A mechanism of abiogenesis based on complex reaction networks organized by seed-dependent autocatalytic systems

The core of the origin-of-life problem is to explain how a complex dissipative system could emerge spontaneously from a simple environment, perpetuate itself, and complexify over time. This would only be possible, we argue, if prebiotic chemical reaction networks had autocatalytic features organized in a way that permitted the accretion of complexity even in the absence of genetic control. To evaluate this claim, we developed tools to analyze the autocatalytic organization of food-driven reaction networks and applied these tools to both abiotic and biotic networks. Both networks contained seed-dependent autocatalytic systems (SDASs), which are subnetworks that can use a flux of food chemicals to self-propagate if, and only if, they are first seeded by some non-food chemicals. Moreover, SDASs were organized such that the activation of a lower-tier SDAS could render new higher-tier SDASs accessible. The organization of SDASs is, thus, similar to trophic levels (producer, primary consumer, etc.) in a biological ecosystem. Furthermore, similar to ecological succession, we found that higher-tier SDASs may produce chemicals that enhance the ability of the entire chemical ecosystem to utilize food more efficiently. The SDAS concept explains how driven abiotic environments, namely ones receiving an ongoing flux of food chemicals, can incrementally complexify even without genetic polymers. This framework predicts that it ought to be possible to detect the spontaneous emergence of life-like features, such as self-propagation and adaptability, in driven chemical systems in the laboratory. Additionally, SDAS theory may be useful for exploring general properties of other complex systems.

Hydrothermal synthesis of long-chain hydrocarbons up to C24 with NaHCO3-assisted stabilizing cobalt

Abiotic CO2 reduction on transition metal minerals has been proposed to account for the synthesis of organic compounds in alkaline hydrothermal systems, but this reaction lacks experimental support, as only short-chain hydrocarbons (<C5) have been synthesized in artificial simulation. This presents a question: What particular hydrothermal conditions favor long-chain hydrocarbon synthesis? Here, we demonstrate the hydrothermal bicarbonate reduction at ∼300 °C and 30 MPa into long-chain hydrocarbons using iron (Fe) and cobalt (Co) metals as catalysts. We found the Co0 promoter responsible for synthesizing long-chain hydrocarbons to be extraordinarily stable when coupled with Fe−OH formation. Under these hydrothermal conditions, the traditional water-induced deactivation of Co is inhibited by bicarbonate-assisted CoOx reduction, leading to honeycomb-native Co nanosheets generated in situ as a new motif. The Fe−OH formation, confirmed by operando infrared spectroscopy, enhances CO adsorption on Co, thereby favoring further reduction to long-chain hydrocarbons (up to C24). These results not only advance theories for an abiogenic origin for some petroleum accumulations and the hydrothermal hypothesis of the emergence of life but also introduce an approach for synthesizing long-chain hydrocarbons by nonnoble metal catalysts for artificial CO2 utilization.

Dynamic Self-organization in an Open Reaction Network as a Fundamental Mechanism for the Emergence of Life

<p>The emergence of life on the earth has attracted intense attention but still remained an unsolved question. A key problem is that it has been left unclear why a living organism can have self-organizing ability leading to highly ordered structures and evolutionary behavior. This work reveals by computer simulation and experiments that a stationary state of an open reaction network, into which some source substances flow at constant rates, really has such self-organizing ability. The point is that reaction and diffusion processes in an open reaction network are irreversible and always forced to approach equilibrium. Therefore, they necessarily reach a stationary state in which they approach equilibrium to the largest extent as a whole and attain a full balance. This means that a stationary state of an open reaction network is firmly stabilized by irreversible reaction and diffusion processes and kept stable against fluctuation, namely it has ability to organize itself. A stationary state of an open reaction network is also flexible in structure and can evolve based on its own self-organizing ability through interaction with the environment. Thus, this work provides a new general mechanism of self-organization and evolution in a prebiotic chemical system, which is expected to have acted as a fundamental principle for the emergence of life on the earth. It is interesting to note that a network of reversible processes in a machine has no self-organizing ability because a reversible process has no property of spontaneously and irreversibly happening in a particular direction. </p>

Goals as Emergent Autopoietic Processes

While the phenomena of reaching a goal is generally represented in the framework of optimization, the phenomena of becoming of a goal is more similar to a “self-organization and emergent” rather than an “optimization and preexisting” process. In this article we provide a modeling framework for the former alternative by representing goals as emergent autopoietic structures. In order to conceptually situate our approach, we first review some of the most remarkable attempts to formally define emergence, and identify that in most cases such definitions rely on a preexisting system to be observed prior and post emergence, being thus inadequate for a formalization of emergent goals corresponding to the becoming of a systems as such (e.g. emergence of life). Next, we review how an implementation of the reaction networks framework, known as Chemical Organization Theory (COT), can be applied to formalize autopoietic structures, providing a basis to operationalize goals as an emergent process. We next revisit the definitions of emergence under the light of our approach, and demonstrate that recent taxonomies developed to classify different forms of emergence can be naturally deduced from recent work aimed to explain the kinds of changes of the organizational structure of a reaction network.

A mechanism of abiogenesis based on complex reaction networks organized by seed-dependent autocatalytic systems

The complexity gap between the biotic and abiotic worlds has made explaining abiogenesis one of the hardest scientific questions. A promising strategy for addressing this problem is to identify features shared by abiotic and biotic chemical systems that permit the stepwise accretion of complexity. Therefore, we compared abiotic and biotic reaction networks in order to evaluate the presence of autocatalysis, the underlying basis of biological self-propagation, and to see if the organization of autocatalytic motifs permits stepwise complexification. We provide an algorithm to detect seed-dependent autocatalytic systems (SDASs), namely subnetworks that can use food chemicals to self-propagate but must be seeded by some non-food chemicals to become activated. We show that serial activation of SDASs can cause incremental complexification. Furthermore, we identify life-like features that emerge during the accretion of SDASs, including the emergence of new ecological opportunities and improvements in the efficiency of food utilization. The SDAS concept explains how driven abiotic environments, namely ones receiving an ongoing flux of food chemicals, can incrementally complexify without the need for genetic polymers. This framework also suggests experiments that have the potential to detect the spontaneous emergence of life-like features, such as self-propagation and adaptability, in driven chemical systems.

A mechanism of abiogenesis based on complex reaction networks organized by seed-dependent autocatalytic systems

The complexity gap between the biotic and abiotic worlds has made explaining abiogenesis one of the hardest scientific questions. A promising strategy for addressing this problem is to identify features shared by abiotic and biotic chemical systems that permit the stepwise accretion of complexity. Therefore, we compared abiotic and biotic reaction networks in order to evaluate the presence of autocatalysis, the underlying basis of biological self-propagation, and to see if the organization of autocatalytic motifs permits stepwise complexification. We provide an algorithm to detect seed-dependent autocatalytic systems (SDASs), namely subnetworks that can use food chemicals to self-propagate but must be seeded by some non-food chemicals to become activated. We show that serial activation of SDASs can cause incremental complexification. Furthermore, we identify life-like features that emerge during the accretion of SDASs, including the emergence of new ecological opportunities and improvements in the efficiency of food utilization. The SDAS concept explains how driven abiotic environments, namely ones receiving an ongoing flux of food chemicals, can incrementally complexify without the need for genetic polymers. This framework also suggests experiments that have the potential to detect the spontaneous emergence of life-like features, such as self-propagation and adaptability, in driven chemical systems.

Can a Muslim be an Evolutionist?

I will argue that no claim about the emergence of life forms and humans can contradict Islam. Although the Quran clearly asserts that all species of life, including humans, are created by God, it does not reveal how God created. Since the Quran doesn’t teach how God created species, the Quran is compatible with evolution. Yet, although a Muslim can believe in evolution, I argue against the claim that a Muslim must accept evolution.

Evolutionary transition from a single RNA replicator to a multiple replicator network

In prebiotic evolution, self-replicating molecules are believed to have evolved into complex living systems by expanding their information and functions open-endedly. Theoretically, such evolutionary complexification could occur through successive appearance of novel replicators that interact with one another to form replication networks. Here we performed long-term evolution experiments using an RNA that replicates by a self-encoded RNA replicase. The RNA diversified into multiple coexisting host and parasite lineages, whose frequencies in the population initially fluctuated and gradually stabilized. The final population, comprising five RNA lineages, forms a replicator network with diverse interactions, including cooperation to help the replication of all other members. These results support the capability of molecular replicators to spontaneously develop complexity through Darwinian evolution, a critical step for the emergence of life.

FRONTIER RESEARCH IN ASTROPHYSICS IN THE GRAVITATIONAL WAVE ERA - II(EXOPLANETS AND EMERGENCE OF LIFE)

In this paper we will discuss exoplanets in the habitable zone of the Milky Way, the origin of terrestrial life, and what 'intelligent' humanity is doing, in order to complete the excursion on <i>The Bridge between the Big Bang and Biology</i>, started with the paper I (Giovannelli & Sabau-Graziati, 2020).

How the Geomagnetic Field Influences Life on Earth – An Integrated Approach to Geomagnetobiology

Earth is one of the inner planets of the Solar System, but – unlike the others – it has an oxidising atmosphere, relatively stable temperature, and a constant geomagnetic field (GMF). The GMF does not only protect life on Earth against the solar wind and cosmic rays, but it also shields the atmosphere itself, thus creating relatively stable environmental conditions. What is more, the GMF could have influenced the origins of life: organisms from archaea to plants and animals may have been using the GMF as a source of spatial information since the very beginning. Although the GMF is constant, it does undergo various changes, some of which, e.g. a reversal of the poles, weaken the field significantly or even lead to its short-term disappearance. This may result in considerable climatic changes and an increased frequency of mutations caused by the solar wind and cosmic radiation. This review analyses data on the influence of the GMF on different aspects of life and it also presents current knowledge in the area. In conclusion, the GMF has a positive impact on living organisms, whereas a diminishing or disappearing GMF negatively affects living organisms. The influence of the GMF may also be an important factor determining both survival of terrestrial organisms outside Earth and the emergence of life on other planets.