123 



SUMMARY 



What is the simplest chemical system that is capable of com- 

 plete genetic self-replication and open-ended Darwinian evolution? 

 This question has been at the heart of our discussion of the origin of 

 life. Experiments designed to demonstrate true self-replication and 

 natural selection in prebiotic situations, although perhaps a distant 

 goal, are of obvious value. Three experimental systems which might 

 conceivably lead to such a demonstration are nonenzymatic nucleic- 

 acid replication, clay replication, and combined peptide/nucleic acid 

 systems. Although none of these systems has demonstrated all of the 

 characteristics for self-replication, each has promise worth pursuing. 



Another possible route to demonstrate self-replication and 

 natural selection, although without addressing the origin of such a 

 system, is to try to construct a minimal self-replicating system from 

 components of biological cells. This would indeed be worthwhile if it 

 could be done, since it would to some extent plug the huge concep- 

 tual gap between simple self-replicating systems and the complex 

 genetic system of even the simplest contemporary cell. 



In summary, the most critical need in the areas of nucleic-acid 

 replication, translation, and other aspects of self-replicating systems 

 is for experimental studies rather than more speculations and diffuse 

 theories. 



NEXT ORGANIZATIONAL STEPS 



This whole report has sought to sum up the present state of our 

 knowledge and the questions which remain, the many small ques- 

 tions whose answers will lead us to see into the great question, so 

 important for most reflective people, scientists or not. 



A modest world community — a few scores of laboratories and 

 a thousand or two scientific workers — will encounter great difficulty 

 in its pursuit of this very important question. People in such a com- 

 munity work with a given discipline; they are geochemists, or micro- 

 biologists or nucleic acid chemists, or biochemists, or specialists in 

 planetary dynamics. The classes they teach, the techniques they use, 

 the meetings they attend, the journals they read and contribute to, 



