50 YOS, BADE AND JEHLE 



It might perhaps be permissible to make now a minor observation regarding 

 orientation effects in synapsis. If one considers the London force between two 

 long rods lying parallel, side by side, one runs into the problem that correspond- 

 ing sections of the rods which lie side by side do not at all have the advan- 

 tageous mutual orientation recjuired by the London interaction (in the general 

 case of anisotropic polarizabilities). The proper mutual orientation of identical 

 or homologous genes in synapsing chromosomes can, however, be facilitated 

 by the flexibility, or by coiling of the chromosomes; in this regard, it may be 

 interesting to remark that two identical big low-pitch helical coils, lying along 

 side each other with their axes parallel, permit the directly adjacent parts of 

 the neighbor coils to form identical and properly oriented pairs (if the threads 

 out of which the big-low-pitch helical coils are wound, permit some ±90° 

 torsion). The big coils might be turned together like a two stranded rope. In a 

 similar fashion four identical low-pitch helical coils can be assembled into a 

 twined four-stranded rope with all directly adjacent parts specifically interact- 

 ing. Formation of three (or other than two or four) stranded ropes do not permit 

 all adjacent parts to be identical and properly oriented. 



As to the problem of self-duplication, jMuller wrote, "That this ability to 

 duplicate itself is based in unique properties of some relatively stable genetic 

 material, rather than in the multitude of diverse substances and processes that 

 engage in cycles, may, curiously enough, be inferred more especially from the 

 behavior of the real exceptions to the principle of inner stability. These all 

 important exceptions are the comparatively rare cases in which, even in a 

 "pure line", sudden permanent deviations of type or "mutations", take place. 

 Although of most varied kinds, as judged by their unlike effects on the or- 

 ganism, it is characteristic of the great majority of these changes that in 

 succeeding multiplication they may become regularly incorporated, that is, 

 they now take their place as part of the again stable, self-multiplying pattern. 

 It is scarcely conceivable that, if the reproduction of every part of the organism 

 were due primarily to the marvelous concatenation of a host of individual proc- 

 esses of the cycle, these could have been so arranged that, when disturbed in 

 any one of the innumerable ways, they would still be able to work effectively 

 in reproduction, yet in a manner so correspondingly adjusted as now to effect a 

 repetition of just the given alteration. Rather must it be inferred that the 

 essential process of reproduction consists in the autosynthesis of a controlling 

 genetic material, and that this occurs through some sort of laying down of the 

 raw material after the model of the genetic material already present, no matter 

 what — within certain very wide limits — the pattern of that genetic material 

 happens to begin with. ..." 



"In this as in previous proposals for explaining gene duplication, the "raw" 

 materials in the medium are supposed to become attached to like parts of the 

 pre-existing gene and so to arrive at the same arrangements as it has. There is a 



