Novel Apparatuses for Incorporating Natural Selection Processes into Origins-of-Life Experiments to Produce Adaptively Evolving Chemical Ecosystems

Abstract

Origins-of-life chemical experiments usually aim to produce specific chemical end-products such as amino acids, nucleic acids or sugars. The resulting chemical systems do not evolve or adapt because they lack natural selection processes. We have modified Miller origins-of-life apparatuses to incorporate several natural, prebiotic physicochemical selection factors that can be tested individually or in tandem: freezing-thawing cycles; drying-wetting cycles; ultraviolet light-dark cycles; and catalytic surfaces such as clays or minerals. Each process is already known to drive important origins-of-life chemical reactions such as the production of peptides and synthesis of nucleic acid bases and each can also destroy various reactants and products, resulting selection within the chemical system. No previous apparatus has permitted all of these selection processes to work together. Continuous synthesis and selection of products can be carried out over many months because the apparatuses can be re-gassed. Thus, long-term chemical evolution of chemical ecosystems under various combinations of natural selection may be explored for the first time. We argue that it is time to begin experimenting with the long-term effects of such prebiotic natural selection processes because they may have aided biotic life to emerge by taming the combinatorial chemical explosion that results from unbounded chemical syntheses.

Setting the geological scene for the origin of life and continuing open questions about its emergence

“…A recently-created consortium of researchers seeking to understand the origins of life on Earth and in the Universe will hopefully advance the field ( Müller et al, 2022 ). Novel apparatuses for incorporating natural selection processes have been also proposed ( Root-Bernstein and Brown, 2022 ).…”

“Sea Water” Supplemented with Calcium Phosphate and Magnesium Sulfate in a Long-Term Miller-Type Experiment Yields Sugars, Nucleic Acids Bases, Nucleosides, Lipids, Amino Acids, and Oligopeptides

“…Iron complexes have also been implicated in the production and breakdown of universal metabolic precursor compounds [ 31 ]. A listing of the many other mineral catalysts of prebiotic reactions would be too long to include here, but some representative publications include [ 33 , 34 , 35 , 36 ], and a brief review can be found in [ 37 ]. More complex atmospheres (including CO 2 , CO, H 2 S, NO, etc.)…”

“…Much longer experiments should also be performed to determine whether it is possible to produce more and longer peptides, di- and polysaccharides, di- and polynucleic acids, etc. We also believe that additional energy sources, such as ultraviolet light cycles, freeze–thaw cycles, wet–dry cycles, etc., should be introduced into these “dirty” experiments not only to drive novel reactions but also to act as selective agents to limit the chemical combinatorial explosion that can, otherwise, be expected to result [ 37 ].…”

Could Life Have Started on Mars? Planetary Conditions That Assemble and Destroy Protocells

“…Most research on the origin of life has focused on early Earth environments, such as hydrothermal deep-sea vents and hot springs locations where specific organic molecules sequestered by cellular life on Earth can be found and form structures resembling primitive cells [ 7 , 8 , 9 , 10 , 11 ]. Related approaches explain evolution towards life in chemistry by focusing on self-organization (e.g., [ 12 , 13 ]), prebiotic natural selection(e.g., [ 7 , 14 , 15 , 16 ]), molecular self-replication, auto-catalysis, and dynamic kinetic stability (e.g., [ 17 , 18 , 19 , 20 , 21 , 22 ]), more broadly. Additionally, advances in theoretical origin-of-life research provide frameworks that characterize fundamental life processes, expanding origin-of-life models from the origin of cells to the origin of information, selection, complexity, and evolution (e.g., [ 23 , 24 , 25 , 26 ]).…”

“…However, the degree of change in Martian planetary conditions over time may have been an adaptive challenge too great for even well-established cellular life to endure. 024, 14,415 in Martian planetary conditions over time may have been an adaptive challenge too g even well-established cellular life to endure. .…”