Biotechnology at 25: Perspectives on History, Science, and Society

Saturday, March 13, 1999

Stanley Cohen, M.D.
Co-developer of recombinant DNA technology and Professor of Genetics, Stanford University.


Use this index to jump into Dr. Cohen's talk at any point. You can also click on some of the scientific terms and go to the glossary.
Introduction of rDNA and the concepts of genetic engineering.
Investigation of plasmids and antibiotic resistance.
Cohen needed to develop methods for cloning in bacteria.
Began working with E. coli bacteria to transform cell plasmids.
Antibiotic resistance genes were used to take plasmids apart and "recombine" (rDNA) them.
Gobind Khorana's "paired" nucleotides in single strings of DNA was the key. The DNA enzyme ligase sealed the molecules together. Vittorio Sgaramella discovered that blunt DNA ends that lacked complementarity, were joined by DNA ligase found in the T4 bacterial virus
Vittorio Sgaramella discovered that blunt DNA ends that lacked complementarity, were joined by DNA ligase found in the T4 bacterial virus
The terminal transferase enzyme was discovered at the Oak Ridge National Laboratory. R.H. Jensen used DNA ligase to clone nicks in rDNA, but was not successful.
Peter Lobban discovered manipulations for permanent fusion of DNA fragments. Paul Berg linked the E. Coli virus, lambda, which sparked a biohazards controversy
"Palindrome" enzymes were discovered by Werner Arber and Hamilton Smith.
Historic meeting in Hawaii, where many scientists discuss the possibility of cloning.
Thoughts on how combining methods might work
May 1973 paper described results of collaboration.
DNA experiments were conducted by Dr. Cohen and Annie Chang at Stanford, and by Herbert Boyer at UCSF. They presented their paper to the National Academy of Sciences, which was the basis for the basic cloning patent.
Eukarotic DNA segments were propagated in E. Coli.
Science isn't done in a vacuum. If Cohen and Boyer hadn't discovered rDNA, someone else would have.

 

 


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