The chaos law is a principal driver of natural selection: A proposition on the evolution of recently emerged coronaviruses

PLOS ONE RESEARCH ARTICLE The chaos law is a principal driver of natural selection: A proposition on the evolution of recently emerged coronaviruses Pier Francesco Roggero1☯, Arianna Calistri1☯, Giorgio Palù1,2* 1 Department of Molecular Medicine, University of Padua, via A. Gabelli, Padua, Italy, 2 Italian Medicines Agency, Via del Tritone, Rome, Italy a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Roggero PF, Calistri A, Palù G (2023) The chaos law is a principal driver of natural selection: A proposition on the evolution of recently emerged coronaviruses. PLoS ONE 18(8): e0290453. https://doi.org/10.1371/journal.pone.0290453 Editor: Vittorio Sambri, University of Bologna / Romagna Local Health Authority, ITALY Received: April 20, 2023 Accepted: August 8, 2023 Published: August 24, 2023 Copyright: © 2023 Roggero et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: Data can be accessed at the following links SARS-CoV-2: https://www. worldometers.info/coronavirus/#main_table, last accessed on 06/07/2023 SARS-CoV-1: https:// www.who.int/health-topics/severe-acuterespiratory-syndrome#tab=tab_1, last accessed on 09/02/2023 MERS-CoV: https://www.emro.who. int/health-topics/mers-cov/mers-outbreaks.html, last accessed on 09/02/2023 Ebola virus: https:// apps.who.int/gho/data/view.ebola-sitrep.ebolasummary-20150331?lang=en (World Health Organization Report), last accessed on 09/02/2023. ☯ These authors contributed equally to this work. * Abstract Here we propose that viruses emerging in the human population undergo an evolution that is conditioned by the rules of chaos. Our data support the notion that the initial growth rate “r” affects the chances of the virus to establish a long-lasting relationship with the new host. Indeed, an emerging virus is able to spread and adapt only when it displays an initial r falling in a range frankly associated with chaotic growth. Introduction Members of the same species differ from each other by genetic and, therefore, phenotypic characteristics, i.e. morphological and functional features, the result of the interaction of the genotype with the environment. Darwin’s natural selection is a key evolutionary mechanism according to which, within the genetic diversity of populations, there is a progressive and cumulative increase of individuals optimized for their living environment [1]. This variability derives from random genetic mutations, in the sense that they occur by chance, during the generations [2]. Those mutations that confer advantages, e.g. in terms of survival and reproduction, are maintained and spread in the population. Genes heralding an adaptive advantage can be vertically transmitted to the progeny with a progressive affirmation of good genes at the expense of the less useful, non-useful or harmful ones. Interestingly, it has been proposed that evolution tends towards states of greater disorder defined as entropy [3, 4]. The entropy of systems increases not because of an ominous tendency of the universe toward disorder, but due to a tendency toward most probable states, where most probable means those states corresponding to a greater number of molecular, atomic and subatomic variations. Chaos is therefore much more likely than the order. Based on these considerations, the chaos inherent in the environment would represent the first motor of evolution leading to the emergence of mutations that will be selected according to the criterion of advantageousness. The species will progressively adapt to the environment until an equilibrium is reached, which is perturbed when a novel change arises, once again due to the intrinsic chaos of the environment. Chaos itself would be driven by an attractor entity presiding over evolution, thus not representing pure randomness [5, 6]. PLOS ONE | https://doi.org/10.1371/journal.pone.0290453 August 24, 2023 1/9 PLOS ONE Funding: The authors received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist. Chaos and evolution of recently emerged coronaviruses To support the proposition that chaos is the master of evolution, we adopted viruses as a model since they are the simplest biological entities most prone to mutate. In particular, we considered the recently emerged coronaviruses, i.e. the pandemic Severe Acute Respiratory Syndrome CoronaVirus-2 (SARS-CoV-2), the etiological agent of COVID-19 [7, 8], as well as the non-pandemic SARS-CoV-1 and Middle East Respiratory Syndrome (MERS)-CoV [9]. These viruses are particularly interesting to investigate and compare in terms of mutation, evolution and adaptation, since they possess the largest genome among riboviruses and share a common zoonotic origin. Moreover, all epidemiological parameters are available for these coronaviruses as they became human pathogens in recent years and were all classified as public health emergencies of international concern (PHEIC). An approach at the cellular level would not be feasible since it will be constrained by the cellular model utilized and inevitably fail to give a real picture of the whole phenomenon as it occurs in vivo. When these viruses replicate, random mutations occur that can be advantageous or unfavorable. If they are advantageous, increasing for example the ability of the virus to enter into target cells, or to evade the immune response, as the mutations closely located in the RBD region of the S protein of SARS-CoV-2 [10], the mutant virus will take over the wild type parental strain and this will eventually disappear. Mutations tend to converge in specific regions of the genome, as only favorable changes are maintained and transmitted to the progeny that guarantee viral survival. Indeed, due to their nature of obliged intracellular parasites viruses co-evolve with the host cells to adapt and persist as long as possible in their ecological niche. In conclusion, two conditions determine viral features: 1) the emergence of random mutations; 2) the time of co-evolution with the host. Mutations will be transmitted if they increase the probability of the virus to be maintained in the host population. Materials and methods Laboratory-confirmed cases of infections In this study the number of laboratory-confirmed cases of different viral infections registered over time were adopted to calculate a set of parameters. This number was retrieved by consulting publically accessible repositories, that are reported below along with the last accession date. SARS-CoV-2: https://www.worldometers.info/coronavirus/#main_table, last accessed on 06/07/2023 SARS-CoV-1: https://www.who.int/health-topics/severe-acute-respiratory-syndrome#tab= tab_1, last accessed on 09/02/2023 MERS-CoV: https://ww (...truncated)