Dr. William Gartland 
Page five 
There are a number of aspects of gene transfer experiments 
that would make Rlfkln's proposal untenable In practice. His 
proposal specifies that genetic traits from "one mammalian 
species. . .(should not be Introduced) .. .Into the germllne of another 
unrelated mammalian species." There are a number of problems with 
this definition. First of all, why allow transfer of bacterial. 
Insect and frog traits Into mammals but not traits from other 
mammals? Second, what would be the status of synthetic genes or 
genes that had been mutated so that they no longer resembled the 
species of origin? Also, consider the situation where the genetic 
traits of mice and rats are Identical (by DNA sequence), could the 
rat trait be Introduced Into the mouse? Now suppose that the 
traits differ slightly (one nucleotide change): does that preclude 
gene transfer even though the function of the traits might be 
Identical? Or In Rlfkln's terms, does one nucleotide change 
constitute an affront on the "telos"? If so, then the "telos" of 
organisms Is changing naturally all the time. Perhaps understanding 
why foreign genes are being Introduced Into mammals Is worth 
reiterating. There are two practical reasons. One Is that the 
genetic trait of Interest may not have been Isolated from the 
species Into which the gene will be Introduced. This was the case 
with growth hormone. The mouse growth hormone gene has not been 
Isolated. While we believe that It would be technically feasible to 
Isolate the mouse growth hormone gene and obtain the same results. 
It did not seem worth the time and expense to Isolate It when the 
functionally equivalent rat and human genes were available. The 
second reason Is that It Is easier to recognize the foreign gene 
(and Its RNA and protein products) If It differs from the 
corresponding endogenous gene. The foreign genes are "marked" and 
easy to distinguish from the resident genes by standard techniques. 
However, very subtle differences could be used to "mark" genes so as 
to avoid using genes of another species, but Is It worth the 
effort? 
These are some of the more compelling arguments that we feel 
justify not amending the N1H guidelines for recombinant DNA 
experimentation as proposed by Rlfkln. 
We are. 
Ralph L. Brlnster 
[ 458 ] 
