What does 'scarless' mean in Golden Gate assembly?

• A. Fragments are ligated with scars
• B. No extra sequences remain between assembled fragments
• C. It uses no enzymes
• D. It requires homologous sequences

Answer: (B)

Scarless means that when you join several fragments, the final DNA has no extra, non-native sequence at the junctions between pieces. In Golden Gate assembly, Type IIS restriction enzymes cut outside their recognition sites, so those sites are removed during the assembly. The fragments are joined by designed overhangs, producing seamless junctions where no residual restriction-site scars remain. So there are no leftover sequences introduced by the assembly process at the joins. This is why the correct interpretation is that no extra sequences remain between assembled fragments. The method does use enzymes, and it doesn't rely on homologous sequences, which is why the other statements aren’t correct.