Recombinant DNA in the Lab

Genentech Lab Objects

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. 

A diagram of the recombinant DNA process

Stanley Cohen Lab

Stanley Cohen’s laboratory installed in NMAH’s exhibit Science in American Life, which ran from 1994-2012. Credit:Flickr user Ryan Somma

A year later, they would use this technique to insert a gene from a frog into bacteria, proving that it was possible to transfer genes between two very different organisms. The technology for creating these “molecular chimeras” was patented on December 2, 1980 (US Patent 4,237,224.)  Below are a number of objects used in the Cohen lab during the recombinant DNA experiments.

 

Showing 1 to 6 of 6 items — page 1 of 1

Zeiss Opton Refractometer

Refractometers measure how light changes velocity as it passes through a substance. This change is known as the refractive index and it is dependent on the composition of the substance being measured.
Description (Brief)
Refractometers measure how light changes velocity as it passes through a substance. This change is known as the refractive index and it is dependent on the composition of the substance being measured. In the Cohen lab, this refractometer was one of several techniques used to provide evidence that he and his research team had created a recombinant DNA molecule containing DNA from both a bacterium and a frog.
To conduct the analysis, Cohen separated out the molecule he assumed to be recombinant DNA and measured its refractive index. The index for the molecule fell between the known values for frog DNA and bacterial DNA, suggesting that the unknown DNA molecule was a mixture of the two.
For more information on the Cohen/Boyer experiments with recombinant DNA see object 1987.0757.01
Sources:
“Section 9.4.2: Buoyant Density Centrifugation.” Smith, H., ed. The Molecular Biology of Plant Cells. Berkeley: University of California Press, 1977. http://ark.cdlib.org/ark:/13030/ft796nb4n2/
“Louisiana State University Macromolecular Studies Group How-To Guide: ABBE Zeiss Refractometer.” Pitot, Cécile. Accessed December 2012. http://macro.lsu.edu/howto/Abbe_refractometer.pdf
“Construction of Biologically Functional Bacterial Plasmids In Vitro.” Cohen, Stanley N., Annie C.Y. Chang, Herbert W. Boyer, Robert B. Helling. Proceedings of the National Academy of the Sciences. Vol. 70, No. 11. pp.3240–3244. November 1973.
“Replication and Transcription of Eukaryotic DNA in Escherichia coli.” Morrow, John F., Stanley N. Cohen, Annie C.Y. Chang, Herbert W. Boyer, Howard M. Goodman, Robert B. Helling. Proceedings of the National Academy of the Sciences. Vol. 71, No. 5. pp.1743–1747. May 1974.
Accession File
Description
Refractometer with a “ZEISS / OPTON / Nr 128464 / Germany” inscription used in Stanley Cohen’s laboratory at Stanford University, for research on recombinant DNA. After World War II, the Zeiss firm was split into two parts: VEB Zeiss Jena in the east, and the Opton Optische Werke Oberkochen in the west.
Location
Currently not on view
date made
1946-1953
user
Cohen, Stanley N.
maker
Zeiss
ID Number
1987.0757.28
catalog number
1987.0757.28
accession number
1987.0757
serial number
128646

Light Box

This UV light box was used in the lab of Stanley Cohen at Stanford University in his research on recombinant DNA. UV light boxes are used to help visualize results from of DNA and RNA analysis through gel electrophoresis.
Description (Brief)
This UV light box was used in the lab of Stanley Cohen at Stanford University in his research on recombinant DNA. UV light boxes are used to help visualize results from of DNA and RNA analysis through gel electrophoresis. Molecules subjected to gel electrophoresis create a pattern of bands on a gel medium as they move. Scientists can interpret the pattern to obtain the results of the analysis. However, because the bands of molecules are naturally colorless, they must be dyed to be made visible. Dyes that fluoresce under UV radiation are commonly used. This UV light box was used to provide illumination behind the dyed bands, causing them to fluoresce so that they could be photographed and interpreted.
For more information on the Cohen/Boyer experiments with recombinant DNA see object 1987.0757.01
Source:
Accession File
Location
Currently not on view
user
Cohen, Stanley N.
ID Number
1987.0757.39
catalog number
1987.0757.39
accession number
1987.0757

Electron Microscope Grids and Case

This case held electron microscope (EM) grids used in the lab of Stanley Cohen at Stanford University. Made from tiny circles of copper mesh, EM grids are analogous to the glass slides used to mount samples for viewing under a light microscope.
Description (Brief)
This case held electron microscope (EM) grids used in the lab of Stanley Cohen at Stanford University. Made from tiny circles of copper mesh, EM grids are analogous to the glass slides used to mount samples for viewing under a light microscope. These grids were used to support recombinant bacteria and recombinant plasmids for study and analysis under the electron microscope. One of the grids contains a sample of Cohen and Boyer’s first recombinant plasmid. Photographic images of the first recombinant plasmids used in publications on Cohen and Boyer’s research were made from these grids.
For more information on the Cohen/Boyer experiments with recombinant DNA, see object 1987.0757.01
Sources:
Accession File
“EM Grid Preparation.” Purdue University. Accessed December 2012. http://bilbo.bio.purdue.edu/~baker/documentation/sample_and_prep/b2.htm
Location
Currently not on view
user
Cohen, Stanley N.
ID Number
1987.0757.07.02
catalog number
1987.0757.07.02
accession number
1987.0757

Recombinant DNA Notebook

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, developed techniques that formed the basis of recombinant DNA technology and helped spur the birth of the b
Description (Brief)
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, developed techniques that formed the basis of recombinant DNA technology and helped spur the birth of the biotechnology industry.
This notebook was used by Stanley Cohen in his lab at Stanford University from January of 1972 through 1978 in his study of plasmids—a specific form of DNA found in some organisms, especially of bacteria. It chronicles his research on creating recombinant plasmids, starting with his efforts to break plasmids through mechanical shearing and following through his ground-breaking experiments employing restriction enzymes with Herbert Boyer.
While not technically a lab notebook—one containing a log of daily experiments—the notebook contains extra information on experiments, many sketches and maps of recombinant plasmids, and outlines for papers to be published (including on p. 51 the “Outline for Recombination Paper” that would become the paper “Construction of Biologically Functional Bacterial Plasmids In Vitro” published in the Proceedings of the National Academy of the Sciences in 1973.)
Scientists knew since 1959 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 worked like scissors to cut open the loops of plasmids. Boyer had expertise with restriction endonucleases, and Cohen studied plasmids. After meeting at a conference in 1972, the two decided to combine their research efforts. Following preliminary experiments in 1973, the Cohen-Boyer team was able to cut open a plasmid loop, insert a gene from different bacteria 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 bacteria could use the new genes. They had created the first genetically modified organisms. A year later, the team used this technique to insert a gene from a frog into bacteria, proving that it was possible to transfer genes between two very different organisms. The technology for creating these “molecular chimeras” was patented on December 2, 1980 (U.S. Patent 4,237,224.)
The concept that genes from one organism could be inserted into another and still work was the foundation for the biotechnology industry, which emerged a few years later. Biotech companies use recombinant DNA to insert genes coding for useful products into bacteria and other organisms, turning them into tiny factories for making things from medicine to industrial chemicals. The earliest application of this technology was in the pharmaceutical industry. Learn more about this by searching for “Recombinant Pharmaceuticals” in our collection.
Source: Accession File
Location
Currently not on view
date made
1972-1978
used date
1972-1974
referenced
Boyer, Herbert
user
Cohen, Stanley N.
maker
Cohen, Stanley
ID Number
1987.0757.01
catalog number
1987.0757.01
accession number
1987.0757
patent number
4,237,224

Duostat power supply

This power supply was used in the Stanley Cohen lab at Stanford University to run an electrical current through a vertical chamber for gel electrophoresis (see object 1987.0757.14).
Description (Brief)
This power supply was used in the Stanley Cohen lab at Stanford University to run an electrical current through a vertical chamber for gel electrophoresis (see object 1987.0757.14). Gel electrophoresis was one of the most important tools Cohen and Boyer used to analyze the effects of restriction enzymes on plasmids. The technique allows a way to visualize molecules by separating them out according to their length using an electrical current.
For more information on the Cohen/Boyer experiments with recombinant DNA see object 1987.0757.01
Sources:
Accession File
Location
Currently not on view
user
Cohen, Stanley N.
maker
Beckman Instruments
ID Number
1987.0757.27
catalog number
1987.0757.27
accession number
1987.0757
serial number
8933

Vertical Chamber for Gel Electrophoresis

This vertical chamber for gel electrophoresis was made in 1974 for the Stanley Cohen lab at Stanford University. Gel electrophoresis was one of the most important tools Cohen and Boyer used to analyze the effects of restriction enzymes on plasmids.
Description (Brief)
This vertical chamber for gel electrophoresis was made in 1974 for the Stanley Cohen lab at Stanford University. Gel electrophoresis was one of the most important tools Cohen and Boyer used to analyze the effects of restriction enzymes on plasmids. The technique allows a way to visualize and isolate molecules by separating them out according to their length using an electrical current (for power supply see object 1987.0757.27).
For more information on the Cohen/Boyer experiments with recombinant DNA see object 1987.0757.01
Sources:
Accession file
Location
Currently not on view
user
Cohen, Stanley N.
ID Number
1987.0757.14
catalog number
1987.0757.14
accession number
1987.0757

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