Final answer:
DNA ligase is the enzyme that attaches a target gene to a desired location, enabling the stable incorporation of the gene for subsequent expression or replication.
Step-by-step explanation:
The enzyme that attaches the target gene to a desired location is DNA ligase. DNA ligase is responsible for splicing DNA at a specific point, allowing the insertion of a new piece of DNA. This action is distinct from the cleavage of DNA, which is carried out by restriction enzymes, and it is an essential step in molecular cloning and various DNA repair processes. By facilitating the joining of two DNA fragments - such as the target gene and a plasmid vector - DNA ligase ensures stable incorporation of the gene of interest into the desired location for subsequent expression or replication.