Final answer:
Donor DNA in recombinant DNA technology is a sample of DNA containing the gene of interest that is inserted into a vector for expression in a host organism.
Step-by-step explanation:
When referred to in the context of recombinant DNA technology, donor DNA is a sample of DNA molecules containing the gene of interest. It is the piece of DNA that is selected and physically extracted from a source organism because it carries the specific sequence or gene that scientists wish to study, manipulate, or use in another organism. This donor DNA is then typically inserted into a vector (like a plasmid or a modified virus) that will carry the gene into the host cell where it can be replicated, transcribed, and translated as desired, leading to the production of recombinant proteins or the expression of the target gene within the new organism.