1
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Ghiaci P, Jouhten P, Martyushenko N, Roca-Mesa H, Vázquez J, Konstantinidis D, Stenberg S, Andrejev S, Grkovska K, Mas A, Beltran G, Almaas E, Patil KR, Warringer J. Highly parallelized laboratory evolution of wine yeasts for enhanced metabolic phenotypes. Mol Syst Biol 2024; 20:1109-1133. [PMID: 39174863 PMCID: PMC11450223 DOI: 10.1038/s44320-024-00059-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 07/17/2024] [Accepted: 07/30/2024] [Indexed: 08/24/2024] Open
Abstract
Adaptive Laboratory Evolution (ALE) of microorganisms can improve the efficiency of sustainable industrial processes important to the global economy. However, stochasticity and genetic background effects often lead to suboptimal outcomes during laboratory evolution. Here we report an ALE platform to circumvent these shortcomings through parallelized clonal evolution at an unprecedented scale. Using this platform, we evolved 104 yeast populations in parallel from many strains for eight desired wine fermentation-related traits. Expansions of both ALE replicates and lineage numbers broadened the evolutionary search spectrum leading to improved wine yeasts unencumbered by unwanted side effects. At the genomic level, evolutionary gains in metabolic characteristics often coincided with distinct chromosome amplifications and the emergence of side-effect syndromes that were characteristic of each selection niche. Several high-performing ALE strains exhibited desired wine fermentation kinetics when tested in larger liquid cultures, supporting their suitability for application. More broadly, our high-throughput ALE platform opens opportunities for rapid optimization of microbes which otherwise could take many years to accomplish.
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Affiliation(s)
- Payam Ghiaci
- Department of Chemistry and Molecular Biology, University of Gothenburg, PO Box 462, Gothenburg, 40530, Sweden
- Department of Biorefinery and Energy, High-throughput Centre, Research Institutes of Sweden, Örnsköldsvik, 89250, Sweden
- European Molecular Biology Laboratory, Heidelberg, 69117, Germany
| | - Paula Jouhten
- European Molecular Biology Laboratory, Heidelberg, 69117, Germany
- VTT Technical Research Centre of Finland Ltd, Espoo, 02044 VTT, Finland
- Aalto University, Department of Bioproducts and Biosystems, Espoo, 02150, Finland
| | - Nikolay Martyushenko
- Department of Biotechnology and Food Science, NTNU - Norwegian University of Science and Technology, Trondheim, Norway
| | - Helena Roca-Mesa
- Universitat Rovira i Virgili, Dept. Bioquímica i Biotecnologia, Facultat d'Enologia, Tarragona, 43007, Spain
| | - Jennifer Vázquez
- Universitat Rovira i Virgili, Dept. Bioquímica i Biotecnologia, Facultat d'Enologia, Tarragona, 43007, Spain
- Centro Tecnológico del Vino-VITEC, Carretera de Porrera Km. 1, Falset, 43730, Spain
| | | | - Simon Stenberg
- Department of Chemistry and Molecular Biology, University of Gothenburg, PO Box 462, Gothenburg, 40530, Sweden
| | - Sergej Andrejev
- European Molecular Biology Laboratory, Heidelberg, 69117, Germany
| | | | - Albert Mas
- Universitat Rovira i Virgili, Dept. Bioquímica i Biotecnologia, Facultat d'Enologia, Tarragona, 43007, Spain
| | - Gemma Beltran
- Universitat Rovira i Virgili, Dept. Bioquímica i Biotecnologia, Facultat d'Enologia, Tarragona, 43007, Spain
| | - Eivind Almaas
- Department of Biotechnology and Food Science, NTNU - Norwegian University of Science and Technology, Trondheim, Norway.
| | - Kiran R Patil
- European Molecular Biology Laboratory, Heidelberg, 69117, Germany.
- Medical Research Council (MRC) Toxicology Unit, University of Cambridge, Cambridge, CB2 1QR, UK.
| | - Jonas Warringer
- Department of Chemistry and Molecular Biology, University of Gothenburg, PO Box 462, Gothenburg, 40530, Sweden.
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2
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McGrath KM, Russell SJ, Fer E, Garmendia E, Hosgel A, Baltrus DA, Kaçar B. Fitness benefits of a synonymous substitution in an ancient EF-Tu gene depend on the genetic background. J Bacteriol 2024; 206:e0032923. [PMID: 38289064 PMCID: PMC10882980 DOI: 10.1128/jb.00329-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 01/05/2024] [Indexed: 02/13/2024] Open
Abstract
Synonymous mutations are changes to DNA sequence, which occur within translated genes but which do not affect the protein sequence. Although often referred to as silent mutations, evidence suggests that synonymous mutations can affect gene expression, mRNA stability, and even translation efficiency. A collection of both experimental and bioinformatic data has shown that synonymous mutations can impact cell phenotype, yet less is known about the molecular mechanisms and potential of beneficial or adaptive effects of such changes within evolved populations. Here, we report a beneficial synonymous mutation acquired via experimental evolution in an essential gene variant encoding the translation elongation factor protein EF-Tu. We demonstrate that this particular synonymous mutation increases EF-Tu mRNA and protein levels as well as global polysome abundance on RNA transcripts. Although presence of the synonymous mutation is clearly causative of such changes, we also demonstrate that fitness benefits are highly contingent on other potentiating mutations present within the genetic background in which the mutation arose. Our results underscore the importance of beneficial synonymous mutations, especially those that affect levels of proteins that are key for cellular processes.IMPORTANCEThis study explores the degree to which synonymous mutations in essential genes can influence adaptation in bacteria. An experimental system whereby an Escherichia coli strain harboring an engineered translation protein elongation factor-Tu (EF-Tu) was subjected to laboratory evolution. We find that a synonymous mutation acquired on the gene encoding for EF-Tu is conditionally beneficial for bacterial fitness. Our findings provide insight into the importance of the genetic background when a synonymous substitution is favored by natural selection and how such changes have the potential to impact evolution when critical cellular processes are involved.
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Affiliation(s)
- Kaitlyn M. McGrath
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Steven J. Russell
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Evrim Fer
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbial Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eva Garmendia
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Ali Hosgel
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - David A. Baltrus
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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3
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Cuevas-Zuviría B, Fer E, Adam ZR, Kaçar B. The modular biochemical reaction network structure of cellular translation. NPJ Syst Biol Appl 2023; 9:52. [PMID: 37884541 PMCID: PMC10603163 DOI: 10.1038/s41540-023-00315-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023] Open
Abstract
Translation is an essential attribute of all living cells. At the heart of cellular operation, it is a chemical information decoding process that begins with an input string of nucleotides and ends with the synthesis of a specific output string of peptides. The translation process is interconnected with gene expression, physiological regulation, transcription, and responses to signaling molecules, among other cellular functions. Foundational efforts have uncovered a wealth of knowledge about the mechanistic functions of the components of translation and their many interactions between them, but the broader biochemical connections between translation, metabolism and polymer biosynthesis that enable translation to occur have not been comprehensively mapped. Here we present a multilayer graph of biochemical reactions describing the translation, polymer biosynthesis and metabolism networks of an Escherichia coli cell. Intriguingly, the compounds that compose these three layers are distinctly aggregated into three modes regardless of their layer categorization. Multimodal mass distributions are well-known in ecosystems, but this is the first such distribution reported at the biochemical level. The degree distributions of the translation and metabolic networks are each likely to be heavy-tailed, but the polymer biosynthesis network is not. A multimodal mass-degree distribution indicates that the translation and metabolism networks are each distinct, adaptive biochemical modules, and that the gaps between the modes reflect evolved responses to the functional use of metabolite, polypeptide and polynucleotide compounds. The chemical reaction network of cellular translation opens new avenues for exploring complex adaptive phenomena such as percolation and phase changes in biochemical contexts.
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Affiliation(s)
- Bruno Cuevas-Zuviría
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Madrid, Spain
| | - Evrim Fer
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Zachary R Adam
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Department of Geosciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
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4
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McGrath KM, Russell SJ, Fer E, Garmendia E, Hosgel A, Baltrus DA, Kaçar B. A beneficial synonymous substitution in EF-Tu is contingent on genetic background. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.06.555949. [PMID: 37886545 PMCID: PMC10602032 DOI: 10.1101/2023.09.06.555949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Synonymous mutations are changes to DNA sequence that occur within translated genes but which do not affect the protein sequence. Although often referred to as silent mutations, evidence suggests that synonymous mutations can affect gene expression, mRNA stability, and even translation efficiency. A collection of both experimental and bioinformatic data has shown that synonymous mutations can impact cell phenotype, yet less is known about the molecular mechanisms and potential of beneficial or adaptive effects of such changes within evolved populations. Here, we report a beneficial synonymous mutation acquired via experimental evolution in an essential gene variant encoding the translation Elongation Factor protein EF-Tu. We demonstrate that this particular synonymous mutation increases EF-Tu mRNA and protein levels, as well as the polysome abundance on global transcripts. Although presence of the synonymous mutation is clearly causative of such changes, we also demonstrate that fitness benefits are highly contingent on other potentiating mutations present within the genetic background in which the mutation arose. Our results underscore the importance of beneficial synonymous mutations, especially those that affect levels of proteins that are key for cellular processes.
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Affiliation(s)
- Kaitlyn M. McGrath
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA
- School of Plant Sciences, University of Arizona, Tucson, AZ, USA
| | - Steven J. Russell
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Evrim Fer
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Microbial Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Eva Garmendia
- Department of Medical Biochemistry and Microbiology, Uppsala University, Sweden
| | - Ali Hosgel
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - David A. Baltrus
- School of Plant Sciences, University of Arizona, Tucson, AZ, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
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5
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Draghi JA, Ogbunugafor CB. Exploring the expanse between theoretical questions and experimental approaches in the modern study of evolvability. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:8-17. [PMID: 35451559 PMCID: PMC10083935 DOI: 10.1002/jez.b.23134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/04/2022] [Accepted: 03/11/2022] [Indexed: 12/16/2022]
Abstract
Despite several decades of computational and experimental work across many systems, evolvability remains on the periphery with regards to its status as a widely accepted and regularly applied theoretical concept. Here we propose that its marginal status is partly a result of large gaps between the diverse but disconnected theoretical treatments of evolvability and the relatively narrower range of studies that have tested it empirically. To make this case, we draw on a range of examples-from experimental evolution in microbes, to molecular evolution in proteins-where attempts have been made to mend this disconnect. We highlight some examples of progress that has been made and point to areas where synthesis and translation of existing theory can lead to further progress in the still-new field of empirical measurements of evolvability.
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Affiliation(s)
- Jeremy A Draghi
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - C Brandon Ogbunugafor
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, Connecticut, USA
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6
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Venkataram S, Kuo HY, Hom EFY, Kryazhimskiy S. Mutualism-enhancing mutations dominate early adaptation in a two-species microbial community. Nat Ecol Evol 2023; 7:143-154. [PMID: 36593292 DOI: 10.1038/s41559-022-01923-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/03/2022] [Indexed: 01/03/2023]
Abstract
Species interactions drive evolution while evolution shapes these interactions. The resulting eco-evolutionary dynamics and their repeatability depend on how adaptive mutations available to community members affect fitness and ecologically relevant traits. However, the diversity of adaptive mutations is not well characterized, and we do not know how this diversity is affected by the ecological milieu. Here we use barcode lineage tracking to address this question in a community of yeast Saccharomyces cerevisiae and alga Chlamydomonas reinhardtii that have a net commensal relationship that results from a balance between competitive and mutualistic interactions. We find that yeast has access to many adaptive mutations with diverse ecological consequences, in particular those that increase and reduce the yields of both species. The presence of the alga does not change which mutations are adaptive in yeast (that is, there is no fitness trade-off for yeast between growing alone or with alga), but rather shifts selection to favour yeast mutants that increase the yields of both species and make the mutualism stronger. Thus, in the presence of the alga, adaptative mutations contending for fixation in yeast are more likely to enhance the mutualism, even though cooperativity is not directly favoured by natural selection in our system. Our results demonstrate that ecological interactions not only alter the trajectory of evolution but also dictate its repeatability; in particular, weak mutualisms can repeatably evolve to become stronger.
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Affiliation(s)
- Sandeep Venkataram
- Department of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, CA, USA
| | - Huan-Yu Kuo
- Department of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, CA, USA.,Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - Erik F Y Hom
- Department of Biology and Center for Biodiversity and Conservation Research, University of Mississippi, University, MS, USA
| | - Sergey Kryazhimskiy
- Department of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, CA, USA.
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7
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Fer E, McGrath KM, Guy L, Hockenberry AJ, Kaçar B. Early divergence of translation initiation and elongation factors. Protein Sci 2022; 31:e4393. [PMID: 36250475 PMCID: PMC9601768 DOI: 10.1002/pro.4393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/05/2022] [Accepted: 07/11/2022] [Indexed: 11/18/2022]
Abstract
Protein translation is a foundational attribute of all living cells. The translation function carried out by the ribosome critically depends on an assortment of protein interaction partners, collectively referred to as the translation machinery. Various studies suggest that the diversification of the translation machinery occurred prior to the last universal common ancestor, yet it is unclear whether the predecessors of the extant translation machinery factors were functionally distinct from their modern counterparts. Here we reconstructed the shared ancestral trajectory and subsequent evolution of essential translation factor GTPases, elongation factor EF-Tu (aEF-1A/eEF-1A), and initiation factor IF2 (aIF5B/eIF5B). Based upon their similar functions and structural homologies, it has been proposed that EF-Tu and IF2 emerged from an ancient common ancestor. We generated the phylogenetic tree of IF2 and EF-Tu proteins and reconstructed ancestral sequences corresponding to the deepest nodes in their shared evolutionary history, including the last common IF2 and EF-Tu ancestor. By identifying the residue and domain substitutions, as well as structural changes along the phylogenetic history, we developed an evolutionary scenario for the origins, divergence and functional refinement of EF-Tu and IF2 proteins. Our analyses suggest that the common ancestor of IF2 and EF-Tu was an IF2-like GTPase protein. Given the central importance of the translation machinery to all cellular life, its earliest evolutionary constraints and trajectories are key to characterizing the universal constraints and capabilities of cellular evolution.
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Affiliation(s)
- Evrim Fer
- Department of BacteriologyUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
- Microbiology Doctoral Training ProgramUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
- NASA Center for Early Life and EvolutionUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
| | - Kaitlyn M. McGrath
- Department of BacteriologyUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
- NASA Center for Early Life and EvolutionUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
- Department of Molecular and Cellular BiologyUniversity of ArizonaTucsonArizonaUSA
| | - Lionel Guy
- Department of Medical Biochemistry and Microbiology, Science for Life LaboratoryUppsala UniversityUppsalaSweden
| | - Adam J. Hockenberry
- Department of Integrative BiologyThe University of Texas at AustinAustinTexasUSA
| | - Betül Kaçar
- Department of BacteriologyUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
- NASA Center for Early Life and EvolutionUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
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8
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Pennings PS, Ogbunugafor CB, Hershberg R. Reversion is most likely under high mutation supply when compensatory mutations do not fully restore fitness costs. G3 (BETHESDA, MD.) 2022; 12:jkac190. [PMID: 35920784 PMCID: PMC9434179 DOI: 10.1093/g3journal/jkac190] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 10/02/2021] [Indexed: 06/15/2023]
Abstract
The dynamics of adaptation, reversion, and compensation have been central topics in microbial evolution, and several studies have attempted to resolve the population genetics underlying how these dynamics occur. However, questions remain regarding how certain features-the evolution of mutators and whether compensatory mutations alleviate costs fully or partially-may influence the evolutionary dynamics of compensation and reversion. In this study, we attempt to explain findings from experimental evolution by utilizing computational and theoretical approaches toward a more refined understanding of how mutation rate and the fitness effects of compensatory mutations influence adaptive dynamics. We find that high mutation rates increase the probability of reversion toward the wild type when compensation is only partial. However, the existence of even a single fully compensatory mutation is associated with a dramatically decreased probability of reversion to the wild type. These findings help to explain specific results from experimental evolution, where compensation was observed in nonmutator strains, but reversion (sometimes with compensation) was observed in mutator strains, indicating that real-world compensatory mutations are often unable to fully alleviate the costs associated with adaptation. Our findings emphasize the potential role of the supply and quality of mutations in crafting the dynamics of adaptation and reversal, with implications for theoretical population genetics and for biomedical contexts like the evolution of antibiotic resistance.
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Affiliation(s)
- Pleuni S Pennings
- Corresponding author: Department of Biology, San Francisco State University, San Francisco, CA 94132, USA.
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9
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Maddamsetti R, Grant NA. Discovery of positive and purifying selection in metagenomic time series of hypermutator microbial populations. PLoS Genet 2022; 18:e1010324. [PMID: 35981004 PMCID: PMC9426924 DOI: 10.1371/journal.pgen.1010324] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 08/30/2022] [Accepted: 07/04/2022] [Indexed: 11/18/2022] Open
Abstract
A general method to infer both positive and purifying selection during the real-time evolution of hypermutator pathogens would be broadly useful. To this end, we introduce a Simple Test to Infer Mode of Selection (STIMS) from metagenomic time series of evolving microbial populations. We test STIMS on metagenomic data generated by simulations of bacterial evolution, and on metagenomic data spanning 62,750 generations of Lenski's long-term evolution experiment with Escherichia coli (LTEE). This benchmarking shows that STIMS detects positive selection in both nonmutator and hypermutator populations, and purifying selection in hypermutator populations. Using STIMS, we find strong evidence of ongoing positive selection on key regulators of the E. coli gene regulatory network, even in some hypermutator populations. STIMS also detects positive selection on regulatory genes in hypermutator populations of Pseudomonas aeruginosa that adapted to subinhibitory concentrations of colistin-an antibiotic of last resort-for just twenty-six days of laboratory evolution. Our results show that the fine-tuning of gene regulatory networks is a general mechanism for rapid and ongoing adaptation. The simplicity of STIMS, together with its intuitive visual interpretation, make it a useful test for positive and purifying selection in metagenomic data sets that track microbial evolution in real-time.
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Affiliation(s)
- Rohan Maddamsetti
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Nkrumah A. Grant
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan, United States of America
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
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10
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Wong ML, Bartlett S. Asymptotic burnout and homeostatic awakening: a possible solution to the Fermi paradox? J R Soc Interface 2022; 19:20220029. [PMID: 35506212 PMCID: PMC9065981 DOI: 10.1098/rsif.2022.0029] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Previous studies show that city metrics having to do with growth, productivity and overall energy consumption scale superlinearly, attributing this to the social nature of cities. Superlinear scaling results in crises called ‘singularities’, where population and energy demand tend to infinity in a finite amount of time, which must be avoided by ever more frequent ‘resets’ or innovations that postpone the system's collapse. Here, we place the emergence of cities and planetary civilizations in the context of major evolutionary transitions. With this perspective, we hypothesize that once a planetary civilization transitions into a state that can be described as one virtually connected global city, it will face an ‘asymptotic burnout’, an ultimate crisis where the singularity-interval time scale becomes smaller than the time scale of innovation. If a civilization develops the capability to understand its own trajectory, it will have a window of time to affect a fundamental change to prioritize long-term homeostasis and well-being over unyielding growth—a consciously induced trajectory change or ‘homeostatic awakening’. We propose a new resolution to the Fermi paradox: civilizations either collapse from burnout or redirect themselves to prioritizing homeostasis, a state where cosmic expansion is no longer a goal, making them difficult to detect remotely.
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Affiliation(s)
- Michael L Wong
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA
| | - Stuart Bartlett
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
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11
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Ogbunugafor CB. The mutation effect reaction norm (mu-rn) highlights environmentally dependent mutation effects and epistatic interactions. Evolution 2022; 76:37-48. [PMID: 34989399 DOI: 10.1111/evo.14428] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 12/23/2021] [Indexed: 11/27/2022]
Abstract
Since the modern synthesis, the fitness effects of mutations and epistasis have been central yet provocative concepts in evolutionary and population genetics. Studies of how the interactions between parcels of genetic information can change as a function of environmental context have added a layer of complexity to these discussions. Here I introduce the "mutation effect reaction norm" (Mu-RN), a new instrument through which one can analyze the phenotypic consequences of mutations and interactions across environmental contexts. It embodies the fusion of measurements of genetic interactions with the reaction norm, a classic depiction of the performance of genotypes across environments. I demonstrate the utility of the Mu-RN through the signature of a "compensatory ratchet" mutation that undermines reverse evolution of antimicrobial resistance. More broadly, I argue that the mutation effect reaction norm may help us resolve the dynamism and unpredictability of evolution, with implications for theoretical biology, genetic modification technology, and public health. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- C Brandon Ogbunugafor
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA
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12
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Garcia AK, Fer E, Sephus C, Kacar B. An Integrated Method to Reconstruct Ancient Proteins. Methods Mol Biol 2022; 2569:267-281. [PMID: 36083453 DOI: 10.1007/978-1-0716-2691-7_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Proteins have played a fundamental role throughout life's history on Earth. Despite their biological importance, ancient origin, early function, and evolution of proteins are seldom able to be directly studied because few of these attributes are preserved across geologic timescales. Ancestral sequence reconstruction (ASR) provides a method to infer ancestral amino acid sequences and determine the evolutionary predecessors of modern-day proteins using phylogenetic tools. Laboratory application of ASR allows ancient sequences to be deduced from genetic information available in extant organisms and then experimentally resurrected to elucidate ancestral characteristics. In this article, we provide a generalized, stepwise protocol that considers the major elements of a well-designed ASR study and details potential sources of reconstruction bias that can reduce the relevance of historical inferences. We underscore key stages in our approach so that it may be broadly utilized to reconstruct the evolutionary histories of proteins.
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Affiliation(s)
- Amanda K Garcia
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Evrim Fer
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Cathryn Sephus
- Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA, USA
| | - Betul Kacar
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
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13
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Ardell SM, Kryazhimskiy S. The population genetics of collateral resistance and sensitivity. eLife 2021; 10:73250. [PMID: 34889185 PMCID: PMC8765753 DOI: 10.7554/elife.73250] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 12/06/2021] [Indexed: 12/05/2022] Open
Abstract
Resistance mutations against one drug can elicit collateral sensitivity against other drugs. Multi-drug treatments exploiting such trade-offs can help slow down the evolution of resistance. However, if mutations with diverse collateral effects are available, a treated population may evolve either collateral sensitivity or collateral resistance. How to design treatments robust to such uncertainty is unclear. We show that many resistance mutations in Escherichia coli against various antibiotics indeed have diverse collateral effects. We propose to characterize such diversity with a joint distribution of fitness effects (JDFE) and develop a theory for describing and predicting collateral evolution based on simple statistics of the JDFE. We show how to robustly rank drug pairs to minimize the risk of collateral resistance and how to estimate JDFEs. In addition to practical applications, these results have implications for our understanding of evolution in variable environments. Drugs known as antibiotics are the main treatment for most serious infections caused by bacteria. However, many bacteria are acquiring genetic mutations that make them resistant to the effects of one or more types of antibiotics, making them harder to eliminate. One way to tackle drug-resistant bacteria is to develop new types of antibiotics; however, in recent years, the rate at which new antibiotics have become available has been dwindling. Using two or more existing drugs, one after another, can also be an effective way to eliminate resistant bacteria. The success of any such ‘multi-drug’ treatment lies in being able to predict whether mutations that make the bacteria resistant to one drug simultaneously make it sensitive to another, a phenomenon known as collateral sensitivity. Different resistance mutations may have different collateral effects: some may increase the bacteria’s sensitivity to the second drug, while others might make the bacteria more resistant. However, it is currently unclear how to design robust multi-drug treatments that take this diversity of collateral effects into account. Here, Ardell and Kryazhimskiy used a concept called JDFE (short for the joint distribution of fitness effects) to describe the diversity of collateral effects in a population of bacteria exposed to a single drug. This information was then used to mathematically model how collateral effects evolved in the population over time. Ardell and Kryazhimskiy showed that this approach can predict how likely a population is to become collaterally sensitive or collaterally resistant to a second antibiotic. Drug pairs can then be ranked according to the risk of collateral resistance emerging, so long as information on the variety of resistance mutations available to the bacteria are included in the model. Each year, more than 700,000 people die from infections caused by bacteria that are resistant to one or more antibiotics. The findings of Ardell and Kryazhimskiy may eventually help clinicians design multi-drug treatments that effectively eliminate bacterial infections and help to prevent more bacteria from evolving resistance to antibiotics. However, to achieve this goal, more research is needed to fully understand the range collateral effects caused by resistance mutations.
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Affiliation(s)
- Sarah M Ardell
- Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Sergey Kryazhimskiy
- Division of Biological Sciences, University of California, San Diego, La Jolla, United States
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14
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Penev PI, Fakhretaha-Aval S, Patel VJ, Cannone JJ, Gutell RR, Petrov AS, Williams LD, Glass JB. Supersized Ribosomal RNA Expansion Segments in Asgard Archaea. Genome Biol Evol 2021; 12:1694-1710. [PMID: 32785681 PMCID: PMC7594248 DOI: 10.1093/gbe/evaa170] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2020] [Indexed: 12/11/2022] Open
Abstract
The ribosome’s common core, comprised of ribosomal RNA (rRNA) and universal ribosomal proteins, connects all life back to a common ancestor and serves as a window to relationships among organisms. The rRNA of the common core is similar to rRNA of extant bacteria. In eukaryotes, the rRNA of the common core is decorated by expansion segments (ESs) that vastly increase its size. Supersized ESs have not been observed previously in Archaea, and the origin of eukaryotic ESs remains enigmatic. We discovered that the large ribosomal subunit (LSU) rRNA of two Asgard phyla, Lokiarchaeota and Heimdallarchaeota, considered to be the closest modern archaeal cell lineages to Eukarya, bridge the gap in size between prokaryotic and eukaryotic LSU rRNAs. The elongated LSU rRNAs in Lokiarchaeota and Heimdallarchaeota stem from two supersized ESs, called ES9 and ES39. We applied chemical footprinting experiments to study the structure of Lokiarchaeota ES39. Furthermore, we used covariation and sequence analysis to study the evolution of Asgard ES39s and ES9s. By defining the common eukaryotic ES39 signature fold, we found that Asgard ES39s have more and longer helices than eukaryotic ES39s. Although Asgard ES39s have sequences and structures distinct from eukaryotic ES39s, we found overall conservation of a three-way junction across the Asgard species that matches eukaryotic ES39 topology, a result consistent with the accretion model of ribosomal evolution.
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Affiliation(s)
- Petar I Penev
- Georgia Institute of Technology, NASA Center for the Origin of Life, Atlanta, Georgia.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia
| | - Sara Fakhretaha-Aval
- Georgia Institute of Technology, NASA Center for the Origin of Life, Atlanta, Georgia.,School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia
| | - Vaishnavi J Patel
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas
| | - Jamie J Cannone
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas
| | - Robin R Gutell
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas
| | - Anton S Petrov
- Georgia Institute of Technology, NASA Center for the Origin of Life, Atlanta, Georgia.,School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia
| | - Loren Dean Williams
- Georgia Institute of Technology, NASA Center for the Origin of Life, Atlanta, Georgia.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia.,School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia
| | - Jennifer B Glass
- Georgia Institute of Technology, NASA Center for the Origin of Life, Atlanta, Georgia.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia.,School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia
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15
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Changes in the distribution of fitness effects and adaptive mutational spectra following a single first step towards adaptation. Nat Commun 2021; 12:5193. [PMID: 34465770 PMCID: PMC8408183 DOI: 10.1038/s41467-021-25440-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/11/2021] [Indexed: 01/17/2023] Open
Abstract
Historical contingency and diminishing returns epistasis have been typically studied for relatively divergent genotypes and/or over long evolutionary timescales. Here, we use Saccharomyces cerevisiae to study the extent of diminishing returns and the changes in the adaptive mutational spectra following a single first adaptive mutational step. We further evolve three clones that arose under identical conditions from a common ancestor. We follow their evolutionary dynamics by lineage tracking and determine adaptive outcomes using fitness assays and whole genome sequencing. We find that diminishing returns manifests as smaller fitness gains during the 2nd step of adaptation compared to the 1st step, mainly due to a compressed distribution of fitness effects. We also find that the beneficial mutational spectra for the 2nd adaptive step are contingent on the 1st step, as we see both shared and diverging adaptive strategies. Finally, we find that adaptive loss-of-function mutations, such as nonsense and frameshift mutations, are less common in the second step of adaptation than in the first step. Analyses of both natural and experimental evolution suggest that adaptation depends on the evolutionary past and adaptive potential decreases over time. Here, by tracking yeast adaptation with DNA barcoding, the authors show that such evolutionary phenomena can be observed even after a single adaptive step.
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16
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Parys K, Colaianni NR, Lee HS, Hohmann U, Edelbacher N, Trgovcevic A, Blahovska Z, Lee D, Mechtler A, Muhari-Portik Z, Madalinski M, Schandry N, Rodríguez-Arévalo I, Becker C, Sonnleitner E, Korte A, Bläsi U, Geldner N, Hothorn M, Jones CD, Dangl JL, Belkhadir Y. Signatures of antagonistic pleiotropy in a bacterial flagellin epitope. Cell Host Microbe 2021; 29:620-634.e9. [DOI: 10.1016/j.chom.2021.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/04/2021] [Accepted: 02/11/2021] [Indexed: 12/20/2022]
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17
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Goldman AD, Kacar B. Cofactors are Remnants of Life's Origin and Early Evolution. J Mol Evol 2021; 89:127-133. [PMID: 33547911 PMCID: PMC7982383 DOI: 10.1007/s00239-020-09988-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 12/21/2020] [Indexed: 12/22/2022]
Abstract
The RNA World is one of the most widely accepted hypotheses explaining the origin of the genetic system used by all organisms today. It proposes that the tripartite system of DNA, RNA, and proteins was preceded by one consisting solely of RNA, which both stored genetic information and performed the molecular functions encoded by that genetic information. Current research into a potential RNA World revolves around the catalytic properties of RNA-based enzymes, or ribozymes. Well before the discovery of ribozymes, Harold White proposed that evidence for a precursor RNA world could be found within modern proteins in the form of coenzymes, the majority of which contain nucleobases or nucleoside moieties, such as Coenzyme A and S-adenosyl methionine, or are themselves nucleotides, such as ATP and NADH (a dinucleotide). These coenzymes, White suggested, had been the catalytic active sites of ancient ribozymes, which transitioned to their current forms after the surrounding ribozyme scaffolds had been replaced by protein apoenzymes during the evolution of translation. Since its proposal four decades ago, this groundbreaking hypothesis has garnered support from several different research disciplines and motivated similar hypotheses about other classes of cofactors, most notably iron-sulfur cluster cofactors as remnants of the geochemical setting of the origin of life. Evidence from prebiotic geochemistry, ribozyme biochemistry, and evolutionary biology, increasingly supports these hypotheses. Certain coenzymes and cofactors may bridge modern biology with the past and can thus provide insights into the elusive and poorly-recorded period of the origin and early evolution of life.
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Affiliation(s)
- Aaron D Goldman
- Department of Biology, Oberlin College and Conservatory, Oberlin, OH, 44074, USA. .,Blue Marble Space Institute of Science, Seattle, WA, 98154, USA.
| | - Betul Kacar
- Blue Marble Space Institute of Science, Seattle, WA, 98154, USA. .,Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, 85721, USA. .,Lunar and Planetary Laboratory and Department of Astronomy, University of Arizona, Tucson, AZ, 85721, USA. .,Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo, 152-8550, Japan.
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18
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Kinsler G, Geiler-Samerotte K, Petrov DA. Fitness variation across subtle environmental perturbations reveals local modularity and global pleiotropy of adaptation. eLife 2020; 9:e61271. [PMID: 33263280 PMCID: PMC7880691 DOI: 10.7554/elife.61271] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 12/02/2020] [Indexed: 02/07/2023] Open
Abstract
Building a genotype-phenotype-fitness map of adaptation is a central goal in evolutionary biology. It is difficult even when adaptive mutations are known because it is hard to enumerate which phenotypes make these mutations adaptive. We address this problem by first quantifying how the fitness of hundreds of adaptive yeast mutants responds to subtle environmental shifts. We then model the number of phenotypes these mutations collectively influence by decomposing these patterns of fitness variation. We find that a small number of inferred phenotypes can predict fitness of the adaptive mutations near their original glucose-limited evolution condition. Importantly, inferred phenotypes that matter little to fitness at or near the evolution condition can matter strongly in distant environments. This suggests that adaptive mutations are locally modular - affecting a small number of phenotypes that matter to fitness in the environment where they evolved - yet globally pleiotropic - affecting additional phenotypes that may reduce or improve fitness in new environments.
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Affiliation(s)
- Grant Kinsler
- Department of Biology, Stanford UniversityStanfordUnited States
| | - Kerry Geiler-Samerotte
- Department of Biology, Stanford UniversityStanfordUnited States
- Center for Mechanisms of Evolution, School of Life Sciences, Arizona State UniversityTempeUnited States
| | - Dmitri A Petrov
- Department of Biology, Stanford UniversityStanfordUnited States
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19
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Gomez K, Bertram J, Masel J. Mutation bias can shape adaptation in large asexual populations experiencing clonal interference. Proc Biol Sci 2020; 287:20201503. [PMID: 33081612 DOI: 10.1098/rspb.2020.1503] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The extended evolutionary synthesis invokes a role for development in shaping adaptive evolution, which in population genetics terms corresponds to mutation-biased adaptation. Critics have claimed that clonal interference makes mutation-biased adaptation rare. We consider the behaviour of two simultaneously adapting traits, one with larger mutation rate U, the other with larger selection coefficient s, using asexual travelling wave models. We find that adaptation is dominated by whichever trait has the faster rate of adaptation v in isolation, with the other trait subject to evolutionary stalling. Reviewing empirical claims for mutation-biased adaptation, we find that not all occur in the 'origin-fixation' regime of population genetics where v is only twice as sensitive to s as to U. In some cases, differences in U are at least ten to twelve times larger than differences in s, as needed to cause mutation-biased adaptation even in the 'multiple mutations' regime. Surprisingly, when U > s in the 'diffusive-mutation' regime, the required sensitivity ratio is also only two, despite pervasive clonal interference. Given two traits with identical v, the benefit of having higher s is surprisingly small, occurring largely when one trait is at the boundary between the origin-fixation and multiple mutations regimes.
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Affiliation(s)
- Kevin Gomez
- Graduate Interdisciplinary Program in Applied Mathematics, University of Arizona, Tucson, AZ, USA
| | - Jason Bertram
- Environmental Resilience Institute, Indiana University, Bloomington, IN, USA.,Department of Biology, Indiana University, Bloomington, IN, USA
| | - Joanna Masel
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
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