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Timeline 2007
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A Timeline of Biotechnology 540
August 28, 2007

 

Class Questions - Discuss with a partner

 

(I) Nature, January 2003: The Birth of Biotechnology
* Why were Cohen and Boyer at the same meeting in Hawaii in 1972?

* Cohen studied: Plasmids

* Boyer studied: Restrictions Enzymes

* Why do bacteria make restriction enzymes? To restrict entry by phages

* Of what use to bacteria are plasmids? Transfer genes from cell to cell

* What was the idea Cohen and Boyer discussed (in the Deli) to get their two research programs together? Open plasmid with RE, and cut DNA to insert with same RE - mix
"Both saw the potential for combining the two discoveries into what would become genetic engineering. First, use EcoRI to slice both plasmid DNA and the DNA of choice. Then, with the identical DNA termini exposed, attach the DNA fragment to the plasmid DNA, and clone the whole in E. coli."


(II) From Morrow et al (Cohen and Boyers original paper, May 1974)

 

1. What is pSC101? TetR plasmid, named for Stanley Cohen

2. What was the source of the DNA cloned into pSC 101? X. laevis. As frogs go, not the prettiest (sorry Xenopus)

3. Fig 2 - What is the 5.8 kb fragment? Linear pSC101 cut with EcoRI in this case

4. Fig 2 - What are CD42, CD30, CD35, CD4, and CD18? pSC101 plasmids containing inserts - again cut with EcoRI to release the inserts


5. What is a minicell and what does it have to do with this procedure? Cells 1/10 the size of a regular E. coli cell, lack DNA; produced during abnormal cell division of a particular E. coli strain; can be used to study gene expression in the absence of chromosomal background; RNA from these cells was hybridized with X. laevis rDNA Fig 4.

 

6. In retrospect, why do you think they chose to clone rDNA into pSC101 rather than another gene? rDNA does not make a protein - it just makes the components of ribosomes = and all cells have virtually identical ribosomes...seemed like a safe choice.



7. Read the last sentence of this paper, and say "like wow..."

 

 

(III) Potential Biohazards of rDNA molecules July 1974

 

1. Who authored this article? Paul Berg, Cohen and Boyer, David Baltimore etc

 

2. Why was the use of E. coli of particular concern these scientists?

 

“E. coli commonly reside in the human intestinal tract, and they are capable of exchanging genetic information with other types of bacteria, some of which are pathogenic to man. Thus, new DNA elements introduced into E. coli might possibly become widely disseminated among human, bacterial, plant, or animal populations with unpredictable effects.”

 

 

3. What were the 4 recommendations of the authors?

First, voluntary moratorium on:

  • Type I: plasmids w/ antibiotic resistance or bacterial toxins
  • Type II: DNA from oncogenic viruses or other viruses

Second: - 'Carefully weigh' rDNA expts with animal DNA - many types of animal cell DNAs contain sequences common to RNA tumor viruses…. biological properties cannot be predicted with certainty

Third, NIH Director is requested to

Fourth, an international meeting of involved scientists from all over the world should be convened early in the coming year to review scientific progress in this area and to further discuss appropriate ways to deal with the potential biohazards of recombinant DNA molecules.

 

Last sentence?

 

Nonetheless, our concern for the possible unfortunate consequences of indiscriminate application of these techniques motivates us to urge all scientists working in this area to join us in agreeing not to initiate experiments of TYPES I and II above until attempts have been made to evaluate the hazards and some resolution of the outstanding questions has been achieved

(IV) Summary Staetment from Asilomar: Paul Berg, Maxine Singer June 1975

1. What were the 2 major concerns of Asilomar participants (second paragraph)

2. What two types of 'biological barriers' do the authors recommend for containment (top of pg 1982)?

3. Please be sure to glance over (NOT commit to memory) the

 

 

Objectives specific to this lecture

1.Identify Nobel-winning scientists and their research stated above. Why? because every self-respecting Biology major SHOULD!
2.Explain how the Cohen-Boyer partnership resulted in 'the birth of biotech' (aka Cloned beef to cloning), the role of Robert Swanson developing the biotechnology company Genentech

3.Explain the major results of the Cohen-Boyer 1974 PNAS paper. We will go over this paper in class Tuesday evening
4. What were the major recommendations of the 1974 paper "Potential Biohadards of Recombinant DNA molecules? What was the outcome of this manuscript?

5. What were the major conclusions from Asilomar conference and what are their significance in the use of recombinant DNA technology? Be able to discuss the the initial concerns and recommendations that surround this important event.

 

However, in later discussions, we will focus in on more specific objectives for all the rest of the topics: the Human Genome Project, Cloning Animals, Ag-Biotech, Stem Cells and Stem Cell legislation, Cloning Human Cells, etc.

 

You will want to keep returning to this timeline to help you study for those particular lectures. Do you have to know dates and the 'order' of particular events? NO, but I will give you essay exam questions that will ask you to recall and discuss specifics about the events, given the dates and historical context. More on this later!

(back to top); (back to Biol 540 schedule)

 

Copyright Kathleen A. Marrs 1998-2007