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Hudson CM, Stalder D, Vorburger C. Clines of resistance to parasitoids: the multifarious effects of temperature on defensive symbioses in insects. CURRENT OPINION IN INSECT SCIENCE 2024; 64:101208. [PMID: 38821141 DOI: 10.1016/j.cois.2024.101208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/02/2024] [Accepted: 05/24/2024] [Indexed: 06/02/2024]
Abstract
Insects are frequently infected with heritable bacterial endosymbionts. Some of them confer resistance to parasitoids. Such defensive symbionts are sensitive to variation in temperature. Drawing predominantly from the literature on aphids and flies, we show that temperature can affect the reliability of maternal transmission and the strength of protection provided by defensive symbionts. Costs of infection with defensive symbionts can also be temperature-dependent and may even turn into benefits under extreme temperatures, for example, when defensive symbionts increase heat tolerance. Alone or in combination, these mechanisms can drive temperature-associated (latitudinal) clines of infection prevalence with defensive symbionts. This has important consequences for host-parasitoid coevolution, as the relative importance of host-encoded vs. symbiont-provided defenses will shift along such clines.
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Affiliation(s)
- Cameron M Hudson
- Aquatic Ecology, Eawag, Überlandstrasse 133, P.O. Box 611, 8600 Dübendorf, Switzerland
| | - Dominic Stalder
- Aquatic Ecology, Eawag, Überlandstrasse 133, P.O. Box 611, 8600 Dübendorf, Switzerland; Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland
| | - Christoph Vorburger
- Aquatic Ecology, Eawag, Überlandstrasse 133, P.O. Box 611, 8600 Dübendorf, Switzerland; Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland.
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2
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Patel V, Lynn-Bell N, Chevignon G, Kucuk RA, Higashi CHV, Carpenter M, Russell JA, Oliver KM. Mobile elements create strain-level variation in the services conferred by an aphid symbiont. Environ Microbiol 2023; 25:3333-3348. [PMID: 37864320 DOI: 10.1111/1462-2920.16520] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/27/2023] [Indexed: 10/22/2023]
Abstract
Heritable, facultative symbionts are common in arthropods, often functioning in host defence. Despite moderately reduced genomes, facultative symbionts retain evolutionary potential through mobile genetic elements (MGEs). MGEs form the primary basis of strain-level variation in genome content and architecture, and often correlate with variability in symbiont-mediated phenotypes. In pea aphids (Acyrthosiphon pisum), strain-level variation in the type of toxin-encoding bacteriophages (APSEs) carried by the bacterium Hamiltonella defensa correlates with strength of defence against parasitoids. However, co-inheritance creates difficulties for partitioning their relative contributions to aphid defence. Here we identified isolates of H. defensa that were nearly identical except for APSE type. When holding H. defensa genotype constant, protection levels corresponded to APSE virulence module type. Results further indicated that APSEs move repeatedly within some H. defensa clades providing a mechanism for rapid evolution in anti-parasitoid defences. Strain variation in H. defensa also correlates with the presence of a second symbiont Fukatsuia symbiotica. Predictions that nutritional interactions structured this coinfection were not supported by comparative genomics, but bacteriocin-containing plasmids unique to co-infecting strains may contribute to their common pairing. In conclusion, strain diversity, and joint capacities for horizontal transfer of MGEs and symbionts, are emergent players in the rapid evolution of arthropods.
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Affiliation(s)
- Vilas Patel
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Nicole Lynn-Bell
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Germain Chevignon
- Laboratoire de Génétique et Pathologie des Mollusques Marins, IFREMER, La Tremblade, France
| | - Roy A Kucuk
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | | | - Melissa Carpenter
- Department of Biodiversity, Earth, and Environmental Science, Drexel University, Philadelphia, Pennsylvania, USA
| | - Jacob A Russell
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Kerry M Oliver
- Department of Entomology, University of Georgia, Athens, Georgia, USA
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3
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Oliver KM. Flies co-opt bacterial toxins for use in defense against parasitoids. Proc Natl Acad Sci U S A 2023; 120:e2304493120. [PMID: 37126694 PMCID: PMC10175828 DOI: 10.1073/pnas.2304493120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023] Open
Affiliation(s)
- Kerry M. Oliver
- Department of Entomology, University of Georgia, Athens, GA30602
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4
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Verster KI, Cinege G, Lipinszki Z, Magyar LB, Kurucz É, Tarnopol RL, Ábrahám E, Darula Z, Karageorgi M, Tamsil JA, Akalu SM, Andó I, Whiteman NK. Evolution of insect innate immunity through domestication of bacterial toxins. Proc Natl Acad Sci U S A 2023; 120:e2218334120. [PMID: 37036995 PMCID: PMC10120054 DOI: 10.1073/pnas.2218334120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 03/01/2023] [Indexed: 04/12/2023] Open
Abstract
Toxin cargo genes are often horizontally transferred by phages between bacterial species and are known to play an important role in the evolution of bacterial pathogenesis. Here, we show how these same genes have been horizontally transferred from phage or bacteria to animals and have resulted in novel adaptations. We discovered that two widespread bacterial genes encoding toxins of animal cells, cytolethal distending toxin subunit B (cdtB) and apoptosis-inducing protein of 56 kDa (aip56), were captured by insect genomes through horizontal gene transfer from bacteria or phages. To study the function of these genes in insects, we focused on Drosophila ananassae as a model. In the D. ananassae subgroup species, cdtB and aip56 are present as singular (cdtB) or fused copies (cdtB::aip56) on the second chromosome. We found that cdtB and aip56 genes and encoded proteins were expressed by immune cells, some proteins were localized to the wasp embryo's serosa, and their expression increased following parasitoid wasp infection. Species of the ananassae subgroup are highly resistant to parasitoid wasps, and we observed that D. ananassae lines carrying null mutations in cdtB and aip56 toxin genes were more susceptible to parasitoids than the wild type. We conclude that toxin cargo genes were captured by these insects millions of years ago and integrated as novel modules into their innate immune system. These modules now represent components of a heretofore undescribed defense response and are important for resistance to parasitoid wasps. Phage or bacterially derived eukaryotic toxin genes serve as macromutations that can spur the instantaneous evolution of novelty in animals.
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Affiliation(s)
- Kirsten I. Verster
- Department of Integrative Biology, University of California, Berkeley, CA94720
| | - Gyöngyi Cinege
- Innate Immunity Group, Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, Szeged6726, Hungary
| | - Zoltán Lipinszki
- MTA SZBK Lendület Laboratory of Cell Cycle Regulation, Institute of Biochemistry, Biological Research Centre, Eötvös Loránd Research Network, Szeged6726, Hungary
| | - Lilla B. Magyar
- Innate Immunity Group, Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, Szeged6726, Hungary
- Doctoral School of Biology, University of Szeged, Szeged6720, Hungary
| | - Éva Kurucz
- Innate Immunity Group, Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, Szeged6726, Hungary
| | - Rebecca L. Tarnopol
- Department of Plant and Microbial Biology, University of California, Berkeley, CA94720
| | - Edit Ábrahám
- MTA SZBK Lendület Laboratory of Cell Cycle Regulation, Institute of Biochemistry, Biological Research Centre, Eötvös Loránd Research Network, Szeged6726, Hungary
| | - Zsuzsanna Darula
- Single Cell Omics Advanced Core Facility, Hungarian Centre of Excellence for Molecular Medicine, Szeged6728, Hungary
- Laboratory of Proteomics Research, Biological Research Centre, Eötvös Loránd Research Network, Szeged6726, Hungary
| | | | - Josephine A. Tamsil
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Saron M. Akalu
- Department of Integrative Biology, University of California, Berkeley, CA94720
| | - István Andó
- Innate Immunity Group, Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, Szeged6726, Hungary
| | - Noah K. Whiteman
- Department of Integrative Biology, University of California, Berkeley, CA94720
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA94720
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Li J, An Z, Luo J, Zhu X, Wang L, Zhang K, Li D, Ji J, Niu L, Gao X, Cui J. Parasitization of Aphis gossypii Glover by Binodoxys communis Gahan Causes Shifts in the Ovarian Bacterial Microbiota. INSECTS 2023; 14:314. [PMID: 37103129 PMCID: PMC10142764 DOI: 10.3390/insects14040314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 03/23/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND Aphis gossypii Glover is an important agricultural pest distributed worldwide. Binodoxys communis Gahan is the main parasitoid wasp of A. gossypii. Previous studies have shown that parasitization causes reduced egg production in A. gossypii, but the effects of parasitism on the symbiotic bacteria in the host ovaries are unknown. RESULTS In this study, we analyzed the microbial communities in the ovaries of A. gossypii without and after parasitization. Whether parasitized or not, Buchnera was the dominant genus of symbiotic bacteria in the ovaries, followed by facultative symbionts including Arsenophonus, Pseudomonas, and Acinetobacter. The relative abundance of Buchnera in the aphid ovary increased after parasitization for 1 d in both third-instar nymph and adult stages, but decreased after parasitization for 3 d. The shifts in the relative abundance of Arsenophonus in both stages were the same as those observed for Buchnera. In addition, the relative abundance of Serratia remarkably decreased after parasitization for 1 d and increased after parasitization for 3 d. A functional predictive analysis of the control and parasitized ovary microbiomes revealed that pathways primarily enriched in parasitization were "amino acid transport and metabolism" and "energy production and conversion." Finally, RT-qPCR analysis was performed on Buchnera, Arsenophonus, and Serratia. The results of RT-qPCR were the same as the results of 16S rDNA sequencing. CONCLUSIONS These results provide a framework for investigating shifts in the microbial communities in host ovaries, which may be responsible for reduced egg production in aphids. These findings also broaden our understanding of the interactions among aphids, parasitoid wasps, and endosymbionts.
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Affiliation(s)
- Jinming Li
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Zhe An
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Junyu Luo
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Xiangzhen Zhu
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Li Wang
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Kaixin Zhang
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Dongyang Li
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Jichao Ji
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Lin Niu
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Xueke Gao
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Jinjie Cui
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
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Higashi CHV, Nichols WL, Chevignon G, Patel V, Allison SE, Kim KL, Strand MR, Oliver KM. An aphid symbiont confers protection against a specialized RNA virus, another increases vulnerability to the same pathogen. Mol Ecol 2023; 32:936-950. [PMID: 36458425 PMCID: PMC10107813 DOI: 10.1111/mec.16801] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022]
Abstract
Insects often harbour heritable symbionts that provide defence against specialized natural enemies, yet little is known about symbiont protection when hosts face simultaneous threats. In pea aphids (Acyrthosiphon pisum), the facultative endosymbiont Hamiltonella defensa confers protection against the parasitoid, Aphidius ervi, and Regiella insecticola protects against aphid-specific fungal pathogens, including Pandora neoaphidis. Here, we investigated whether these two common aphid symbionts protect against a specialized virus A. pisum virus (APV), and whether their antifungal and antiparasitoid services are impacted by APV infection. We found that APV imposed large fitness costs on symbiont-free aphids and these costs were elevated in aphids also housing H. defensa. In contrast, APV titres were significantly reduced and costs to APV infection were largely eliminated in aphids with R. insecticola. To our knowledge, R. insecticola is the first aphid symbiont shown to protect against a viral pathogen, and only the second arthropod symbiont reported to do so. In contrast, APV infection did not impact the protective services of either R. insecticola or H. defensa. To better understand APV biology, we produced five genomes and examined transmission routes. We found that moderate rates of vertical transmission, combined with horizontal transfer through food plants, were the major route of APV spread, although lateral transfer by parasitoids also occurred. Transmission was unaffected by facultative symbionts. In summary, the presence and species identity of facultative symbionts resulted in highly divergent outcomes for aphids infected with APV, while not impacting defensive services that target other enemies. These findings add to the diverse phenotypes conferred by aphid symbionts, and to the growing body of work highlighting extensive variation in symbiont-mediated interactions.
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Affiliation(s)
| | - William L Nichols
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Germain Chevignon
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Vilas Patel
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Suzanne E Allison
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Kyungsun Lee Kim
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Michael R Strand
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Kerry M Oliver
- Department of Entomology, University of Georgia, Georgia, Athens, USA
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7
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Ganesan R, Wierz JC, Kaltenpoth M, Flórez LV. How It All Begins: Bacterial Factors Mediating the Colonization of Invertebrate Hosts by Beneficial Symbionts. Microbiol Mol Biol Rev 2022; 86:e0012621. [PMID: 36301103 PMCID: PMC9769632 DOI: 10.1128/mmbr.00126-21] [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] [Indexed: 01/01/2023] Open
Abstract
Beneficial associations with bacteria are widespread across animals, spanning a range of symbiont localizations, transmission routes, and functions. While some of these associations have evolved into obligate relationships with permanent symbiont localization within the host, the majority require colonization of every host generation from the environment or via maternal provisions. Across the broad diversity of host species and tissue types that beneficial bacteria can colonize, there are some highly specialized strategies for establishment yet also some common patterns in the molecular basis of colonization. This review focuses on the mechanisms underlying the early stage of beneficial bacterium-invertebrate associations, from initial contact to the establishment of the symbionts in a specific location of the host's body. We first reflect on general selective pressures that can drive the transition from a free-living to a host-associated lifestyle in bacteria. We then cover bacterial molecular factors for colonization in symbioses from both model and nonmodel invertebrate systems where these have been studied, including terrestrial and aquatic host taxa. Finally, we discuss how interactions between multiple colonizing bacteria and priority effects can influence colonization. Taking the bacterial perspective, we emphasize the importance of developing new experimentally tractable systems to derive general insights into the ecological factors and molecular adaptations underlying the origin and establishment of beneficial symbioses in animals.
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Affiliation(s)
- Ramya Ganesan
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Jürgen C. Wierz
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Martin Kaltenpoth
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Laura V. Flórez
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Plant and Environmental Sciences, Section for Organismal Biology, University of Copenhagen, Copenhagen, Denmark
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Camus MF, Alexander-Lawrie B, Sharbrough J, Hurst GDD. Inheritance through the cytoplasm. Heredity (Edinb) 2022; 129:31-43. [PMID: 35525886 PMCID: PMC9273588 DOI: 10.1038/s41437-022-00540-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/11/2022] Open
Abstract
Most heritable information in eukaryotic cells is encoded in the nuclear genome, with inheritance patterns following classic Mendelian segregation. Genomes residing in the cytoplasm, however, prove to be a peculiar exception to this rule. Cytoplasmic genetic elements are generally maternally inherited, although there are several exceptions where these are paternally, biparentally or doubly-uniparentally inherited. In this review, we examine the diversity and peculiarities of cytoplasmically inherited genomes, and the broad evolutionary consequences that non-Mendelian inheritance brings. We first explore the origins of vertical transmission and uniparental inheritance, before detailing the vast diversity of cytoplasmic inheritance systems across Eukaryota. We then describe the evolution of genomic organisation across lineages, how this process has been shaped by interactions with the nuclear genome and population genetics dynamics. Finally, we discuss how both nuclear and cytoplasmic genomes have evolved to co-inhabit the same host cell via one of the longest symbiotic processes, and all the opportunities for intergenomic conflict that arise due to divergence in inheritance patterns. In sum, we cannot understand the evolution of eukaryotes without understanding hereditary symbiosis.
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Affiliation(s)
- M Florencia Camus
- Department of Genetics, Evolution and Environment, University College London, London, UK.
| | | | - Joel Sharbrough
- Biology Department, New Mexico Institute of Mining and Technology, Socorro, NM, USA
| | - Gregory D D Hurst
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, England
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Whiteman NK. Evolution in small steps and giant leaps. Evolution 2022; 76:67-77. [PMID: 35040122 PMCID: PMC9387839 DOI: 10.1111/evo.14432] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/28/2021] [Accepted: 01/03/2022] [Indexed: 02/03/2023]
Abstract
The first Editor of Evolution was Ernst Mayr. His foreword to the first issue of Evolution published in 1947 framed evolution as a "problem of interaction" that was just beginning to be studied in this broad context. First, I explore progress and prospects on understanding the subsidiary interactions identified by Mayr, including interactions between parts of organisms, between individuals and populations, between species, and between the organism and its abiotic environment. Mayr's overall "problem of interaction" framework is examined in the context of coevolution within and among levels of biological organization. This leads to a comparison in the relative roles of biotic versus abiotic agents of selection and fluctuating versus directional selection, followed by stabilizing selection in shaping the genomic architecture of adaptation. Oligogenic architectures may be typical for traits shaped more by fluctuating selection and biotic selection. Conversely, polygenic architectures may be typical for traits shaped more by directional followed by stabilizing selection and abiotic selection. The distribution of effect sizes and turnover dynamics of adaptive alleles in these scenarios deserves further study. Second, I review two case studies on the evolution of acquired toxicity in animals, one involving cardiac glycosides obtained from plants and one involving bacterial virulence factors horizontally transferred to animals. The approaches used in these studies and the results gained directly flow from Mayr's vision of an evolutionary biology that revolves around the "problem of interaction."
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Affiliation(s)
- Noah K. Whiteman
- Department of Integrative Biology, University of California, Berkeley, California 94720,Department of Molecular and Cell Biology, University of California, Berkeley, California 94720,
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