Berlin 2012 – scientific programme

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BP: Fachverband Biologische Physik

BP 30: Symposium SYOL: Origin of Life (with CPP and DY)

BP 30.3: Invited Talk

Friday, March 30, 2012, 10:30–11:00, H 0105

Thermal solutions for molecular evolution — •Dieter Braun — Systems Biophysics, Physics Department, Center for Nanoscience, LMU Munich, Germany

Disequilibrium conditions are central for understanding the origin of life. Taking energetic chemicals at high concentrations to synthesize more complex molecules will not be enough to understand early molecular evolution.

Thermal gradients drive two processes. Laminar thermal convection leads to highly regular temperature oscillations that allow the melting and protein-based replication of DNA. In the same setting, molecules move along the thermal gradient (Soret effect), leading with thermal convection to strong accumulation of biomolecules. More complex molecules are exponentially better retained.

Our experiments implement both replication and accumulation in a micrometer-sized chamber. The setting offers an elegant implementation of a Darwinian process of replication and selection that is solely driven by a thermal gradient.

Early replication however has to be implemented without proteins. We demonstrate that a pool of Transfer RNA yields a protein-free route to replication and translation. In addition, Obermayer and Gerland showed that replication-like behavior is already found by selective degradation of single over double stranded RNA. If combined with a length selective thermophoretic trap, complex dynamics are expected. As a first indication, we found the enhanced polymerization of nucleotides in a thermophoretic trap.