Recombinant DNA in the Lab

In a series of experiments, between 1972 and 1974, Stanley Cohen, Herbert Boyer, and their colleagues, at Stanford University and the University of California, San Francisco built on the work of recombinant DNA pioneers such as Paul Berg to develop techniques that would form the basis of recombinant DNA technology. These experiments helped spur the birth of the biotechnology industry.

Since 1959, scientists knew that bacteria contain extra loops of DNA called “plasmids” in addition to their chromosome. In nature, bacteria can swap these plasmids with one another, quickly transferring beneficial genes like those that code for antibiotic resistance.  By the early 1970s, investigators had isolated several plasmids as well as special enzymes known as “restriction endonucleases” that work like scissors to cut open the loops of plasmids.  

Herbert Boyer had expertise with restriction endonucleases and Stanley Cohen studied plasmids, and after meeting at a conference in 1972, the two decided to combine their research efforts. After preliminary experiments in 1973, the Cohen-Boyer team was able to cut open a plasmid loop from one species of bacteria, insert a gene from different bacterial species and close the plasmid. This created a recombinant DNA molecule-- a plasmid containing recombined DNA from two different sources. Next, they inserted the plasmid into bacteria and demonstrated that the recombinant DNA could be used by bacteria. The team had created the first genetically modified organisms.