NOTICES 
33121 
and NIH. This section of the PRG- 
NIH has been rewritten on the basis of 
the Workshop report (see Appendix G 
of the present document). 
Fungal or Similar Lower Eukaryotic 
Host-Vector Systems. Both the 1976 
Guidelines and the PRG-RAC used 
the same short paragraph for this sec- 
tion. giving little detail, because they 
noted "the development of these host- 
vectors is presently in the speculative 
stage.” Since that time a specific host- 
vector system of this class has been 
developed— namely. Saccharomyces 
cerevisiae (baker's yeast)— and other 
similar systems may soon be proposed. 
Accordingly, this section of the PRG- 
NIH has been expanded to give more 
specific instructions on appropriate 
containment levels. 
Synthetic DNA 
Because synthetic DNA is now ex- 
plicitly included in the PRG-NIH (as 
discussed in Part I of this document), 
it was necessary to add language to 
Part in of the PRG-NIH detailing the 
appropriate containment levels for 
these experiments. The RAC at its 
meeting on April 27-28, 1978, approved 
such language, and it has been insert- 
ed in the PRG-NIH. 
Proposed Action: Environmental 
Impact Assessment 
Discussed in the Director’s “Deci- 
sion” accompanying the original 
Guidelines and in the Environmental 
Impact Statement on their release 
are— 
•Tthe containment safeguards, 
physical and biological, that protect 
the laboratory worker, the general 
public, and the environment; 
•The criteria for assessing the possi- 
ble dangers from experiments involv- 
ing recombinant DNA molecules; and 
•The criteria for matching the as- 
sessed possible dangers of individual 
experiments with the appropriate 
safeguards. 
It was these criteria for the selection 
of safeguards that guided the delibera- 
tions of the Recombinant Advisory 
Committee in proposing physical and 
biological containment levels for cer- 
tain classes of experiments. These cri- 
teria were also the basis for recom- 
mendations by the scientific work, 
groups on plants and viruses upon 
which the RAC made further recom- 
mendations In April 1978. The basic 
structure of classification for permissi- 
ble experiments Is maintained 
throughout the PRG-NIH. 
That structure is based on the host- 
vector system and the source of the 
DNA. The E. coli K-12 host-vector 
system is considered first, then other 
prokaryotic host-vector systems, then 
eukaryotic host-vector systems. To 
assist the reader in comprehending 
the structure of the guidelines for per- 
missible experiements, a table is pro- 
vided outlining the containment levels 
given in the current guidelines, the 
PRG-RAC, and the PRG-NIH (see 
App. A). To assist further in the con- 
sideration of experiments under the 
guidelines, NIH reviewed all experi- 
ments supported by NIH as of Decem- 
ber 15, 1977, and characterized them 
in a comparable table (see App. B). 
This shows the containment levels re- 
quired for these experiments under 
the current guidelines, the PRG-RAC, 
and the PRG-NIH. 
The major areas where changes have 
occurred in the PRG-NIH include the 
five categories of exempt experiments 
and those other classes of experiments 
for which containment levels are low- 
ered. Many of the experiments under 
the current guidelines would be 
exempt under the "Exemptions” sec- 
tion of the PRG-NIH, including those 
in which recombinant DNA molecules 
are not in organisms or viruses, are 
from a single nonchromosomal or viral 
source, or are from species that ex- 
change DNA by known physiological 
processes. These exemptions are pro- 
posed because evidence has led to the 
conclusion that the experiments pose 
no significant risk to health or the en- 
vironment. 
Permissible experiments involving E. 
coli K-12 as a host- vector system in 
the PRG-NIH may generally be done 
at lower levels of physical and biologi- 
cal cont ainm ent. A basis for this is the 
abundant scientific evidence that E. 
coli K-12 cannot be transformed into 
a pathogen. (See Pt. EH of this docu- 
ment for a summary of the scientific 
information on the safety of this host- 
vector system.) 
Another reason for reducing con- 
tainment levels when eukaryotic DNA 
is inserted “shotgun” into E. coli K-12 
is new knowledge obtained only re- 
cently concerning the significant dif- 
ference between prokaryotes and eu- 
karyotes in the way proteins are syn- 
thesized. This newly discovered phe- 
nomenon of "intervening,” or 
"spacer,” sequences in eukaryotic 
DNA (1) is discussed in footnote 13 to 
the “Introduction and Overview” of 
the accompanying decision document. 
It makes the expression of eukaryotic 
DNA inserted “shotgun” into E. coli 
K-12 using "nonengineered” plasmids 
less likely than had been postulated 2 
years ago before the phenomenon of 
“intervening” sequences in eukaryotes 
was discovered. 
In the PRG-NIH, containment levels 
have been significantly reduced for 
the use of viruses as vectors and as a 
source of DNA for insertion into E. 
coli K-12. The basis for this was the 
strong support at the public hearing in 
December 1977 for a scientific analysis 
on the use of viruses in these experi- 
ments. As a result, a meeting spon- 
sored by NIH and the European Mo- 
lecular Biology Organization, held in 
Ascot, England, January 1978, pro- 
vided a rationale for reconsidering 
containment levels for recombinant 
DNA experiments involving viral DNA. 
On the basis of the NIH/EMBO report 
and a workshop supported by the NIH, 
the RAC at its April 1978 meeting rec- 
ommended a complete revision of the 
sections of the guidelines dealing with 
viral DNA that is largely reflected in 
the PRG-NIH. The bases for these re- 
visions are explained in detail in the 
reports of the Ascot conference and 
the NTH working group which appear 
in Appendices E and F. The Ascot con- 
clusions relating to the insignificance 
of the hazard associated with viral 
DNA inserts in E. coli K-12 are quoted 
on page 108. 
Few recombinant DNA experiments 
have been conducted with viral DNA, 
since the overly stringent containment 
levels of the current guidelines greatly 
inhibited their use. Under the PRG- 
NIH, such work would be carefully 
monitored to insure that any new in- 
formation on safety or risk were quick- 
ly reviewed and any appropriate 
amendments to the guidelines were 
made. 
Another major area where contain- 
ment levels have been reduced in- 
volves experiments with plant DNA. 
At the December public hearing of the 
Advisory Committee to the Director, 
NIH, scientists from the agricultural 
community strongly recommended 
that the guidelines pertaining to ex- 
periments with plants be reviewed. In 
February, NIH, USDA, and NSF con- 
vened a meeting of plant scientists, 
who made a number of recommenda- 
tions to the RAC. The RAC’s recom- 
mendations from its April 1978 meet- 
ing are reflected in the PRG-NIH. 
Few NIH experiments are in this area, 
and developments win need to be 
closely monitored by the NSF and 
USDA to determine what work is 
being done. Again the recommenda- 
tions comport with safety require- 
ments to assure no significant risk to 
health or the environment. 
In effect, all of the recommenda- 
tions for permissible experiments and 
for those exempt from the guidelines 
are based on new scientific findings or 
on reassessment of previous informa- 
tion. Evidence indicates that work 
should proceed because many recom- 
binant DNA molecules produced in 
laboratories mimic those already pres- 
ent in nature. The PRG-NIH focus on 
areas of experimentation that need 
special attention for the possibility of 
potential hazard. Work in progress 
that is expected to yield valuable new 
information will need to be moni- 
tored— for example, experiments in 
which "engineered” systems should 
permit intentional expression of ge- 
FEDERAi REGISTER, VOL 43, NO. 146— FRIDAY, JULY it. 1978 
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