110 
As of this writing, certain EK2 host-vector systems have 
been recommended for approval and others have been recommended 
and certified (Appendix H, part III). Information on these EK2 host-vector 
systems is available from the NIH Office of Recombinant DNA Activities. 
Appendix H, part I, contains criteria for construction of EK2 systems 
using lambda phage vectors, as recommended by the Working Group 
on Safer Hosts and Vectors : Lambda Phage Systems and adopted by 
IHe Recombinant Advisory Committee at their meeting on January 15, 
1977. 
Appendix H, part II, contains instructions to investigators con- 
cerning data to be submitted on host-plasmid systems proposed for 
EK2 certification, as adopted by the Recombinant Advisory Committee 
on March 21, 1977. 
