joins their ends. The phosphodiester bonds is ligated which results in the attachment of the two nucleotides in the fragments. This makes a new combination of circular autonomously replicating DNA created in vitro and is known as recombinant DNA. When this DNA is transferred into Escherichia coli, a bacterium closely related to Salmonella, it could replicate using the new hosts DNA polymerase enzyme and make multiple copies.