What is recombinant DNA?

• A. Contains genes from the same species
• B. Contains genes from two species
• C. DNA from two different domains
• D. RNA sequences combined

Answer: (B)

Recombinant DNA is a molecule that contains genetic material from more than one source, usually from different species, joined together into a single DNA strand that can be replicated in a host cell. This is achieved by cutting DNA from the donor and the vector with enzymes, inserting the gene of interest into a plasmid or other vector, and sealing the pieces so the combined DNA can be introduced into an organism for expression or study. That cross-species combination is the hallmark of recombinant DNA, which is why describing it as containing genes from two species best captures the concept. The other options miss this key point: staying within one species isn’t recombination, DNA from two different domains isn’t the defining feature (the main idea is mixing genetic material from different origins), and RNA sequences refer to RNA, not DNA, unless an extra step converts RNA to DNA, which is a separate process.