Part 2: Boyer and Cohen
About the Program
James Watson and Francis
Crick's discovery of the structure of DNA began a revolution in biology,
chemistry, and genetics that continues today. Between 1953 and 1970, scientists
learned that DNA controls the activides of each cell by specifying the synthesis
of enzymes and other proteins. Armed with this information, as well as an
understanding of how protein synthesis was carried out, two scientists,
Herbert Boyer and Stanley
Cohen, came together and laid the groundwork for recombinant DNA technology,
a way of recombining genes from different sources.
In this program, Boyer and Cohen share their stories on what evolved
into the beginnings of the multi-billion dollar biotechnology industry.
In the early 1970s, Boyer was working at the University of California San
Francisco. His research focused on how particular sequences of nucleotides
could be cut from a strand of DNA using chemicals called restriction enzymes.
He suspected that the cut ends of the DNA sections were "sticky,"
and that a cut end from one piece of DNA would join with a cut end from
another piece of DNA to form a new molecule. But although Boyer recognized
how to create a new DNA molecule, he did not know how such a molecule would
behave. Boyer needed a way to introduce the recombined molecules into living
cells and then to propagate the molecules.
Meanwhile, Cohen was working just 40 miles away, at Stanford University,
on a completely different problem. Cohen studied plasmids-small circular
units of DNA that could carry genetic material from one bacterium to another.
When a plasmid was taken up by a bacterial cell, the plasmid would reproduce
itself, passing along its genetic information to the new host. Thus, it
was possible to change the genetic makeup of bacteria. Cohen and his assistants
developed a method for introducing plasmids into bacterial cells, but they
did not have a way to splice new genetic information into the plasmids.
The union of these two technologies occurred in April of 1972, when Boyer
and Cohen both attended a scientific meeting in Hawaii. Over hot pastrami
and cornedbeef sandwiches, the two scientists planned out a collaboration.
Boyer would take Cohen's plasmids and modify them to form new genetic combinations,
then Cohen would take the modified plasmids and introduce them into bacterial
cells, where the altered genetic material would be reproduced.
The scientific community quickly recognized potential benefits of Boyer
and Cohen's experiments with genetic recombination, as well as possible
dangerous consequences. In the mid-1970s, guidelines were established that
required recombinant DNA research be conducted only in sealed labs with
weakened organisms. Since that time, the regulations have been relaxed.
And despite public concerns, amazing advances in biological research, medicine,
and agriculture have resulted from the techniques first explored by Boyer
and Cohen.
Viewing Objectives
- To learn how information from different scientific fields can be used
to support scientific endeavors.
- To understand the separate contributions of Boyer and Cohen to recombinant
DNA technology.
- To recognize how Boyer and Cohen combined their efforts to produce
manipulated genes.
- To describe how restriction enzymes, plasmids, and bacteria can be
used to synthesize a variety of biological substances.
- To describe some of the social and ethical implications of biotechnology.
Discussion Questions
- The making of bread, cheese, vinegar, and wine are processes which
have been used for thousands of years. In a sense, these processes are
all forms of biotechnology because they rely on the use of living organisms
to produce new substances. How do the genetic engineering techniques started
by Boyer and Cohen differ from these traditional techniques?
- How was the collaboration between Boyer and Cohen similar to that between
Watson and Crick? How was it different?
- The Boyer/Cohen experiment is an example of a scientific achievement
that has had profound social and ethical implications. What are some of
these implica tions? Should scientists be free to pursue research regardless
of its impact on society? Why or why not? What are some other types of
scientific research that have had a similar impact on society?
- If you were appointed to a regulatory commission for recombinant DNA
technology, what are some of the regulations you would propose? Why? How
would you suggest the government enforce your regulations? What other questions
would you raise?
Relelted Activities
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Resource Book Index: Stories from the Scientists
