SEPTEMBER 6-7 - MINUTES OF MEETING 
5 
VI. PROPOSED REDUCTION IN CONTAINMENT FOR E. COLI K-12 HOST-VECTOR SYSTEMS 
A proposed exemption under Section I-E-5 of the Guidelines for recombinant 
DNA experiments involving EKl and EK2 host- vector systems had been proposed 
by Drs. Rowe and Campbell. The proposed exemption was published for comment 
in the Federal Register on April 13, 1979. 
At its May 21-23, 1979 meeting, the RAC discussed the proposed exemption 
at length. During this discussion a proposal was made that experiments 
involving E. coli K-12 host-vector systems should be permitted under Pi 
conditions with the stipulation that such experiments be registered with 
the local IBC. There was discussion as to whether these procedures should 
also be considered for all classes of exempt experiments. The RAC voted 
that a working group should be appointed to conduct an analysis of E. coli 
K-12 host-vector systems with regard to potential biohazards, to develop 
recommendations, and to report to the full RAC at its September 1979 meeting. 
Dr. Setlow appointed Drs. Williams (chairman), Gottesman, Novick, and 
Proctor to this working group. The Working Group deliberated during the 
summer and recommended the following formulation of the proposed exemption: 
"Those recombinant DNA molecules that are 
propagated in E. coli K-12 hosts not 
containing conjugation-proficient plasmids 
or generalized transducing phages, when 
lambda or lambdoid bacteriophages or 
non-con jugative plasmids are used as vectors, 
can be handled at Pi and are exempted from 
the Guidelines." 
This proposal was published for comment in the Federal Register on July 
31, 1979. Prior to the September 6-7, 1979 meeting, 14 letters commenting 
on the proposal were received. All the commentators in these letters 
expressed strong support for the proposed exemption. Most of the commentators 
supported the original proposal for complete exemption as published in the 
Federal Register of April 13, 1979. One of these letters (710) was signed 
by 183 scientists who attended the 1979 Gordon Research Conferences on 
Nucleic Acids and on Biological Regulatory Mechanisms. 
Prior to the September meeting, the RAC had received a background document 
from the working group and a manuscript on a framework for assessing the 
potential risks of recombinant ENA experiments prepared by Dr. Sidney Brenner 
for the United Kingdom Genetic Manipulation Advisory Group. The RAC also 
received an additional critique of the polyoma risk-assessment experiments 
prepared by Dr. Barbara Rosenberg. 
The RAC discussed the proposal of the working group at length at the meeting. 
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