Towards molecular evolution with thermal traps

Live evolves by replication and selection of nucleotide polymers. Our experiments aim to drive molecular replication and selection with physical nonequilibrium boundary conditions. We discuss three approaches. Replication Trap. Molecules are exponentially accumulated by a combination of thermophoresis and convection, driven both by the same thermal gradient [1]. We have shown last year that with the help of a polymerase protein, concurrent replication and accumulation is possible [2]. Convection is melting and annealing the DNA in an oscillatory pattern, doubling the DNA in each cycle. Trapped polymerization. The chemical equilibrium of polymerization is expected to shift in the thermal trap. As the trap accumulates the monomers, polymerization yields longer polymers. However, since the trap is exponentially length selective, distributions beyond exponential tails are predicted. Replication by selective degradation. Replication typically is discussed as template directed polymerization. We showed that selective degradation and a thermal trap leads to replication-like behavior using only non templated polymerization [3]. The progression of information is given by the faster degradation of single stranded over double stranded RNA. [1] PNAS 104, 9346 (2007) [2] PRL 104, 188102 (2010) [3] PRL 107, 018101 (2011)