Oro: Experimental Organic Cosmochemistry 477 



iminyl phosphate, obtained by condensation of hydrogen cyanide with mono- 

 hydrogen phosphate, is suggested here as another possibiUty of a primitive 

 high energy phosphate compound. More recently, Schramm et al.,^'^ have 

 shown that mononucleosides, mononucleotides, and polynucleotides can be 

 synthesized at moderate temperatures, from their building monomeric blocks, 

 with the help of polyphosphate esters. The polymers obtained seem to have 

 the v3',5'-phosphate diester linkages which are common to RNA and DNA. 

 Strand complementarity, which is the principle of molecular self duplication, 

 and autocatalytic activity, have also been observed in the above polynucleo- 

 tides. The role that nucleic acids and other macromolecules may have played 

 in directing prebiochemical evolution has been discussed in some detail by 

 several authors.'''^ •^^*"^*'' 



Conclusion 



There is no doubt that carbon compounds exist widely distributed in the 

 universe. Whether the more complex biochemical compounds described in 

 this paper are present in cosmic bodies other than the earth will only be 

 answered with certainty by space probes. Probes to the moon. Mars, and 

 Venus are feasible and should provide valuable information about the organic 

 and inorganic chemistry in these bodies. However, more information about 

 the chemistry prevailing during the beginning of the solar system would be 

 obtained by sending probes to Jupiter and to comets passing sufficiently close 

 to the earth's orbit. 



From the experimental studies presented here it is reasonable to say that if 

 the Earth protoplanet had some of the simple organic constituents of comets, 

 a large number of biochemical compounds (including carbohydrates, amino 

 acids, purines, pyrimidines, and polymers containing amino acids) would have 

 been spontaneously synthesized during the development of this cosmic body. 



The formation of complex biochemical compounds from simple organic mole- 

 cules is not in disagreement with thermodynamic principles. In fact, these 

 syntheses can occur because the initial precursors (nitriles, aldehydes, olefins, 

 etc.) are compounds of high energy content which, in their tendency to acquire 

 lower energy states and to become stabilized, react and are ipso facto trans- 

 formed into biochemical compounds. 



The possibility that organic chemical synthesis may have occurred in inter- 

 stellar dust and planetesimal bodies before the Earth was formed has also been 

 suggested by Lederberg and Cowie^^' and Fowler, Greenstein and Hoyle.^^^ 



Acknowledgment 



Some of the work from our laboratory reported in this paper was supported 

 in part by research grants from the National Science Foundation (G-13117) 

 and the National Aeronautics and Space Administration (NsG-257-62). 



References 



1. Aller, L. H. 1961. The Abundance of the Elements. Interscience Publishers. 



New York. 



2. SuESS, H. E. & H. C. Urey. 1956. Rev. Modern. Phys. 28: 53. 



3. VON Kluber, H. 1931. Das vorkommen der chemischen Elemente ini Kosmos. J. A. 



Barth. Leipzig. 



4. Greenstein, J. L. 1961. Am. Scientist. 49: 449. 



