APPENDIX E 
humans or primates and other relevant environments. 
Ek2 and EK3 host vector systems must be certified as such by the 
Director, NIH, after evaluation and recommendation by the Advisory Committee. 
Detailed data on the relevant properties of the system must be submitted 
for consideration by the Committee. Thus far (January, 1977) the following 
EK2 systems have been certified: col i strain XI 776 with either plasmid 
pSCIOl or plasmid pCRI , a derivative of colEI. One lambda phage derivative 
(6) was certified in April, 1976 and several others, to be used in conjunction 
with specified E. col i K12 host cells, are under consideration by the Committee. 
No EK3 systems have been submitted for certification as yet. Information concernin 
certified systems and their ava il ability can be obtained from the office mentioned 
3/ 
i n footnote 1 
Classification of Experiments Currently permissible with E. col i K12 
host-vector systems . 
Having defined the several levels of physical containment and biological 
containment the specific recommendations for experiments using the E. col i K12 
host-vector systems can be described. Each type of experiment is assigned both 
a physical containment level, that is a P level, and a biological containment 
level, that is an EK level and the particular combination of the two reflects 
the severity of the estimated potential hazard. The Guidelines are organized, 
for the col i systems, according to the source and nature of the foreign 
DNA, as outlined in Fig. 2. A samp I e of DNA conta i n i ng essent i a I I y all 
the genetic information of an organism can be isolated and fragmented. 
If the experiment involves such a mixture of DNA fragments, it is referred 
to as a "shotgun" and will call for a certain level of containment. Exoeriments 
Appendix E — 13 
