scholarly journals A network theory of the origin of life

2016 ◽  
Author(s):  
Geoffrey W. Hoffmann
Keyword(s):  
Origin Of Life ◽  
Network Theory ◽  
High Probability ◽  
Volcanic Ash ◽  
Large Fraction ◽  
Nucleation Event ◽  
Primitive Earth ◽  
Low Probability ◽  
The Origin Of Life ◽  
Non Coding Rnas

AbstractThe origin of life may have been a low probability event that involved both RNA and polypeptides. While such an event would occur with low probability, the probability is not too low in the context of the number of nucleation opportunities on the primitive Earth. The probability for the nucleation event is too small if needed components occur as frequently as disruptive components do, without specific interactions between the two classes. However, if many of the needed components contribute by inhibiting otherwise disruptive components, a high probability for a complex nucleation as the beginning of life event emerges. RNA interference and long non-coding RNAs are ascribed roles in inhibiting components that would otherwise be disruptive in the context of a nucleation event. The theory likewise provides an inhibitory role for the large fraction of proteins (35% to 40%) that have no known function in both prokaryotes and eukaryotes. It is suggested that volcanic ash could provide the large number of random shapes needed as the basis for the nucleation event. Experiments based on that hypothesis are proposed.

A biointerface effect on the self-assembly of ribonucleic acids: a possible mechanism of RNA polymerisation in the self-replication cycle

Nanoscale ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 6691-6698 ◽  
Author(s):  
Noriyoshi Arai ◽  
Yusei Kobayashi ◽  
Kenji Yasuoka
Keyword(s):  
Cell Membrane ◽  
Origin Of Life ◽  
Self Assembly ◽  
Replication Cycle ◽  
The Self ◽  
Primitive Earth ◽  
Ribonucleic Acids ◽  
Bulk System ◽  
The Origin Of Life ◽  
Self Replication

The self-assembly was found to be more favoured in a vesicle-cell membrane, rather than in the bulk system. The result will contribute to a better understanding of the origin of life on the primitive Earth.

scholarly journals Montmorillonite-catalysed formation of RNA oligomers: the possible role of catalysis in the origins of life

2006 ◽  
Vol 361 (1474) ◽  
pp. 1777-1786 ◽  
Author(s):  
James P Ferris
Keyword(s):  
Origin Of Life ◽  
Volcanic Ash ◽  
Origins Of Life ◽  
Reaction Conditions ◽  
The Earth ◽  
Rna Oligomers ◽  
The Origin Of Life ◽  
Large Deposits

Large deposits of montmorillonite are present on the Earth today and it is believed to have been present at the time of the origin of life and has recently been detected on Mars. It is formed by aqueous weathering of volcanic ash. It catalyses the formation of oligomers of RNA that contain monomer units from 2 to 30–50. Oligomers of this length are formed because this catalyst controls the structure of the oligomers formed and does not generate all possible isomers. Evidence of sequence-, regio- and homochiral selectivity in these oligomers has been obtained. Postulates on the role of selective versus specific catalysts on the origins of life are discussed. An introduction to the origin of life is given with an emphasis on reaction conditions based on the recent data obtained from zircons 4.0–4.5 Ga.

scholarly journals The origin of life

1988 ◽  
Vol 7 (1) ◽  
pp. 33-37
Author(s):  
W. Van Hoven
Keyword(s):  
Amino Acids ◽  
Twentieth Century ◽  
Origin Of Life ◽  
Organic Compounds ◽  
Big Bang ◽  
Natural Process ◽  
Primitive Earth ◽  
The Origin Of Life ◽  
Life On Earth ◽  
The Big Bang

For many centuries scientists have been debating the question of how life on earth originated. With the increase in knowledge and technology in the twentieth century, realistic explanations are around with regard to the nature of life and its origin. One thought is that life has always existed, while a thought which is discussed deals with life originating as a slow and natural process following the big bang. Long after the big bang primitive earth formed, followed by the formation of prebiotic organic compounds. As these compounds became more concentrated they reacted spontaneously into elementary precursors of life such as amino acids and proteins.

scholarly journals The origin of life as a probabilistic event in the Universe

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Dimitri Marques Abramov ◽  
Carlos Alberto Mourão Júnior
Keyword(s):  
Mathematical Model ◽  
Origin Of Life ◽  
Realistic Model ◽  
Primitive Earth ◽  
Nanoarchaeum Equitans ◽  
The Origin Of Life ◽  
Chemical Conditions ◽  
The Universe ◽  
Information Amount ◽  
The Ideal

By means of a probabilistic mathematical model, we bring into discussion the origin of life as a stochastic process. We consider only the chance of information emergence in the proteome and genome under the ideal thermodynamic and chemical conditions. For a more realistic model, we used, as a parameter, the information amount in Nanoarchaeum equitans genome, the simplest known nowadays, as the equivalent to the first living cell that could have emerged in primitive Earth. We estimated the probability of information emergence by chance as about 10-500’000. Considering the necessary ideal conditions for information emergence, the probability of the origin of life would be even smaller.

The Tempo and mode(S) of Prebiotic Evolution

1997 ◽  
Vol 161 ◽  
pp. 419-429 ◽  
Author(s):  
Antonio Lazcano
Keyword(s):  
Origin Of Life ◽  
Organic Compounds ◽  
Biological Evolution ◽  
Current Evidence ◽  
Early Diversification ◽  
Time Period ◽  
The Galaxy ◽  
History Of ◽  
Widespread Phenomenon ◽  
The Origin Of Life

AbstractDifferent current ideas on the origin of life are critically examined. Comparison of the now fashionable FeS/H2S pyrite-based autotrophic theory of the origin of life with the heterotrophic viewpoint suggest that the later is still the most fertile explanation for the emergence of life. However, the theory of chemical evolution and heterotrophic origins of life requires major updating, which should include the abandonment of the idea that the appearance of life was a slow process involving billions of years. Stability of organic compounds and the genetics of bacteria suggest that the origin and early diversification of life took place in a time period of the order of 10 million years. Current evidence suggest that the abiotic synthesis of organic compounds may be a widespread phenomenon in the Galaxy and may have a deterministic nature. However, the history of the biosphere does not exhibits any obvious trend towards greater complexity or «higher» forms of life. Therefore, the role of contingency in biological evolution should not be understimated in the discussions of the possibilities of life in the Universe.

Photochemical Evolution of Interstellar/Precometary Organic Material

1997 ◽  
Vol 161 ◽  
pp. 23-47 ◽  
Author(s):  
Louis J. Allamandola ◽  
Max P. Bernstein ◽  
Scott A. Sandford
Keyword(s):  
Origin Of Life ◽  
Building Blocks ◽  
Complex Species ◽  
Infrared Observations ◽  
Interstellar Ice ◽  
Polycyclic Aromatic ◽  
Ultraviolet Photolysis ◽  
The Origin Of Life ◽  
Simple Molecules ◽  
Complex Organic

AbstractInfrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Since comets are thought to be a major source of the volatiles on the primative earth, their organic inventory is of central importance to questions concerning the origin of life. Ices in molecular clouds contain the very simple molecules H2O, CH3OH, CO, CO2, CH4, H2, and probably some NH3and H2CO, as well as more complex species including nitriles, ketones, and esters. The evidence for these, as well as carbonrich materials such as polycyclic aromatic hydrocarbons (PAHs), microdiamonds, and amorphous carbon is briefly reviewed. This is followed by a detailed summary of interstellar/precometary ice photochemical evolution based on laboratory studies of realistic polar ice analogs. Ultraviolet photolysis of these ices produces H2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(= O)NH2(formamide), CH3C(= O)NH2(acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including polyoxymethylene and related species (POMs), amides, and ketones. The ready formation of these organic species from simple starting mixtures, the ice chemistry that ensues when these ices are mildly warmed, plus the observation that the more complex refractory photoproducts show lipid-like behavior and readily self organize into droplets upon exposure to liquid water suggest that comets may have played an important role in the origin of life.

Spatial suppression due to statistical regularities is driven by distractor suppression not by target activation

2018 ◽  
Author(s):  
Michel Failing ◽  
Benchi Wang ◽  
Jan Theeuwes
Keyword(s):  
High Probability ◽  
Target Location ◽  
Target Selection ◽  
Visual Space ◽  
Alternative Interpretation ◽  
Distractor Location ◽  
Target Presentation ◽  
Statistical Regularities ◽  
Low Probability ◽  
Presentation Experiment

Where and what we attend to is not only determined by what we are currently looking for but also by what we have encountered in the past. Recent studies suggest that biasing the probability by which distractors appear at locations in visual space may lead to attentional suppression of high probability distractor locations which effectively reduces capture by a distractor but also impairs target selection at this location. However, in many of these studies introducing a high probability distractor location was tantamount to increasing the probability of the target appearing in any of the other locations (i.e. the low probability distractor locations). Here, we investigate an alternative interpretation of previous findings according to which attentional selection at high probability distractor locations is not suppressed. Instead, selection at low probability distractor locations is facilitated. In two visual search tasks, we found no evidence for this hypothesis: neither when there was only a bias in target presentation but no bias in distractor presentation (Experiment 1), nor when there was only a bias in distractor presentation but no bias in target presentation (Experiment 2). We conclude that recurrent presentation of a distractor in a specific location leads to attentional suppression of that location through a mechanism that is unaffected by any regularities regarding the target location.

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