What is insert DNA?

Correct answer: A desired DNA fragment added into a vector

Insert DNA is the foreign or desired DNA fragment selected for cloning and joined to a vector. The vector acts as a carrier, while the insert contains the sequence that researchers want to maintain, amplify, express, or study. In a recombinant-DNA experiment, the vector and insert are commonly cut with compatible restriction enzymes and then joined by DNA ligase. The resulting recombinant vector can be introduced into a host cell for replication. Option A is correct because it gives the operational definition of an insert. A fat layer, a host wall, and gel colour are not DNA molecules and do not represent the cloned target sequence.