Nucleobases on the Primitive Earth: Their Sources and Stabilities

Abstract

Nucleobases are nitrogen heterocycles that are key structural components of biological nucleic acids. Some theories for the origins of life suggest a role for environmentally supplied organic compounds, including nucleobases, as part of a primordial RNA or pre-RNA world. Over the last 65 years, many potentially prebiotic synthetic mechanisms have been experimentally demonstrated for nucleobases, and their presence in extraterrestrial materials has been extensively verified, suggesting some of these are valid explanations for how the environment produces them. However, the abundance of nucleobases in primitive environments would depend on the balance of the rates of their environmental synthesis and decomposition. The literature regarding chemical aspects of these questions is briefly reviewed here.