Regensburg 2016 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 59: DNA, RNA and Related Enzymes
BP 59.3: Vortrag
Donnerstag, 10. März 2016, 10:15–10:30, H45
Accumulation and Replication in shallow thermal gradients: towards volcanic settings — •Michael Hartmann, Lorenz Keil, and Dieter Braun — Biophysics Department, Ludwig-Maximilians-Universität München, Amalienstraße 54, 80799 München, Germany
The most likely low concentration of molecules in a prebiotic ocean is a central problem for the origin of life. We have argued in the past that focused temperature gradients in hydrothermal, porous systems can thermophoretically accumulate, thermally cycle, and continuously feed the first prebiotic molecules for evolution [Mast, PRL 2010; Mast et al., PNAS 2013; Kreysing et al., Nature Chemistry 2015]. But the applied gradients of 10−100 K/mm limit the scope of the approach to hydrothermal orifices.
We simulate in silico that a strong molecular accumulation (of nucleotides in particular) more than 1020-fold still takes place in thermal gradients of 0.1 K/mm (100 K/m), about 100−1000 fold more shallow than considered before. Accumulations remain stable under various pore widths and tilt angles. We investigate the stochastic thermal cycling of single molecules by two-dimensional random walk in the convection.
With the findings, more shallow gradients in steam heated, porous volcanic rock can be considered. This is important since wet-dry cycles under UV illumination seem important for the generation of nucleotides [Powner et al., Nature 2009]. To conclude, the study expands the thermal gradient scenario for the onset of molecular evolution towards shallow thermal gradients.