In cloning workflows, why would you choose Gibson assembly over traditional ligation-based cloning?

• A. It allows seamless joining of multiple fragments with overlapping ends in a single isothermal reaction.
• B. It is cheaper than ligation.
• C. It always yields higher copy number plasmids.
• D. It requires no DNA fragments to insert.

Answer: (A)

The essential idea here is that Gibson assembly lets you fuse multiple DNA fragments together seamlessly in one isothermal reaction by using designed overlaps between the fragments. You prepare fragments with short, matching end sequences. A 5' exonuclease creates single-stranded overlaps, the fragments anneal at those overlaps, a polymerase fills in any gaps, and a ligase seals the nicks. Because the overlaps guide the assembly, you can order and join many pieces without introducing extra sequences at the junctions (no scar sites) and without relying on restriction enzymes. This makes the process fast and flexible, especially for assembling complex constructs or plasmids with several inserts, since everything happens in a single tube and you don’t have to hunt for compatible restriction sites.

That’s why this method is preferred over traditional ligation-based cloning: it’s not limited to two fragments or to ends created by enzymes, it can assemble multiple fragments in one shot, and it produces seamless junctions. The other choices aren’t reliable reasons for choosing Gibson assembly—cost can vary and isn’t guaranteed, copy number depends on the plasmid and host rather than the assembly method, and you do need DNA fragments to insert for any cloning to occur.