(A) Splicing overlap extension PCR—indicative diagram. Two separate PCR are done with some overlap between the middle primers. These amplify the two pieces of DNA you wish to splice together. The products of these two separate PCR are then mixed, and along with the outer primers, a further PCR is performed. The two products from the first reactions are complementary and thus anneal linking the two fragments together. (B) Gibson assembly. Two separate PCR are done with some overlap between the middle primers as per with splicing overlap extension PCR. These result in two PCR products, which have a region, which is complementary. An exonuclease enzyme is added which removes single strands from each end producing sticky ends, similar to those produced by restriction enzymes. The exposed ends can then be annealed and ligated. Both splicing overlap extension PCR and Gibson assembly can be scaled to join multiple fragments together.