The Origin of Life 19 



One can well imagine that this system is a far cry from the first 

 system of transmitting genetic information. For example, its 

 sophistication may be seen in the fact that the DNA remains as a 

 master template, reducing the possibilities for error that would be 

 inherent in a system in which copies are made from copies. Similarly, 

 the short transfer RNA molecules are highly specialized to accom- 

 plish the proper positioning of the protein precursors. The manifold 

 interactions of DNA and RNA in the organism are not confined to 

 processes concerning transmission of genetic information and protein 

 synthesis. There is speculation that RNA functions in those higher- 

 organism systems that involve training and memory. The mental 

 properties of primates may eventually be described in terms of 

 fundamental chemical properties recognizable in the simplest cells 

 and organisms. 



In viewing the complexities of function found in the cells of 

 present-day organisms— the highly specialized organelles, the very 

 efficient system for utilizing high-energy phosphate bonds, the pre- 

 cise mechanisms for distribution of genetic information and for cell 

 division— one may find it hard to believe that such complexity ever 

 arose from the coacervate stage previously described. It is like look- 

 ing at a unicellular organism and a man and trying to imagine one 

 as the ancestor of the other without knowledge of any intermediates. 

 It should be remembered that the time available for the evolution 

 of the coacervate into the complex cell was of the same magnitude 

 as that available for the journey from protistan to man. 



SUMMARY 



Life is a complex energy-matter nexus whose origin can be ex- 

 plained logically in general terms. Important events in the origina- 

 tion of life certainly were the development of organic compounds, 

 their segregation into structural entities, the origin of energy-mobiliz- 

 ing cycles, and the development of systems for self-replication. 

 These events presumably must have been partially synchronous 

 and were controlled by a sort of protoselection. The present system 

 for self-replication utilizes information coded in macromolecules of 

 nucleic acids that control protein synthesis. 



Life may be considered to be an aspect of the matter-energy con- 

 tinuum characterized by incessant replication. Perfect replication 

 is impossible, and therefore natural selection is inevitable. 



