Origin and persistence of genetic material in prebiotic habitats
Molecules which store genetic information (RNA, DNA) are central
to all life on earth. The formation of these complex molecules required specific
conditions, including the synthesis of precursors (nucleotides), the joining
of these monomers into larger molecules (polynucleotides), their protection
from degradation, and the expression of the biological potential of the informative
molecule, which is its capacity to multiply and evolve. Determining how these
steps occurred and how the earliest genetic molecules originated on Earth is
a problem that is far from being resolved. Classical research in this field
has focused on process in aqueous solution. However, it is difficult to believe
that complex molecules can be obtained by random collisions in a fully aqueous
environment since under these conditions, hydrolysis and not polymerization
if favoured. We believed that it is crucial to consider surface organic chemistry.
As early as 1951, J.D. Bernal suggest, on the basis of thermodynamic and kinetic
considerations, that mineral surfaces (specifically clay minerals) could have
played an important role in the prebiotic formation of the biomolecules basic
to life.
In recent years, numerous observations in different fields, from astrophysical
chemistry to molecular biology, have reinforced the hypothesis of the involvement
of mineral surfaces in the prebiotic origin of life.