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Arnqvist G, Rowe L. Ecology, the pace-of-life, epistatic selection and the maintenance of genetic variation in life-history genes. Mol Ecol 2023; 32:4713-4724. [PMID: 37386734 DOI: 10.1111/mec.17062] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 06/09/2023] [Accepted: 06/19/2023] [Indexed: 07/01/2023]
Abstract
Evolutionary genetics has long struggled with understanding how functional genes under selection remain polymorphic in natural populations. Taking as a starting point that natural selection is ultimately a manifestation of ecological processes, we spotlight an underemphasized and potentially ubiquitous ecological effect that may have fundamental effects on the maintenance of genetic variation. Negative frequency dependency is a well-established emergent property of density dependence in ecology, because the relative profitability of different modes of exploiting or utilizing limiting resources tends to be inversely proportional to their frequency in a population. We suggest that this may often generate negative frequency-dependent selection (NFDS) on major effect loci that affect rate-dependent physiological processes, such as metabolic rate, that are phenotypically manifested as polymorphism in pace-of-life syndromes. When such a locus under NFDS shows stable intermediate frequency polymorphism, this should generate epistatic selection potentially involving large numbers of loci with more minor effects on life-history (LH) traits. When alternative alleles at such loci show sign epistasis with a major effect locus, this associative NFDS will promote the maintenance of polygenic variation in LH genes. We provide examples of the kind of major effect loci that could be involved and suggest empirical avenues that may better inform us on the importance and reach of this process.
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Affiliation(s)
- Göran Arnqvist
- Animal Ecology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Locke Rowe
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
- Swedish Collegium of Advanced Study, Uppsala, Sweden
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2
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Nguyen THM, Sondhi S, Ziesel A, Paliwal S, Fiumera HL. Mitochondrial-nuclear coadaptation revealed through mtDNA replacements in Saccharomyces cerevisiae. BMC Evol Biol 2020; 20:128. [PMID: 32977769 PMCID: PMC7517635 DOI: 10.1186/s12862-020-01685-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/07/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mitochondrial function requires numerous genetic interactions between mitochondrial- and nuclear- encoded genes. While selection for optimal mitonuclear interactions should result in coevolution between both genomes, evidence for mitonuclear coadaptation is challenging to document. Genetic models where mitonuclear interactions can be explored are needed. RESULTS We systematically exchanged mtDNAs between 15 Saccharomyces cerevisiae isolates from a variety of ecological niches to create 225 unique mitochondrial-nuclear genotypes. Analysis of phenotypic profiles confirmed that environmentally-sensitive interactions between mitochondrial and nuclear genotype contributed to growth differences. Exchanges of mtDNAs between strains of the same or different clades were just as likely to demonstrate mitonuclear epistasis although epistatic effect sizes increased with genetic distances. Strains with their original mtDNAs were more fit than strains with synthetic mitonuclear combinations when grown in media that resembled isolation habitats. CONCLUSIONS This study shows that natural variation in mitonuclear interactions contributes to fitness landscapes. Multiple examples of coadapted mitochondrial-nuclear genotypes suggest that selection for mitonuclear interactions may play a role in helping yeasts adapt to novel environments and promote coevolution.
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Affiliation(s)
- Tuc H M Nguyen
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA
| | - Sargunvir Sondhi
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA
| | - Andrew Ziesel
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA
| | - Swati Paliwal
- Department of Bioscience and Biotechnology, Banasthali Vidyapith, Rajasthan, India
| | - Heather L Fiumera
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA.
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3
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Gangloff EJ, Schwartz TS, Klabacka R, Huebschman N, Liu AY, Bronikowski AM. Mitochondria as central characters in a complex narrative: Linking genomics, energetics, pace-of-life, and aging in natural populations of garter snakes. Exp Gerontol 2020; 137:110967. [DOI: 10.1016/j.exger.2020.110967] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/11/2020] [Accepted: 05/01/2020] [Indexed: 12/18/2022]
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Vaught RC, Voigt S, Dobler R, Clancy DJ, Reinhardt K, Dowling DK. Interactions between cytoplasmic and nuclear genomes confer sex-specific effects on lifespan in Drosophila melanogaster. J Evol Biol 2020; 33:694-713. [PMID: 32053259 DOI: 10.1111/jeb.13605] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/04/2020] [Accepted: 02/06/2020] [Indexed: 12/19/2022]
Abstract
Genetic variation outside of the cell nucleus can affect the phenotype. The cytoplasm is home to the mitochondria, and in arthropods often hosts intracellular bacteria such as Wolbachia. Although numerous studies have implicated epistatic interactions between cytoplasmic and nuclear genetic variation as mediators of phenotypic expression, two questions remain. Firstly, it remains unclear whether outcomes of cyto-nuclear interactions will manifest differently across the sexes, as might be predicted given that cytoplasmic genomes are screened by natural selection only through females as a consequence of their maternal inheritance. Secondly, the relative contribution of mitochondrial genetic variation to other cytoplasmic sources of variation, such as Wolbachia infection, in shaping phenotypic outcomes of cyto-nuclear interactions remains unknown. Here, we address these questions, creating a fully crossed set of replicated cyto-nuclear populations derived from three geographically distinct populations of Drosophila melanogaster, measuring the lifespan of males and females from each population. We observed that cyto-nuclear interactions shape lifespan and that the outcomes of these interactions differ across the sexes. Yet, we found no evidence that placing the cytoplasms from one population alongside the nuclear background of others (generating putative cyto-nuclear mismatches) leads to decreased lifespan in either sex. Although it was difficult to partition mitochondrial from Wolbachia effects, our results suggest at least some of the cytoplasmic genotypic contribution to lifespan was directly mediated by an effect of sequence variation in the mtDNA. Future work should explore the degree to which cyto-nuclear interactions result in sex differences in the expression of other components of organismal life history.
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Affiliation(s)
- Rebecca C Vaught
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Susanne Voigt
- Faculty of Biology, Applied Zoology, TU Dresden, Dresden, Germany
| | - Ralph Dobler
- Faculty of Biology, Applied Zoology, TU Dresden, Dresden, Germany
| | - David J Clancy
- Division of Biomedical and Life Sciences, School of Health and Medicine, Lancaster University, Lancaster, UK
| | - Klaus Reinhardt
- Faculty of Biology, Applied Zoology, TU Dresden, Dresden, Germany
| | - Damian K Dowling
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
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Havird JC, Weaver RJ, Milani L, Ghiselli F, Greenway R, Ramsey AJ, Jimenez AG, Dowling DK, Hood WR, Montooth KL, Estes S, Schulte PM, Sokolova IM, Hill GE. Beyond the Powerhouse: Integrating Mitonuclear Evolution, Physiology, and Theory in Comparative Biology. Integr Comp Biol 2020; 59:856-863. [PMID: 31504533 DOI: 10.1093/icb/icz132] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Eukaryotes are the outcome of an ancient symbiosis and as such, eukaryotic cells fundamentally possess two genomes. As a consequence, gene products encoded by both nuclear and mitochondrial genomes must interact in an intimate and precise fashion to enable aerobic respiration in eukaryotes. This genomic architecture of eukaryotes is proposed to necessitate perpetual coevolution between the nuclear and mitochondrial genomes to maintain coadaptation, but the presence of two genomes also creates the opportunity for intracellular conflict. In the collection of papers that constitute this symposium volume, scientists working in diverse organismal systems spanning vast biological scales address emerging topics in integrative, comparative biology in light of mitonuclear interactions.
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Affiliation(s)
- Justin C Havird
- Department of Integrative Biology, University of Texas, Austin, TX 78712, USA
| | - Ryan J Weaver
- Department of Integrative Biology, University of Texas, Austin, TX 78712, USA.,Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Liliana Milani
- Department of Biological, Geological and Environmental Sciences (BiGeA), University of Bologna, Bologna, 40126, Italy
| | - Fabrizio Ghiselli
- Department of Biological, Geological and Environmental Sciences (BiGeA), University of Bologna, Bologna, 40126, Italy
| | - Ryan Greenway
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Adam J Ramsey
- Department of Biological Sciences, University of Memphis, Memphis, TN 38152, USA
| | - Ana G Jimenez
- Department of Biology, Colgate University, Hamilton, NY 13346, USA
| | - Damian K Dowling
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Wendy R Hood
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Kristi L Montooth
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68502, USA
| | - Suzanne Estes
- Department of Biology, Portland State University, Portland, OR 97201, USA
| | - Patricia M Schulte
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Inna M Sokolova
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, Rostock, Germany.,Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
| | - Geoffrey E Hill
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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Healy TM, Brennan RS, Whitehead A, Schulte PM. Mitochondria, sex and variation in routine metabolic rate. Mol Ecol 2019; 28:4608-4619. [PMID: 31529542 DOI: 10.1111/mec.15244] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 09/12/2019] [Indexed: 12/14/2022]
Abstract
Variation in the metabolic costs associated with organismal maintenance may play a key role in determining fitness, and thus these differences among individuals are likely to be subject to natural selection. Although the evolvability of maintenance metabolism depends on its underlying genetic architecture, relatively little is known about the nature of genetic variation that underlies this trait. To address this, we measured variation in routine metabolic rate (ṀO2 routine ), an index of maintenance metabolism, within and among three populations of Atlantic killifish, Fundulus heteroclitus, including a population from a region of genetic admixture between two subspecies. Polygenic association tests among individuals from the admixed population identified 54 single nucleotide polymorphisms (SNPs) that were associated with ṀO2 routine , and these SNPs accounted for 43% of interindividual variation in this trait. However, genetic associations with ṀO2 routine involved different SNPs if females and males were analysed separately, and there was a sex-dependent effect of mitochondrial genotype on variation in routine metabolism. These results imply that there are sex-specific genetic mechanisms, and potential mitonuclear interactions, that underlie variation in ṀO2 routine . Additionally, there was evidence for epistatic interactions between 17% of the possible pairs of trait-associated SNPs, suggesting that epistatic effects on ṀO2 routine are common. These data demonstrate not only that phenotypic variation in this ecologically important trait has a polygenic basis with considerable epistasis among loci, but also that these underlying genetic mechanisms, and particularly the role of mitochondrial genotype, may be sex-specific.
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Affiliation(s)
- Timothy M Healy
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Reid S Brennan
- Department of Environmental Toxicology, University of California Davis, Davis, CA, USA
| | - Andrew Whitehead
- Department of Environmental Toxicology, University of California Davis, Davis, CA, USA
| | - Patricia M Schulte
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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