Slide 10 
Guidelines for Experiments with E. coli "Host-Vector" 
Systems II. 
'Foreign' DNA = Mixed Fragments = "Shotgun" 
Containment 
Foreign DNA Source 
Physical 
Biological 
Prokarydtes: 
"Exchangers" 
Class 1 (CDC) 
PI 
EK1 
Class 2 (CDC) 
P2 
EK1 - EK2 
Plant pathogens 
P2 
EK1 - EK2 
"Non-exchangers" 
Class 1 (CDC) 
P2 
EK1 
Class 2 (CDC) 
P3 
EK2 
Plant pathogen 
P3 
EK2 
If 'drug' problem 
P2* 
EK2* 
*Or higher, depending on virulence. 
Slide 11 
Guidelines for Experiments with E. coli "Host- Vector" 
Systems IV. 
“Foreign DNA" = Purified fragment of chromosomal DNA 
a) greater than 99% pure 
b) absence of harmful genes 
Then: 
Decrease Physical Containment one step 
(P3 -> P2) 
or 
Decrease Biological Containment one step 
(EK2 -> EK1) 
from containment required for "shotgun" 
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