Genie and Non-genic Parts of the Chromosome 41 



scribed. Such a function of the stiff DNA fiber was frequently 

 assumed for former models of this material. It includes as a corollar\" 

 the idea that self-duplication is a property" of the nucleoprotein com- 

 bination. An explanation of how it occurs for the nucleic acid moiet>' 

 can therefore be made to include self-duphcation of the proteinic 

 molecule working together with its DXA scaffolding. Thus we are 

 still left without a proof that DXA is the genie material, alluring as 

 the new model is. 



Now we come to the decisive point, which Watson and Crick 

 more or less wave aside, namely, how to bridge the gap between the 

 DXA molecule and the self-duplicating chromosome with all its 

 constituent parts, \isible and biochemical. If DXA is the genie ma- 

 terial because the structure of the molecule permits self-dupHcation, 

 we see only t\vo possibilities: (1) either the entire chromosome is a 

 single giant DXA molecule to which proteins are attached and 

 passively di\"ided with the DXA chain or temporarily removed and 

 attached again in some way, which is not relevant for the actual 

 genie material; or (2) the DXA molecule is the gene in a chromomere 

 which dupHcates in the proposed way, lea\-ing us to explain how 

 the entire chromosome duplicates (perhaps in a haphazard way by 

 accretion and fission?). Either way, there is no possibiht)' of genie 

 function of the DX'A molecule unless it serves as a template for the 

 primary gene products, which may be RXA in part but certainly also 

 enz\-mes (i.e., proteins). Thus nothing is gained by the assumption 

 of genie properties of DXA, compared with its acting as a scaffold 

 for the duphcation of protein molecules, N^-ith which DXA is always 

 associated. It is certain that the self-duphcating double structure goes 

 far toward satisfying our requirements for the nature of the genie 

 material. But the beaut>' of the concept should not obscure the fact 

 that, when seeking to determine the relative role of DXA within 

 the whole of the chromosome, we are confronted again with the 

 DNA-protein combination and the probabiht)- that the self-duph- 

 cating DXA is only the prop for the real, proteinic genie material, 

 though the integral prop. Further, it should be emphasized that there 

 are many self-duplicating structures which are certainly free of DXA: 

 centrioles, kinetics, and all the specific protein molecules in the cell. 

 It is unkno\%-n whether, at the moment of their dupHcation. RXA is 

 present. Brachet's work intimates that RXA may actually be needed 

 for all c>toplasmic s\Titheses. Such ideas are some of the reasons 

 why all the self-duphcating elements in the cell are frequently called 

 genes (e.g., plasmagenes ) . These are problems for later discussion, 



