Genetics first or metabolism first? The formamide clue.
Life is made of the intimate interaction of metabolism and genetics, both built around the chemistry of the most common elements of the Universe (hydrogen, oxygen, nitrogen, and carbon). The transmissible interaction of metabolic and genetic cycles results in the hypercycles of organization and de-organization of chemical information, of living and non-living. The origin-of-life quest has long been split into several attitudes exemplified by the aphorisms "genetics-first" or "metabolism-first". Recently, the opposition between these approaches has been solved by more unitary theoretical and experimental frames taking into account energetic, evolutionary, proto-metabolic and environmental aspects. Nevertheless, a unitary and simple chemical frame is still needed that could afford both the precursors of the synthetic pathways eventually leading to RNA and to the key components of the central metabolic cycles, possibly connected with the synthesis of fatty acids. In order to approach the problem of the origin of life it is therefore reasonable to start from the assumption that both metabolism and genetics had a common origin, shared a common chemical frame, and were embedded under physical-chemical conditions favourable for the onset of both. The singleness of such a prebiotically productive chemical process would partake of Darwinian advantages over more complex fragmentary chemical systems. The prebiotic chemistry of formamide affords in a single and simple physical-chemical frame nucleic bases, acyclonucleosides, nucleotides, biogenic carboxylic acids, sugars, amino sugars, amino acids and condensing agents. Thus, we suggest the possibility that formamide could have jointly provided the main components for the onset of both (pre)genetic and (pre)metabolic processes. As a note of caution, we discuss the fact that these observations only indicate possible solutions at the level of organic substrates, not at the systemic chemical level.
Dipartimento di Agrobiologia ed Agrochimica, Università della Tuscia, Via San Camillo De Lellis, 01100 Viterbo, Italy. saladino@unitus.it
Raffaele
R
Saladino
Giorgia
G
Botta
Samanta
S
Pino
Giovanna
G
Costanzo
Ernesto
E
Di Mauro
D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism; D002264:Carboxylic Acids / Q000737:chemistry / Q000378:metabolism; D019418:Evolution, Chemical; D005559:Formamides / Q000737:chemistry* / Q000378:metabolism*; D006856:Hydrogen Cyanide / Q000737:chemistry; D053858:Metabolic Networks and Pathways; D008903:Minerals / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D009696:Nucleic Acids / Q000737:chemistry / Q000378:metabolism; D000069497:Origin of Life; D058105:Polymerization
D000596:Amino Acids; D002264:Carboxylic Acids; D005559:Formamides; D008903:Minerals; D009696:Nucleic Acids; D006856:Hydrogen Cyanide; C031066:formamide