This document summarizes the key steps in recombinant DNA technology. It describes the required features of plasmids used for cloning, including an origin of replication, selectable marker, screenable marker, and cloning sites. It explains how restriction enzymes are used to cut DNA and how ligases join DNA fragments. It describes transforming bacteria with recombinant plasmids and selecting for transformed colonies. Finally, it provides examples of commercially available proteins and therapeutics produced through recombinant DNA technology, including hormones, enzymes, antibodies, and fusion proteins.