recombinant DNA but without the recombinant DNA being present in 
the final transgenic animal. Dr. Mulligan cited a scenario of a 
deletion introduced into a mouse in which recombinant DNA as 
defined by the NIH Guidelines would not be present in the final 
construct . 
Dr. Gottesman replied by saying there had been an amendment that 
the RAC had contemplated some time ago which would have exempted 
deletions from the NIH Guidelines. Dr. Gartland said the 
amendment referred to by Dr. Gottesman was also currently 
awaiting environmental assessment but said that deletions, in the 
context of contained research, were exempt. 
Dr. Erickson said the discussion of deletions was not important 
in regard to transgenic animals because of the importance of 
having a DNA marker in such animals for research purposes. 
However, he felt Dr. Johnson's comment was an issue which was of 
importance and he felt the working group meant the wording to 
address sexual transmission of the modified genome outside the 
laboratory. 
Dr. Gellert said there were ways he could think of whereby 
rearrangements into the germ line of an animal would not contain 
recombinant DNA. He noted it is possible to turn on the 
immunoglobulin recombination system with a transient plasmid, 
then have the plasmid remove itself from the germ line, producing 
an animal with rearranged immunoglobulin genes. 
Mr. Mannix asked if the word "foreign" should not be added to 
"DNA" to make it clear that deletions, rearrangements and 
duplicate gene copies were not intended to be covered. Dr. 
Gottesman said she felt the word "foreign" itself would have to 
be defined and would only make the situation more complex. 
Dr. Gellert said current technology in introducing viral genomes 
in transgenic animals was to clone a retroviral genome, cut it 
back out of the plasmid and then introduce it into the germ line 
of animals. He could envision a similar experiment being done by 
cultivating a retrovirus in a suitable cell line, letting the RNA 
become reverse transcribed into double-stranded DNA in the viral 
cores, reisolating the material and using that to generate a 
transgenic animal. Thus, none of these steps would qualify as 
"recombinant DNA," but the same product would result as from the 
recombinant method. 
Dr. Neiman replied the working group was aware of just such an 
experiment and discussed it at some length. He was not sure the 
experiment could be done at present because of the low efficiency 
of introduction of DNA and the numbers of transgenics 
successfully produced would be small in terms of the number of 
injections. The result of such viral infections are populations 
of DNA of unknown content and Dr. Neiman didn’t feel many 
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