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Slide 5 
PLASMID 
The London Sunday Times had an elegant diagram, which is in the next 
slide (6), just to illustrate for a moment and to summarize this type of 
procedure. Here is a cell with its chromosome. This is the bacterium. 
We can obtain the plasmid, fragment it, and put it in the test tube. We 
can take the chromosomes of any animal, plant, or other bacterial cell, 
isolate its DNA and fragment it with the same enzyme and add it to the same 
test tube. They will re-associate spontaneously to produce a myriad of 
hybrid structures. One need only introduce these into a new bacterium in 
order to have them multiplied and purified, or what we refer to as being 
cloned. 
One can then grow these bacteria literally in hundreds of gallon quan- 
tities to obtain very large amounts of this highly purified segment of the 
DNA of the original chromosome. 
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