Emergence of Life on Earth: A Physicochemical Jigsaw Puzzle

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• 作者：Jan Spitzer
• 关键词：Earth–Moon system ; Cyclic environments ; Colloidal phase separations ; Confinement ; Macromolecular crowding ; Non ; covalent molecular forces ; Progenotes ; Emergence ; Life
• 刊名：Journal of Molecular Evolution
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：84
• 期：1
• 页码：1-7
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Evolutionary Biology; Microbiology; Plant Sciences; Plant Genetics & Genomics; Animal Genetics and Genomics; Cell Biology;
• 出版者：Springer US
• ISSN：1432-1432
• 卷排序：84

文摘

We review physicochemical factors and processes that describe how cellular life can emerge from prebiotic chemical matter; they are: (1) prebiotic Earth is a multicomponent and multiphase reservoir of chemical compounds, to which (2) Earth–Moon rotations deliver two kinds of regular cycling energies: diurnal electromagnetic radiation and seawater tides. (3) Emerging colloidal phases cyclically nucleate and agglomerate in seawater and consolidate as geochemical sediments in tidal zones, creating a matrix of microspaces. (4) Some microspaces persist and retain memory from past cycles, and others re-dissolve and re-disperse back into the Earth’s chemical reservoir. (5) Proto-metabolites and proto-biopolymers coevolve with and within persisting microspaces, where (6) Macromolecular crowding and other non-covalent molecular forces govern the evolution of hydrophilic, hydrophobic, and charged molecular surfaces. (7) The matrices of microspaces evolve into proto-biofilms of progenotes with rudimentary but evolving replication, transcription, and translation, enclosed in unstable cell envelopes. (8) Stabilization of cell envelopes ‘crystallizes’ bacteria-like genetics and metabolism with low horizontal gene transfer—life ‘as we know it.’ These factors and processes constitute the ‘working pieces’ of the jigsaw puzzle of life’s emergence. They extend the concept of progenotes as the first proto-cellular life, connected backward in time to the cycling chemistries of the Earth–Moon planetary system, and forward to the ancient cell cycle of first bacteria-like organisms. Supra-macromolecular models of ‘compartments first’ are preferred: they facilitate macromolecular crowding—a key abiotic/biotic transition toward living states. Evolutionary models of metabolism or genetics ‘first’ could not have evolved in unconfined and uncrowded environments because of the diffusional drift to disorder mandated by the second law of thermodynamics.