A general method for the cloning of DNA fragments in tandem arrays is presented. Synthetic directional adapters are attached to the fragment ends to establish complete control over fragment orientation during ligation. Use of these directional adapters thereby ensures the production of direct repeats, an arrangement essential for clone stability. The technique involves a protocol that is both less complex and less time-consuming than previous methods. Using this technique, a 10-min ligation has yielded a plasmid containing 20 copies of a 151-bp fragment.
Cloning, Molecular DNA