Nucleic acids oxidation, principles

H2. The H2 would diffuse out of Earth s atmosphere. Even in these less reducing atmospheres (e.g., CO and CO2 instead of CH4, N2 instead of NH3), Miller-type experiments yield amino acids, nucleic acid bases, and simple sugars. However, such syntheses do not occur in the presence of molecular oxygen (O2) and the principle holds prebiotic synthesis requires a reducing atmosphere and is not possible in Earth s current oxidizing atmosphere. 

That said, metabolic interconversion of the amine backbone linkage of the ANPs would require oxidation, and thus would be a redox process rather than condensation/hydrolysis. Water remains a necessity for life and certainly life on Earth exploits condensation in the linkages of the nucleic acid monomers (phosphoester bonds), the amides of polypeptides, and the acetals of polysaccharides, and utilizes the reverse reaction of hydrolysis for metaboUsm. Therefore we have sought to extend the principles learned with the amine backbones to possible backbone chemistries that allow equilibrium control of template-directed polymerization through condensation and hydrolysis reactions. 

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