Volume 8, Number 3, p.p. 89–93
DNA as a Darwinian self-replicator
Philippa M. Wiggins
Department of Medicine, University of Auckland and Genesis Research and Development Corporation, Auckland, New Zealand
At charged silicates in clays, counterions generate local osmotic pressure gradients. These act as pressure gradients, converting water containing the counterion into high density water (HDW) and water in an adjacent zone into low density water (LDW). Starting with a pool of racemic nucleotides, in such a clay multiple copies of double stranded DNA are the end-point of the following series of spontaneous reactions: (1) D-nucleotides accumulate into LDW and polymerize; (2) L-nucleotides accumulate into HDW and do not polymerize; (3) a single strand of D-oligonucleotides joined with covalent bonds is released into bulk water; (4) complementary nucleotides hydrogen-bond to the strand; (5) the strand plus its hydrogen-bonded nucleotides diffuses into another pocket of LDW; (6) covalent bonds form between adjacent hydrogen-bonded nucleotides; (7) hydrogen bonds between nucleotides collapse to give two separate strands, each joined with covalent bonds; and (8) the two separate strands are released into bulk water. Steps 1 to 8 iterate with hydrogen bonds forming in bulk water and covalent bonds forming and hydrogen bonds collapsing in LDW at the silicate sites, until there are enough single strands to enable whole strands to hydrogen-bond with each other. The double strands then decrease their surface area by forming double helices.
Keywords:
evolution, nucleotides, primordial clays, water