272 Action oi the Genetic Material 



our ideas on pseudoallelism, which are based upon pattern effects 

 within a chromosomal section without recourse to individual genes. 

 Pontecorvo realizes that his results may also be interpreted in this 

 sense. We may expect, in this case, he writes, "all genes to show, to a 

 greater or lesser degree, the behavior of those mentioned here. This 

 means that there would not be, at the biological level, any further di- 

 visibility of the action of the gene, and that of the mutant alleles of a 

 gene, taken two by two, some may recombine giving the normal 

 allele — i.e., those in which the mutated or damaged elements are not 

 in common — and some may not — i.e., those having in common part or 

 all of the mutated elements." 



My objections to this general idea stem mainly from the fact that 

 the millimicromolar action of genie material or its first products re- 

 maining in situ would be a special feature of some chains of reactions 

 requiring the assembly line because of the scarcity or immovability 

 of the components. Since such reactive partners would at best be 

 relatively rare, we would have an explanation which does not include 

 all primary genie actions but only one class. All the regularities of 

 genetics and cytogenetics make us expect that the primary genie 

 actions are of the same type for all of them. Thus I am not certain 

 that one should conclude from these experiments that reactions in situ 

 between adjacent or nearby genie materials or primary products (in 

 the sense of duplication products) are the typical beginning of genie 

 action. 



The most important genie products should be the specific 

 enzymes, and a great deal of discussion in biochemical genetics 

 touches upon this fact. We shall discuss this later from the point of 

 view of general genie action. Here we are concerned only with primary 

 genie action at the site of the genie material. The first product, either 

 remaining and reacting in situ or immediately pushed off into the 

 nucleus, may be an enzyme or a direct precursor of an enzyme, formed 

 as a duplicate of a part of the genie material, as discussed in the 

 introduction to this chapter. This would imply the possibility of a 

 primary relationship between the genetic material and one of its final 

 products without intervening steps. Monod (1947) and Spiegelman 

 (1948) have developed ideas concerning the formation of enzymes 

 and their specificity. They assume that the same enzyme precursors 

 may be transformed into different specific enzymes in one unique 

 biochemical step. If this were so at the primary level, a single primary 

 genie product in situ might be such a precursor destined to be trans- 

 formed later into many individual enzymes either from accumulated 



