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BP: Fachverband Biologische Physik
BP 24: Synthetic life-like systems and Origins of Life
BP 24.2: Talk
Wednesday, March 20, 2024, 15:30–15:45, H 1028
Sequence self-selection by cyclic phase separation — •Philipp Schwintek1, Giacomo Bartolucci2, Adriana Calaca Serrao1, Dieter Braun1, Christof Weber2, Alexandra Kühnlein1, Yasha Rana2, Philipp Janto1, Dorothea Hofer1, and Christof Mast1 — 1Ludwigs-Maximilian-Universität München and Center for NanoScience, Munich 80799, Germany — 2Division Biological Physics, Max Planck Institute for the Physics of Complex Systems, Dresden 01187, Germany
The emergence of functional oligonucleotides on early Earth required a molecular selection mechanism to screen for specific sequences with prebiotic functions. Cyclic processes such as daily temperature oscillations were ubiquitous in this environment and could trigger oligonucleotide phase separation. Here, we propose sequence selection based on phase separation cycles realized through sedimentation in a system subjected to the feeding of oligonucleotides. Using theory and experiments with DNA, we show sequence-specific enrichment in the sedimented dense phase, in particular of short 22-mer DNA sequences. The underlying mechanism selects for complementarity, as it enriches sequences that tightly interact in the dense phase through base-pairing. Our mechanism also enables initially weakly biased pools to enhance their sequence bias or to replace the previously most abundant sequences as the cycles progress. Our findings provide an example of a selection mechanism that may have eased screening for auto-catalytic self-replicating oligonucleotides.
Keywords: phase-separation; selection; DNA; sedimentation; prebiotic