Damer Combinatorial Selection in Fluctuating Hydrothermal Pools Origin of Cellular Life
<p>Oct 18, 2016 10:22 PM</p>
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Hydrothermal fields on the prebiotic Earth are candidate environments for biogenesis. </p>
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We propose a model in which molecular systems driven by <b>cycles of hydration and dehydration</b> in such sites undergo chemical evolution in dehydrated films on mineral surfaces followed by encapsulation and combinatorial selection in a hydrated bulk phase. </p>
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The dehydrated phase can consist of concentrated eutectic mixtures or multilamellar liquid crystalline matrices.</p>
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Both conditions <b>organize and concentrate potential monomers</b> and thereby promote polymerization reactions that are driven by reduced water activity in the dehydrated phase.</p>
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In the case of multilamellar lipid matrices, polymers that have been synthesized are captured in lipid vesicles upon rehydration to produce a variety of molecular systems. Each vesicle represents a protocell, an “experiment” in a natural version of combinatorial chemistry.</p>
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Two kinds of selective processes can then occur. The first is a physical process in which relatively stable molecular systems will be preferentially selected. The second is a chemical process in which rare combinations of encapsulated polymers form systems capable of capturing energy and nutrients to undergo growth by catalyzed polymerization.</p>
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Given continued cycling over extended time spans, such combinatorial processes will give rise to molecular systems having the fundamental properties of life.</p>