-3- 
RESULT IN THE DISCOVERY OF A MECHANISM FOR INSERTING NEW GENES INTO PLANTS. 
THE CURRENT GUIDELINES ESTABLISHED IN 1976 HAVE UNNECESSARILY RESTRICTED 
THE CLONING OF DNA FROM PLANTS AND FROM PLANT PATHOGENIC FUNGI, BACTERIA, 
AND VIRUSES IN SEVERAL WAYS: i) MOST PERMISSIBLE EXPERIMENTS WITH DNA 
FROM THESE SOURCES REQUIRE P2 OR P3 CONTAINMENT. THIS RESTRICTION APPEARS 
TO HAVE BEEN BASED ON THE UNFAMILIARITY OF NIH WITH PLANTS AND THEIR PARA- 
SITES RATHER THAN ON EVIDENCE OF GREATER RISK INVOLVING THESE ORGANISMS, 
ii) THERE IS A PROHIBITION ON EXPERIMENTS WHICH MIGHT INCREASE THE VIRULENCE 
AND HOST RANGE OF A PLANT PATHOGEN, AND THIS IN EFFECT RULES OUT COMPLEMENTA- 
TION STUDIES WITH AVIRULENT MUTANTS AND iii) THF.RE IS A REQUIREMENT THAT ALL 
HOST VECTOR SYSTEMS BE CERTIFIED BEFORE ONE CAN DO SELF CLONING EXPERIMENTS 
OR REINTRODUCE DNA, WHICH HAS BEEN CLONED INTO E. COLI BACK INTO ITS HOST OF 
ORIGIN. THE LATTER EXPERIMENT IS, OF COURSE, NECESSARY IF GENES FOR PATHO- 
GENICITY OR NODULATION ARE TO BE STUDIED SINCE THESE PROPERTIES WOULD NOT BE 
EXPRESSED IN E. COLI . MOREOVER, THIS REQUIREMENT FOR CERTIFICATION OF HOSTS 
CREATES PROBLEMS EVEN FOR THE GENETICIST NOT INVOLVED IN RECOMBINANT DNA 
RESEARCH. MANY VERY USEFUL PLASMIDS HAVE BEEN CONSTRUCTED IN E. COLI BY 
RESTRUCTURING DRUG RESISTANCE PLASMIDS IN VITRO . AT PRESENT, THESE PLASMIDS 
CANNOT BE TRANSFERRED TO OTHER BACTERIA WITHOUT PRIOR NIH APPROVAL EVEN THOUGH 
THE PARENT PLASMIDS HAVE BEEN INTRODUCED INTO THE SPECIES IN QUESTION WITHOUT 
APPARENT DANGER. 
THESE REQUIREMENTS FOR HIGH CONTAINMENT LEVELS AND CERTIFICATION OF HOST 
VECTOR SYSTEMS HAVE DISCOURAGED THE USE OF CLONING IN WORK WITH PLANTS, 
NITROGEN FIXERS AND PLANT PATHOGENS. AGRICULTURAL SCIENTISTS ARE OFTEN 
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