a gene for such a protein is another reason for insisting on 
stringent containment of shotgun experiment in bacterial hosts 
or using uncrippled eukaryotic viral vectors when expression 
of genetic information is possible. 
Dr. Martin's conclusion that the absence of mRNA maturation 
enzymes all but eliminates the risk of cloning eukaryotic DNA 
in bacteria can and should be tested. Several questions need 
to be answered : 
(1) It is possible that not all eukaryotic genes — 
particularly those for smaller proteins, peptides, and active 
RNAs — contain introns (unexpressed DNA sequences in a 
eukaryotic gene) . Genes without introns may not require 
processing for functional expression. 
(2) Fragments of some proteins have been found to retain 
biological activity. Examples range from cytochrome bs to the 
proteins coded for by the rll region of the T-even phages.— ^ 
(3) If DNA sequences containing introns are expressed in 
bacteria in the absence of RNA processing, the (nonfunctional) 
proteins synthesized may have immunological cross-reactivity 
with their native relatives or with similar proteins in other 
species. The resulting bacteria may then be vectors for new 
autoimmune diseases . 
The problem of autoimmune disease and recombinant DNA was 
discussed at the Falmouth conference by Dr. King. (F: 663-667) . 
19 / Stent, 0 £. cit . and B. Hagihara et al . , The Enzymes , 
P. D. Boyar, ed. (New York: Academic Press, 1975), 
pp. 550-594. 
[A-198] 
