31 
P 3 + EK1 or P2 + EK2. Mitochondrial or chloroplast DNA from other 
eukaryotes: P2 + EK1 . Otherwise, the conditions given under shot- 
gun experiments apply. 
( i v ) Prokaryotic plasmid and phage DNAs 
Plasmids and phage from hosts that exchange genetic 
information with E. coli - Experiments with DNA recombinants 
formed from plasmids or phage genomes that have not been characterized 
with regard to presence of harmful genes or are known to contribute 
significantly to the pathogenicity of their normal hosts should use 
the containment conditions specified for shotgun experiments with DNAs 
from the respective host. If the DNA recombinants are formed from 
plasmids or phage that are known not to contain harmful genes, or 
7 
from purified and characterized plasmid or phage DNA segments known 
not to contain harmful genes, the experiments can be performed with 
PI physical containment + an EK1 host-vector. 
Plasmids and phage from hosts that do not exchange genetic 
information with E. coli - The rules for shotgun experi- 
ments with DNA from the host apply to their plasmids or phages, with 
the following qualifications. Experiments with DNA recombinants formed 
with foreign plasmids or phage containing genes which extend the range 
of resistance of the recipient to therapeutical ly useful drugs should 
use P3 physical containment + an EK2 host-vector. The minimum containment 
7 
The DNA preparation is defined as purified if the desired DNA represents 
at least 99% (w/w) of the total DNA in the preparation, provided that it 
was achieved or verified by more than one procedure. 
[ 102 ] 
