ORIGINE DEL MATERIALE GENETICO SU PARTICELLE MINERALI Enzo Gallori DBAG- Università di Firenze

Erwin Schrödinger What is Life, 1944

The DNA Molecule Pu Py Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Phosphate Sugar Base Nucleotide

The Transition from Chemistry to Biology: Nucleic Acids (DNA, RNA) as Stores of Biological Information Complementary Base Pairing A = T G C Genetic Information A G AT GC T C DNA

The basic principle of biology Replication Transcription Genotype Traduction Phenotype

G A A G Perpetuation of Information A G T C A G T C T C T C Replication A G AT GC T C A G AT GC T C

Building Code Synthesis and accumulation of precursors (i.e. nucleotides) Joining of precursors into larger molecules (i.e. DNA, RNA) Protection from degradation Persistence Expression of biological potentiality of the informational molecule

Prebiotic Chemistry Synthesis and Accumulation of Precursors: A.I. Oparin (~1920) - J.B.S. Haldane (~1930) The Primordial Soup S.L. Miller (1953) Primordial Soup Refrigerator Electrodes

Cosmic radiation Molecules from Space Synthesis and Accumulation of Precursors: Amminoacids Ethers PAH N Bases ? H, CO, PAH Diffuse Clouds Ice : Core H CH CO PAH Dense Clouds Early Earth Comets Meteorites

Chemistry in Cosmic Dust Laboratory simulations ( L.J.Allamandola and coll., ) Water Carbon monoxide Carbon dioxide Methanol Hydrocarbon Silicate granule Ice Ketons Aminoacids Quinones N Bases? U.V. radiation

Building Code Synthesis and accumulation of precursors (i.e. nucleotides) Joining of precursors into larger molecules (i.e. DNA, RNA) Protection from degradation Persistence Expression of biological potentiality of the informational molecule

Ricerca classica: Chimica in soluzione acquosa Polimerizzazione In queste condizioni: è favorita lidrolisi e non la polimerizzazione. Chimica su superficie minerale Argille

J.D. Bernal (1951)... clays and other minerals were necessary to: 1) Concentrate the organics present in a dilute ocean by adsorption; 2) Protect these organics from destruction by U.V. light; 3) Catalyze the polymerization of adsorbed organics...

May catalyze the formation of oligonucleotides and peptides up to 50-mer long Ertem and Ferris (1996), Nature 379: Ferris et al. (1996), Nature 381: Joining of precursors into larger molecules: Mineral surfaces AC A T A G G T G C A C A

Nucleic acid-clay complexes RNA DNA Clay minerals: montmorillonite (M) kaolinite (K)

Electron Microscopy (T.E.M.) K-Chromosomal DNA (X 154,000) K-Plasmid DNA (X 271,500) Franchi et al., 1999, OLEB 29:

X-Ray Analysis of M-nucleic acid complexes Franchi et al., 1999, OLEB 29:

Role of cations in the adsorption of nucleic acids

FT-IR Analysis Franchi et al., 1999, OLEB 29:

Resistenza degli Acidi Nucleici adsorbiti allargilla La forrmazione dei dimeri di Timina è ridotta nel caso del DNA adsorbito allargilla Gallori et al., (2004) U.V. radiation K-Chromosomal DNA (X 154,000)

Did stone nurture the first life on earth?