Biogenesis and the Growth of DNA-Like Polymer Chains: A Computer Simulation.

摘要

We study, through computer simulation, a crucial step of Biogenesis, namely the growth of self-replicating codified DNA-like polymers starting from a mixture of oligomers. We have adopted the growth scheme that has been recently proposed by Ferreira and Tsallis which incorporates usual ideas of autocatalysis through complementary pairs and within which a central role is played by the hydrogen-like links (characterized by the probabilities p/sub AT/ and p/sub CG/ of chemical bonding of the A-T and C-G pairs respectively) between the two chains of the growing polymer. We find that the average equilibrium polymeric length xi diverges, for any fixed ratio (1-p/sub AT/)/(1-p sub (CG)), as xi proportional to 1/r1-p/sub AT/. Selection of patterns may happen at all stages and in particular at chemical equilibrium. Selection occurs via two different mechanisms: (i) away from the critical point p/sub AT/ = p/sub CG/ = 1 if p/sub AT/ not = p/sub CG/; (ii) both on and away from the critical point if the initial concentrations of nucleotides (A, T, C and G or their precursors) are different. (Atomindex citation 19:064270)