Question

How is it possible that viral DNA can be inserted into the genome of bacteria?

Answer 1

Sticking the vector and the gene together
Scientists mix the gene and the opened vector together with a bacterial enzyme called DNA ligase. The ligase sticks DNA ends together to form a single circular molecule that includes both the vector and the gene.

Answer 2

A bacterial enzyme called DNA ligase is used to combine the gene with the opening vector. The ligase joins the ends of the DNA strands to produce a single circular molecule that contains the vector as well as the gene.