1
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McCaw BA, Leonard AM, Stevenson TJ, Lancaster LT. A role of epigenetic mechanisms in regulating female reproductive responses to temperature in a pest beetle. INSECT MOLECULAR BIOLOGY 2024. [PMID: 38864655 DOI: 10.1111/imb.12933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 05/23/2024] [Indexed: 06/13/2024]
Abstract
Many species are threatened by climate change and must rapidly respond to survive in changing environments. Epigenetic modifications, such as DNA methylation, can facilitate plastic responses by regulating gene expression in response to environmental cues. Understanding epigenetic responses is therefore essential for predicting species' ability to rapidly adapt in the context of global environmental change. Here, we investigated the functional significance of different methylation-associated cellular processes on temperature-dependent life history in seed beetles, Callosobruchus maculatus Fabricius 1775 (Coleoptera: Bruchidae). We assessed changes under thermal stress in (1) DNA methyltransferase (Dnmt1 and Dnmt2) expression levels, (2) genome-wide methylation and (3) reproductive performance, with (2) and (3) following treatment with 3-aminobenzamide (3AB) and zebularine (Zeb) over two generations. These drugs are well-documented to alter DNA methylation across the tree of life. We found that Dnmt1 and Dnmt2 were expressed throughout the body in males and females, but were highly expressed in females compared with males and exhibited temperature dependence. However, whole-genome methylation did not significantly vary with temperature, and only marginally or inconclusively with drug treatment. Both 3AB and Zeb led to profound temperature-dependent shifts in female reproductive life history trade-off allocation, often increasing fitness compared with control beetles. Mismatch between magnitude of treatment effects on DNA methylation versus life history effects suggest potential of 3AB and Zeb to alter reproductive trade-offs via changes in DNA repair and recycling processes, rather than or in addition to (subtle) changes in DNA methylation. Together, our results suggest that epigenetic mechanisms relating to Dnmt expression, DNA repair and recycling pathways, and possibly DNA methylation, are strongly implicated in modulating insect life history trade-offs in response to temperature change.
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Affiliation(s)
- Beth A McCaw
- School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland
| | - Aoife M Leonard
- Centre for Evolutionary Hologenomics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Tyler J Stevenson
- School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland
| | - Lesley T Lancaster
- School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland
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2
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Baur J, Koppik M, Savković U, Đorđević M, Stojkovic B, Berger D. Coevolution of longevity and female germline maintenance. Proc Biol Sci 2024; 291:20240532. [PMID: 38864321 DOI: 10.1098/rspb.2024.0532] [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: 11/24/2023] [Accepted: 04/11/2024] [Indexed: 06/13/2024] Open
Abstract
An often-overlooked aspect of life-history optimization is the allocation of resources to protect the germline and secure safe transmission of genetic information. While failure to do so renders significant fitness consequences in future generations, germline maintenance comes with substantial costs. Thus, germline allocation should trade off with other life-history decisions and be optimized in accordance with an organism's reproductive schedule. Here, we tested this hypothesis by studying germline maintenance in lines of seed beetle, selected for early (E) or late (L) reproduction for 350 and 240 generations, respectively. Female animals provide maintenance and screening of male gametes in their reproductive tract and oocytes. Here, we reveal the ability of young and aged E- and L-females to provide this form of germline maintenance by mating them to males with ejaculates with artificially elevated levels of protein and DNA damage. We find that germline maintenance in E-females peaks at young age and then declines, while the opposite is true for L-females, in accordance with the age of reproduction in the respective regime. These findings identify the central role of allocation to secure germline integrity in life-history evolution and highlight how females can play a crucial role in mitigating the effects of male germline decisions on mutation rate and offspring quality.
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Affiliation(s)
- Julian Baur
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Mareike Koppik
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
- Animal Ecology, Department of Zoology, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Uroš Savković
- Department of Evolutionary Biology, Institute for Biological Research "Siniša Stanković", National Institute of the Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, Belgrade 11000, Serbia
| | - Mirko Đorđević
- Department of Evolutionary Biology, Institute for Biological Research "Siniša Stanković", National Institute of the Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, Belgrade 11000, Serbia
| | - Biljana Stojkovic
- Institute of Zoology, Chair of Genetics and Evolution, Faculty of Biology, Studentski trg 16, 11000 Belgrade, Serbia
| | - David Berger
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
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3
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Baur J, Zwoinska M, Koppik M, Snook RR, Berger D. Heat stress reveals a fertility debt owing to postcopulatory sexual selection. Evol Lett 2024; 8:101-113. [PMID: 38370539 PMCID: PMC10872150 DOI: 10.1093/evlett/qrad007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 01/21/2023] [Accepted: 02/21/2023] [Indexed: 02/20/2024] Open
Abstract
Climates are changing rapidly, demanding equally rapid adaptation of natural populations. Whether sexual selection can aid such adaptation is under debate; while sexual selection should promote adaptation when individuals with high mating success are also best adapted to their local surroundings, the expression of sexually selected traits can incur costs. Here we asked what the demographic consequences of such costs may be once climates change to become harsher and the strength of natural selection increases. We first adopted a classic life history theory framework, incorporating a trade-off between reproduction and maintenance, and applied it to the male germline to generate formalized predictions for how an evolutionary history of strong postcopulatory sexual selection (sperm competition) may affect male fertility under acute adult heat stress. We then tested these predictions by assessing the thermal sensitivity of fertility (TSF) in replicated lineages of seed beetles maintained for 68 generations under three alternative mating regimes manipulating the opportunity for sexual and natural selection. In line with the theoretical predictions, we find that males evolving under strong sexual selection suffer from increased TSF. Interestingly, females from the regime under strong sexual selection, who experienced relaxed selection on their own reproductive effort, had high fertility in benign settings but suffered increased TSF, like their brothers. This implies that female fertility and TSF evolved through genetic correlation with reproductive traits sexually selected in males. Paternal but not maternal heat stress reduced offspring fertility with no evidence for adaptive transgenerational plasticity among heat-exposed offspring, indicating that the observed effects may compound over generations. Our results suggest that trade-offs between fertility and traits increasing success in postcopulatory sexual selection can be revealed in harsh environments. This can put polyandrous species under immediate risk during extreme heat waves expected under future climate change.
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Affiliation(s)
- Julian Baur
- Department of Ecology and Genetics, Division of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Martyna Zwoinska
- Department of Ecology and Genetics, Division of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Mareike Koppik
- Department of Ecology and Genetics, Division of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Zoology, Animal Ecology, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Rhonda R Snook
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - David Berger
- Department of Ecology and Genetics, Division of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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4
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Sorel MH, Murdoch AR, Zabel RW, Kamphaus CM, Buhle ER, Scheuerell MD, Converse SJ. Effects of population density and environmental conditions on life-history prevalence in a migratory fish. Ecol Evol 2023; 13:e10087. [PMID: 37234292 PMCID: PMC10206029 DOI: 10.1002/ece3.10087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/28/2023] [Accepted: 04/26/2023] [Indexed: 05/27/2023] Open
Abstract
Individual variation in life-history traits can have important implications for the ability of populations to respond to environmental variability and change. In migratory animals, flexibility in the timing of life-history events, such as juvenile emigration from natal areas, can influence the effects of population density and environmental conditions on habitat use and population dynamics. We evaluated the functional relationships between population density and environmental covariates and the abundance of juveniles expressing different life-history pathways in a migratory fish, Chinook salmon (Oncorhynchus tshawytscha), in the Wenatchee River basin in Washington State, USA. We found that the abundance of younger emigrants from natal streams was best described by an accelerating or near-linear function of spawners, whereas the abundance of older emigrants was best described by a decelerating function of spawners. This supports the hypothesis that emigration timing varies in response to density in natal areas, with younger-emigrating life-history pathways comprising a larger proportion of emigrants when densities of conspecifics are high. We also observed positive relationships between winter stream discharge and abundance of younger emigrants, supporting the hypothesis that habitat conditions can also influence the prevalence of different life-history pathways. Our results suggest that early emigration, and a resultant increase in the use of downstream rearing habitats, may increase at higher population densities and with greater winter precipitation. Winter precipitation is projected to increase in this system due to climate warming. Characterizing relationships between life-history prevalence and environmental conditions may improve our understanding of species habitat requirements and is a first step in understanding the dynamics of species with diverse life-history strategies. As environmental conditions change-due to climate change, management, or other factors-resultant life-history changes are likely to have important demographic implications that will be challenging to predict when life-history diversity is not accounted for in population models.
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Affiliation(s)
- Mark H. Sorel
- Washington Cooperative Fish and Wildlife Research Unit, School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashingtonUSA
| | | | - Richard W. Zabel
- Northwest Fisheries Science Center, National Marine Fisheries ServiceNational Oceanic and Atmospheric AssociationSeattleWashingtonUSA
| | | | - Eric R. Buhle
- Northwest Fisheries Science Center, National Marine Fisheries ServiceNational Oceanic and Atmospheric AssociationSeattleWashingtonUSA
- Mt. Hood EnvironmentalSandyOregonUSA
| | - Mark D. Scheuerell
- U.S. Geological Survey, Washington Cooperative Fish and Wildlife Research Unit, School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashingtonUSA
| | - Sarah J. Converse
- U.S. Geological Survey, Washington Cooperative Fish and Wildlife Research Unit, School of Environmental and Forest Sciences & School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashingtonUSA
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5
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Ivimey-Cook ER, Murray DS, de Coriolis JC, Edden N, Immler S, Maklakov AA. Fasting increases investment in soma upon refeeding at the cost of gamete quality in zebrafish. Proc Biol Sci 2023; 290:20221556. [PMID: 37040805 PMCID: PMC10089719 DOI: 10.1098/rspb.2022.1556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023] Open
Abstract
Fasting increases lifespan in invertebrates, improves biomarkers of health in vertebrates and is increasingly proposed as a promising route to improve human health. Nevertheless, little is known about how fasted animals use resources upon refeeding, and how such decisions affect putative trade-offs between somatic growth and repair, reproduction and gamete quality. Such fasting-induced trade-offs are based on strong theoretical foundations and have been recently discovered in invertebrates, but the data on vertebrates are lacking. Here, we report that fasted female zebrafish, Danio rerio, increase investment in soma upon refeeding, but it comes at a cost of egg quality. Specifically, an increase in fin regrowth was accompanied by a reduction in 24 h post-fertilization offspring survival. Refed males showed a reduction in sperm velocity and impaired 24 h post-fertilization offspring survival. These findings underscore the necessity of considering the impact on reproduction when assessing evolutionary and biomedical implications of lifespan-extending treatments in females and males and call for careful evaluation of the effects of intermittent fasting on fertilization.
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Affiliation(s)
- Edward R Ivimey-Cook
- School of Biological Sciences, University of East Anglia, Norfolk NR4 7TJ, UK
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - David S Murray
- Collaborative Centre for Sustainable Use of the Seas (CCSUS), School of Environmental Sciences, University of East Anglia, Norfolk NR4 7TJ, UK
- The Centre for Environment, Fisheries and Aquaculture Science (Cefas), Lowestoft, Suffolk NR33 0HT, UK
| | | | - Nathan Edden
- School of Biological Sciences, University of East Anglia, Norfolk NR4 7TJ, UK
| | - Simone Immler
- School of Biological Sciences, University of East Anglia, Norfolk NR4 7TJ, UK
| | - Alexei A Maklakov
- School of Biological Sciences, University of East Anglia, Norfolk NR4 7TJ, UK
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6
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Duxbury EML, Carlsson H, Sales K, Sultanova Z, Immler S, Chapman T, Maklakov AA. Multigenerational downregulation of insulin/IGF-1 signaling in adulthood improves lineage survival, reproduction, and fitness in Caenorhabditis elegans supporting the developmental theory of ageing. Evolution 2022; 76:2829-2845. [PMID: 36199198 PMCID: PMC10092551 DOI: 10.1111/evo.14640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 07/18/2022] [Accepted: 09/08/2022] [Indexed: 01/22/2023]
Abstract
Adulthood-only downregulation of insulin/IGF-1 signaling (IIS), an evolutionarily conserved pathway regulating resource allocation between somatic maintenance and reproduction, increases life span without fecundity cost in the nematode, Caenorhabditis elegans. However, long-term multigenerational effects of reduced IIS remain unexplored and are proposed to carry costs for offspring quality. To test this hypothesis, we ran a mutation accumulation (MA) experiment and downregulated IIS in half of the 400 MA lines by silencing daf-2 gene expression using RNA interference (RNAi) across 40 generations. Contrary to the prediction, adulthood-only daf-2 RNAi reduced extinction of MA lines both under UV-induced and spontaneous MA. Fitness of the surviving UV-induced MA lines was higher under daf-2 RNAi. Reduced IIS increased intergenerational F1 offspring fitness under UV stress but had no quantifiable transgenerational effects. Functional hrde-1 was required for the benefits of multigenerational daf-2 RNAi. Overall, we found net benefit to fitness from multigenerational reduction of IIS and the benefits became more apparent under stress. Because reduced daf-2 expression during development carries fitness costs, we suggest that our findings are best explained by the developmental theory of ageing, which maintains that the decline in the force of selection with age results in poorly regulated gene expression in adulthood.
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Affiliation(s)
- Elizabeth M L Duxbury
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
| | - Hanne Carlsson
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
| | - Kris Sales
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
| | - Zahida Sultanova
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
| | - Simone Immler
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
| | - Tracey Chapman
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
| | - Alexei A Maklakov
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
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7
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Multivariate selection and the making and breaking of mutational pleiotropy. Evol Ecol 2022. [DOI: 10.1007/s10682-022-10195-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractThe role of mutations have been subject to many controversies since the formation of the Modern Synthesis of evolution in the early 1940ties. Geneticists in the early half of the twentieth century tended to view mutations as a limiting factor in evolutionary change. In contrast, natural selection was largely viewed as a “sieve” whose main role was to sort out the unfit but which could not create anything novel alone. This view gradually changed with the development of mathematical population genetics theory, increased appreciation of standing genetic variation and the discovery of more complex forms of selection, including balancing selection. Short-term evolutionary responses to selection are mainly influenced by standing genetic variation, and are predictable to some degree using information about the genetic variance–covariance matrix (G) and the strength and form of selection (e. g. the vector of selection gradients, β). However, predicting long-term evolution is more challenging, and requires information about the nature and supply of novel mutations, summarized by the mutational variance–covariance matrix (M). Recently, there has been increased attention to the role of mutations in general and M in particular. Some evolutionary biologists argue that evolution is largely mutation-driven and claim that mutation bias frequently results in mutation-biased adaptation. Strong similarities between G and M have also raised questions about the non-randomness of mutations. Moreover, novel mutations are typically not isotropic in their phenotypic effects and mutational pleiotropy is common. Here I discuss the evolutionary origin and consequences of mutational pleiotropy and how multivariate selection directly shapes G and indirectly M through changed epistatic relationships. I illustrate these ideas by reviewing recent literature and models about correlational selection, evolution of G and M, sexual selection and the fitness consequences of sexual antagonism.
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8
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Sanghvi K, Iglesias‐Carrasco M, Zajitschek F, Kruuk LEB, Head ML. Effects of developmental and adult environments on ageing. Evolution 2022; 76:1868-1882. [PMID: 35819127 PMCID: PMC9543291 DOI: 10.1111/evo.14567] [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] [Received: 10/15/2021] [Revised: 06/03/2022] [Accepted: 06/28/2022] [Indexed: 01/22/2023]
Abstract
Developmental and adult environments can interact in complex ways to influence the fitness of individuals. Most studies investigating effects of the environment on fitness focus on environments experienced and traits expressed at a single point in an organism's life. However, environments vary with time, so the effects of the environments that organisms experience at different ages may interact to affect how traits change throughout life. Here, we test whether thermal stress experienced during development leads individuals to cope better with thermal stress as adults. We manipulated temperature during both development and adulthood and measured a range of life-history traits, including senescence, in male and female seed beetles (Callosobruchus maculatus). We found that thermal stress during development reduced adult reproductive performance of females. In contrast, life span and age-dependent mortality were affected more by adult than developmental environments, with high adult temperatures decreasing longevity and increasing age-dependent mortality. Aside from an interaction between developmental and adult environments to affect age-dependent changes in male weight, we did not find any evidence of a beneficial acclimation response to developmental thermal stress. Overall, our results show that effects of developmental and adult environments can be both sex and trait specific, and that a full understanding of how environments interact to affect fitness and ageing requires the integrated study of conditions experienced during different stages of ontogeny.
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Affiliation(s)
- Krish Sanghvi
- Reserach School of BiologyAustralian National UniversityCanberraACT2601Australia
| | | | - Felix Zajitschek
- School of Biology Earth and Environmental SciencesUniversity of New South WalesSydneyNSW2052Australia
| | - Loeske E. B. Kruuk
- Reserach School of BiologyAustralian National UniversityCanberraACT2601Australia
| | - Megan L. Head
- Reserach School of BiologyAustralian National UniversityCanberraACT2601Australia
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9
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Tarkington J, Zufall RA. Temperature affects the repeatability of evolution in the microbial eukaryote Tetrahymena thermophila. Ecol Evol 2021; 11:13139-13152. [PMID: 34646458 PMCID: PMC8495795 DOI: 10.1002/ece3.8036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 11/09/2022] Open
Abstract
Evolutionary biologists have long sought to understand what factors affect the repeatability of adaptive outcomes. To better understand the role of temperature in determining the repeatability of adaptive trajectories, we evolved populations of different genotypes of the ciliate Tetrahymena thermophila at low and high temperatures and followed changes in growth rate over 6,500 generations. As expected, growth rate increased with a decelerating rate for all populations; however, there were differences in the patterns of evolution at the two temperatures. The growth rates of the different genotypes tended to converge as evolution proceeded at both temperatures, but this convergence was quicker and more pronounced at the higher temperature. Additionally, over the first 4,000 generations we found greater repeatability of evolution, in terms of change in growth rate, among replicates of the same genotype at the higher temperature. Finally, we found limited evidence of trade-offs in fitness between temperatures, and an asymmetry in the correlated responses, whereby evolution in a high temperature increases growth rate at the lower temperature significantly more than the reverse. These results demonstrate the importance of temperature in determining the repeatability of evolutionary trajectories for the eukaryotic microbe Tetrahymena thermophila and may provide clues to how temperature affects evolution more generally.
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Affiliation(s)
- Jason Tarkington
- Department of Biology and BiochemistryUniversity of HoustonHoustonTXUSA
- Department of GeneticsStanford UniversityStanfordCAUSA
| | - Rebecca A. Zufall
- Department of Biology and BiochemistryUniversity of HoustonHoustonTXUSA
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10
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Waldvogel AM, Pfenninger M. Temperature dependence of spontaneous mutation rates. Genome Res 2021; 31:1582-1589. [PMID: 34301628 PMCID: PMC8415371 DOI: 10.1101/gr.275168.120] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 07/21/2021] [Indexed: 11/29/2022]
Abstract
Mutation is the source of genetic variation and the fundament of evolution. Temperature has long been suggested to have a direct impact on realized spontaneous mutation rates. If mutation rates vary in response to environmental conditions, such as the variation of the ambient temperature through space and time, they should no longer be described as species-specific constants. By combining mutation accumulation with whole-genome sequencing in a multicellular organism, we provide empirical support to reject the null hypothesis of a constant, temperature-independent mutation rate. Instead, mutation rates depended on temperature in a U-shaped manner with increasing rates toward both temperature extremes. This relation has important implications for mutation-dependent processes in molecular evolution, processes shaping the evolution of mutation rates, and even the evolution of biodiversity as such.
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Affiliation(s)
- Ann-Marie Waldvogel
- Senckenberg Biodiversity and Climate Research Centre, 60325 Frankfurt am Main, Germany
- Institute of Zoology, University of Cologne, 50674 Cologne, Germany
| | - Markus Pfenninger
- Senckenberg Biodiversity and Climate Research Centre, 60325 Frankfurt am Main, Germany
- LOEWE Centre for Translational Biodiversity Genomics, Senckenberg Biodiversity and Climate Research Centre, 60325 Frankfurt am Main, Germany
- Institute for Organismic and Molecular Evolution, Johannes Gutenberg University, 55128 Mainz, Germany
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11
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Dolby GA. Towards a unified framework to study causality in Earth-life systems. Mol Ecol 2021; 30:5628-5642. [PMID: 34427004 PMCID: PMC9292314 DOI: 10.1111/mec.16142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 07/17/2021] [Accepted: 08/20/2021] [Indexed: 01/04/2023]
Abstract
There is considerable interest in better understanding how earth processes shape the generation and distribution of life on Earth. This question, at its heart, is one of causation. In this article I propose that at a regional level, earth processes can be thought of as behaving somewhat deterministically and may have an organized effect on the diversification and distribution of species. However, the study of how landscape features shape biology is challenged by pseudocongruent or collinear variables. I demonstrate that causal structures can be used to depict the cause–effect relationships between earth processes and biological patterns using recent examples from the literature about speciation and species richness in montane settings. This application shows that causal diagrams can be used to better decipher the details of causal relationships by motivating new hypotheses. Additionally, the abstraction of this knowledge into structural equation metamodels can be used to formulate theory about relationships within Earth–life systems more broadly. Causal structures are a natural point of collaboration between biologists and Earth scientists, and their use can mitigate against the risk of misassigning causality within studies. My goal is that by applying causal theory through application of causal structures, we can build a systems‐level understanding of what landscape features or earth processes most shape the distribution and diversification of species, what types of organisms are most affected, and why.
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Affiliation(s)
- Greer A Dolby
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA.,Center for Mechanisms of Evolution, Arizona State University, Tempe, Arizona, USA
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12
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Ivimey-Cook E, Bricout S, Candela V, Maklakov AA, Berg EC. Inbreeding reduces fitness of seed beetles under thermal stress. J Evol Biol 2021; 34:1386-1396. [PMID: 34233049 PMCID: PMC9291971 DOI: 10.1111/jeb.13899] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/22/2021] [Accepted: 06/27/2021] [Indexed: 11/29/2022]
Abstract
Human‐induced environmental change can influence populations both at the global level through climatic warming and at the local level through habitat fragmentation. As populations become more isolated, they can suffer from high levels of inbreeding, which contributes to a reduction in fitness, termed inbreeding depression. However, it is still unclear if this increase in homozygosity also results in a corresponding increase in sensitivity to stressful conditions, which could intensify the already detrimental effects of environmental warming. Here, in a fully factorial design, we assessed the life‐long impact of increased inbreeding load and elevated temperature on key life history traits in the seed beetle, Callosobruchus maculatus. We found that beetles raised at higher temperatures had far reduced fitness and survival than beetles from control temperatures. Importantly, these negative effects were exacerbated in inbred beetles as a result of increased inbreeding load, with further detrimental effects manifesting on individual eclosion probability and lifetime reproductive success. These results reveal the harmful impact that increasing temperature and likelihood of habitat fragmentation due to anthropogenetic changes in environmental conditions could have on populations of organisms worldwide.
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Affiliation(s)
- Edward Ivimey-Cook
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Sophie Bricout
- Department of Computer Science, Mathematics, and Environmental Science, The American University of Paris, Paris, France
| | - Victoria Candela
- Department of Computer Science, Mathematics, and Environmental Science, The American University of Paris, Paris, France
| | - Alexei A Maklakov
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Elena C Berg
- Department of Computer Science, Mathematics, and Environmental Science, The American University of Paris, Paris, France
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13
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Bagchi B, Corbel Q, Khan I, Payne E, Banerji D, Liljestrand-Rönn J, Martinossi-Allibert I, Baur J, Sayadi A, Immonen E, Arnqvist G, Söderhäll I, Berger D. Sexual conflict drives micro- and macroevolution of sexual dimorphism in immunity. BMC Biol 2021; 19:114. [PMID: 34078377 PMCID: PMC8170964 DOI: 10.1186/s12915-021-01049-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/07/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Sexual dimorphism in immunity is believed to reflect sex differences in reproductive strategies and trade-offs between competing life history demands. Sexual selection can have major effects on mating rates and sex-specific costs of mating and may thereby influence sex differences in immunity as well as associated host-pathogen dynamics. Yet, experimental evidence linking the mating system to evolved sexual dimorphism in immunity are scarce and the direct effects of mating rate on immunity are not well established. Here, we use transcriptomic analyses, experimental evolution and phylogenetic comparative methods to study the association between the mating system and sexual dimorphism in immunity in seed beetles, where mating causes internal injuries in females. RESULTS We demonstrate that female phenoloxidase (PO) activity, involved in wound healing and defence against parasitic infections, is elevated relative to males. This difference is accompanied by concomitant sex differences in the expression of genes in the prophenoloxidase activating cascade. We document substantial phenotypic plasticity in female PO activity in response to mating and show that experimental evolution under enforced monogamy (resulting in low remating rates and reduced sexual conflict relative to natural polygamy) rapidly decreases female (but not male) PO activity. Moreover, monogamous females had evolved increased tolerance to bacterial infection unrelated to mating, implying that female responses to costly mating may trade off with other aspects of immune defence, an hypothesis which broadly accords with the documented sex differences in gene expression. Finally, female (but not male) PO activity shows correlated evolution with the perceived harmfulness of male genitalia across 12 species of seed beetles, suggesting that sexual conflict has a significant influence on sexual dimorphisms in immunity in this group of insects. CONCLUSIONS Our study provides insights into the links between sexual conflict and sexual dimorphism in immunity and suggests that selection pressures moulded by mating interactions can lead to a sex-specific mosaic of immune responses with important implications for host-pathogen dynamics in sexually reproducing organisms.
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Affiliation(s)
- Basabi Bagchi
- Department of Biology, Ashoka University, Sonipat, India
| | - Quentin Corbel
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain
| | - Imroze Khan
- Department of Biology, Ashoka University, Sonipat, India
| | - Ellen Payne
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | | | - Johanna Liljestrand-Rönn
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Ivain Martinossi-Allibert
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Julian Baur
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Ahmed Sayadi
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Chemistry, Biochemistry, Uppsala University, Uppsala, Sweden
| | - Elina Immonen
- Department of Ecology and Genetics, Program of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Göran Arnqvist
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Irene Söderhäll
- Department of Organismal Biology, Program of Comparative Physiology, Uppsala University, Uppsala, Sweden
| | - David Berger
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
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14
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Waheed A, Wang YP, Nkurikiyimfura O, Li WY, Liu ST, Lurwanu Y, Lu GD, Wang ZH, Yang LN, Zhan J. Effector Avr4 in Phytophthora infestans Escapes Host Immunity Mainly Through Early Termination. Front Microbiol 2021; 12:646062. [PMID: 34122360 PMCID: PMC8192973 DOI: 10.3389/fmicb.2021.646062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 03/19/2021] [Indexed: 11/13/2022] Open
Abstract
Effector genes play critical roles in the antagonistic interactions between plants and pathogens. However, knowledge of mutation mechanisms and evolutionary processes in effector genes and the contribution of climatic factors to the evolution of effector genes are fragmented but important in sustainable management of plant diseases and securing food supply under changing climates. Here, we used a population genetic approach to explore the evolution of the Avr4 gene in Phytophthora infestans, the causal agent of potato blight. We found that the Avr4 gene exhibited a high genetic diversity generated by point mutation and sequence deletion. Frameshifts caused by a single base-pair deletion at the 194th nucleotide position generate two stop codons, truncating almost the entire C-terminal, which is important for effector function and R4 recognition in all sequences. The effector is under natural selection for adaptation supported by comparative analyses of population differentiation (FST ) and isolation-by-distance between Avr4 sequences and simple sequence repeat marker loci. Furthermore, we found that local air temperature was positively associated with pairwise FST in the Avr4 sequences. These results suggest that the evolution of the effector gene is influenced by local air temperature, and the C-terminal truncation is one of the main mutation mechanisms in the P. infestans effector gene to circumvent the immune response of potato plants. The implication of these results to agricultural and natural sustainability in future climate conditions is discussed.
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Affiliation(s)
- Abdul Waheed
- Key Lab for Bio Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yan-Ping Wang
- Key Lab for Bio Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Oswald Nkurikiyimfura
- Key Lab for Bio Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wen-Yang Li
- Key Lab for Bio Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shi-Ting Liu
- Key Lab for Bio Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yahuza Lurwanu
- Key Lab for Bio Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
- Department of Crop Protection, Bayero University Kano, Kano, Nigeria
| | - Guo-Dong Lu
- Key Lab for Bio Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zong-Hua Wang
- Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Institute of Oceanography, Minjiang University, Fuzhou, China
| | - Li-Na Yang
- Key Lab for Bio Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
- Institute of Oceanography, Minjiang University, Fuzhou, China
| | - Jiasui Zhan
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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15
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Das M, Kantz H. Role of thermal fluctuations in biological copying mechanisms. Phys Rev E 2021; 103:032110. [PMID: 33862776 DOI: 10.1103/physreve.103.032110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 02/18/2021] [Indexed: 11/07/2022]
Abstract
During transcription, translation, or self-replication of DNA or RNA, information is transferred to the newly formed species from its predecessor. These processes can be interpreted as (generalized) biological copying mechanism as the new biological entities like DNA, RNA, or proteins are representing the information of their parent bodies uniquely. The accuracy of these copying processes is essential, since errors in the copied code can reduce the functionality of the next generation. Such errors might result from perturbations on these processes. Most important in this context is the temperature of the medium, i.e., thermal noise. Although a reasonable amount of experimental studies have been carried out on this important issue, theoretical understanding is truly sparse. In the present work, we illustrate a model study which is able to focus on the effect of the temperature on the process of biological copying mechanisms, as well as on mutation. We find for our paradigmatic models that, in a quite general scenario, the copying processes are most accurate at an intermediate temperature range; i.e., there exists an optimum temperature where mutation is most unlikely. This allows us to interpret the observations for some biological species with the aid of our model study.
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Affiliation(s)
- Moupriya Das
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - Holger Kantz
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
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16
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Berger D, Stångberg J, Baur J, Walters RJ. Elevated temperature increases genome-wide selection on de novo mutations. Proc Biol Sci 2021; 288:20203094. [PMID: 33529558 DOI: 10.1098/rspb.2020.3094] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Adaptation in new environments depends on the amount of genetic variation available for evolution, and the efficacy by which natural selection discriminates among this variation. However, whether some ecological factors reveal more genetic variation, or impose stronger selection pressures than others, is typically not known. Here, we apply the enzyme kinetic theory to show that rising global temperatures are predicted to intensify natural selection throughout the genome by increasing the effects of DNA sequence variation on protein stability. We test this prediction by (i) estimating temperature-dependent fitness effects of induced mutations in seed beetles adapted to ancestral or elevated temperature, and (ii) calculate 100 paired selection estimates on mutations in benign versus stressful environments from unicellular and multicellular organisms. Environmental stress per se did not increase mean selection on de novo mutation, suggesting that the cost of adaptation does not generally increase in new ecological settings to which the organism is maladapted. However, elevated temperature increased the mean strength of selection on genome-wide polymorphism, signified by increases in both mutation load and mutational variance in fitness. These results have important implications for genetic diversity gradients and the rate and repeatability of evolution under climate change.
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Affiliation(s)
- David Berger
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Josefine Stångberg
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Julian Baur
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Richard J Walters
- Centre for Environmental and Climate Research, Lund University, Sölvegatan 37, 223 62 Lund, Sweden
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17
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Experimental evidence for effects of sexual selection on condition-dependent mutation rates. Nat Ecol Evol 2020; 4:737-744. [DOI: 10.1038/s41559-020-1140-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 02/10/2020] [Indexed: 01/13/2023]
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18
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Affiliation(s)
- Matthias Galipaud
- Department of evolutionary biology and environmental studies University of Zurich Zurich Switzerland
| | - Hanna Kokko
- Department of evolutionary biology and environmental studies University of Zurich Zurich Switzerland
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19
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The Role of Mutation Bias in Adaptive Evolution. Trends Ecol Evol 2019; 34:422-434. [PMID: 31003616 DOI: 10.1016/j.tree.2019.01.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/27/2019] [Accepted: 01/30/2019] [Indexed: 11/24/2022]
Abstract
Mutational input is the ultimate source of genetic variation, but mutations are not thought to affect the direction of adaptive evolution. Recently, critics of standard evolutionary theory have questioned the random and non-directional nature of mutations, claiming that the mutational process can be adaptive in its own right. We discuss here mutation bias in adaptive evolution. We find little support for mutation bias as an independent force in adaptive evolution, although it can interact with selection under conditions of small population size and when standing genetic variation is limited, entirely consistent with standard evolutionary theory. We further emphasize that natural selection can shape the phenotypic effects of mutations, giving the false impression that directed mutations are driving adaptive evolution.
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20
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Romero-Mujalli D, Jeltsch F, Tiedemann R. Elevated mutation rates are unlikely to evolve in sexual species, not even under rapid environmental change. BMC Evol Biol 2019; 19:175. [PMID: 31462290 PMCID: PMC6714099 DOI: 10.1186/s12862-019-1494-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 08/06/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Organisms are expected to respond to changing environmental conditions through local adaptation, range shift or local extinction. The process of local adaptation can occur by genetic changes or phenotypic plasticity, and becomes especially relevant when dispersal abilities or possibilities are somehow constrained. For genetic changes to occur, mutations are the ultimate source of variation and the mutation rate in terms of a mutator locus can be subject to evolutionary change. Recent findings suggest that the evolution of the mutation rate in a sexual species can advance invasion speed and promote adaptation to novel environmental conditions. Following this idea, this work uses an individual-based model approach to investigate if the mutation rate can also evolve in a sexual species experiencing different conditions of directional climate change, under different scenarios of colored stochastic environmental noise, probability of recombination and of beneficial mutations. The color of the noise mimicked investigating the evolutionary dynamics of the mutation rate in different habitats. RESULTS The results suggest that the mutation rate in a sexual species experiencing directional climate change scenarios can evolve and reach relatively high values mainly under conditions of complete linkage of the mutator locus and the adaptation locus. In contrast, when they are unlinked, the mutation rate can slightly increase only under scenarios where at least 50% of arising mutations are beneficial and the rate of environmental change is relatively fast. This result is robust under different scenarios of stochastic environmental noise, which supports the observation of no systematic variation in the mutation rate among organisms experiencing different habitats. CONCLUSIONS Given that 50% beneficial mutations may be an unrealistic assumption, and that recombination is ubiquitous in sexual species, the evolution of an elevated mutation rate in a sexual species experiencing directional climate change might be rather unlikely. Furthermore, when the percentage of beneficial mutations and the population size are small, sexual species (especially multicellular ones) producing few offspring may be expected to react to changing environments not by adaptive genetic change, but mainly through plasticity. Without the ability for a plastic response, such species may become - at least locally - extinct.
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Affiliation(s)
- Daniel Romero-Mujalli
- University of Potsdam, Evolutionary Biology/Systematic Zoology, Karl-Liebknecht-Strasse 24-25, 14476, Potsdam, Germany. .,Plant Ecology and Nature Conservation, University of Potsdam, Am Mühlenberg 3, 14476, Potsdam, Germany.
| | - Florian Jeltsch
- Plant Ecology and Nature Conservation, University of Potsdam, Am Mühlenberg 3, 14476, Potsdam, Germany.,Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), 14195, Berlin, Germany
| | - Ralph Tiedemann
- University of Potsdam, Evolutionary Biology/Systematic Zoology, Karl-Liebknecht-Strasse 24-25, 14476, Potsdam, Germany
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21
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Baur J, Nsanzimana JD, Berger D. Sexual selection and the evolution of male and female cognition: A test using experimental evolution in seed beetles. Evolution 2019; 73:2390-2400. [PMID: 31273775 DOI: 10.1111/evo.13793] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/20/2019] [Indexed: 01/03/2023]
Abstract
The mating system is thought to be important in shaping animal intelligence and sexual selection has been depicted as a driver of cognitive evolution, either directly by promoting superior cognitive ability during mate competition, or indirectly via genic capture of sexually selected traits. However, it remains unclear if intensified sexual selection leads to general improvements in cognitive abilities. Here, we evaluated this hypothesis by applying experimental evolution in seed beetles. Replicate lines, maintained for 35 generations of either enforced monogamy (eliminating sexual selection) or polygamy, were challenged to locate and discriminate among mates (male assays) or host seeds (female assays) in a spatial chemosensory learning task. All lines displayed learning between trials. Moreover, polygamous males outperformed monogamous males, providing evidence that sexual selection can lead to the evolution of improved male cognition. However, there were no differences between regimes in rates of male learning, and polygamous females showed no improvement in host search and even signs of reduced learning. Hence, sexual selection increased performance in cognitively demanding mate search, but it did not lead to general increases in cognitive abilities. We discuss the possibility that sexually antagonistic selection is an important factor maintaining abundant genetic variation in cognitive traits.
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Affiliation(s)
- Julian Baur
- Department of Ecology and Genetics, Animal Ecology program, Uppsala University, Uppsala, Sweden
| | - Jean d'Amour Nsanzimana
- Department of Ecology and Genetics, Animal Ecology program, Uppsala University, Uppsala, Sweden
| | - David Berger
- Department of Ecology and Genetics, Animal Ecology program, Uppsala University, Uppsala, Sweden
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22
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Lind MI, Ravindran S, Sekajova Z, Carlsson H, Hinas A, Maklakov AA. Experimentally reduced insulin/IGF-1 signaling in adulthood extends lifespan of parents and improves Darwinian fitness of their offspring. Evol Lett 2019; 3:207-216. [PMID: 31007945 PMCID: PMC6457396 DOI: 10.1002/evl3.108] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/06/2019] [Indexed: 11/29/2022] Open
Abstract
Classical theory maintains that ageing evolves via energy trade-offs between reproduction and survival leading to accumulation of unrepaired cellular damage with age. In contrast, the emerging new theory postulates that ageing evolves because of deleterious late-life hyper-function of reproduction-promoting genes leading to excessive biosynthesis in late-life. The hyper-function theory uniquely predicts that optimizing nutrient-sensing molecular signaling in adulthood can simultaneously postpone ageing and increase Darwinian fitness. Here, we show that reducing evolutionarily conserved insulin/IGF-1 nutrient-sensing signaling via daf-2 RNA interference (RNAi) fulfils this prediction in Caenorhabditis elegans nematodes. Long-lived daf-2 RNAi parents showed normal fecundity as self-fertilizing hermaphrodites and improved late-life reproduction when mated to males. Remarkably, the offspring of daf-2 RNAi parents had higher Darwinian fitness across three different genotypes. Thus, reduced nutrient-sensing signaling in adulthood improves both parental longevity and offspring fitness supporting the emerging view that suboptimal gene expression in late-life lies at the heart of ageing.
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Affiliation(s)
- Martin I. Lind
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsala752 36Sweden
| | - Sanjana Ravindran
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsala752 36Sweden
| | - Zuzana Sekajova
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsala752 36Sweden
| | - Hanne Carlsson
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsala752 36Sweden
- School of Biological SciencesUniversity of East AngliaNorwichNR4 7TJUnited Kingdom
| | - Andrea Hinas
- Department of Cell and Molecular BiologyUppsala UniversityUppsala751 24Sweden
| | - Alexei A. Maklakov
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsala752 36Sweden
- School of Biological SciencesUniversity of East AngliaNorwichNR4 7TJUnited Kingdom
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23
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Corkrey R, Macdonald C, McMeekin T. The Biokinetic Spectrum for Temperature and optimal Darwinian fitness. J Theor Biol 2019; 462:171-183. [PMID: 30385312 DOI: 10.1016/j.jtbi.2018.10.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 10/26/2018] [Accepted: 10/29/2018] [Indexed: 10/28/2022]
Abstract
Darwinian fitness is maximised at a temperature below Topt, but what this temperature is remains unclear. By linking our previous work on the Biokinetic Spectrum for Temperature with a model for temperature-dependent biological growth rate we obtain a plausible value for such a temperature. We find this approach reveals considerable commonalities in how life responds to temperature with implications that follow in evolution, physiology and ecology. We described a data set consisting of 17,021 observations of temperature-dependent population growth rates from 2411 bacterial, archaeal and eukaryal strains. We fitted a thermodynamic model to describe the strains' temperature-dependent growth rate curves that assumed growth was limited by a single rate-limiting enzyme. We defined Umes as an empirical measure of the temperature at which strains grew as fast and also as efficiently as possible. We propose that Darwinian fitness is optimised at Umes by trading-off growth rate and physiological efficiency. Using the full data set we calculated the Biokinetic Spectrum for Temperature (BKST): the distribution of temperature-dependent growth rates for each temperature. We used quantile regression to fit alternative models to the BKST to obtain quantile curves. A quantile is a value that contains a particular proportion of the data. The quantile curves suggested commonalities in temperature-dependencies spanning taxa and ecotype, consistent with the single rate-limiting enzyme concept. We showed that on the log scale, the slopes of the quantile curves were the same as the slopes of the thermodynamic model growth curves at Umes. This was true for Bacteria, Archaea, and Eukarya, and across other conditions (pH, water activity, metabolic type and trophic type). We showed that the quantile curves were the loci of the temperatures and growth rates that optimised Darwinian fitness for each strain at a given temperature-dependence and independently of other conditions. The quantile curves for Archaea and Bacteria shared a number of similarities attributable to the influence of the properties of water on protein folding. Other implications have impact on evolutionary biology, ecology, and physiology. The model predicts the existence of eurythermic strains that grow with about equal efficiency over a broad temperature range. These strains will have higher evolutionary rates with lower mutational costs that are independent of environmental conditions, a factor likely to have been significant during the Precambrian if the early Earth was warmer than today. The model predicts that random mutations are likely to result in shifts along the quantile curves and not across them. It predicts that some psychrophiles will be capable of performing well under climate change, and that selection will favour faster growth rates as the temperature increases. Last, it predicts trade-offs between growth rate and soma production, so that temperature-dependence, and possibly Darwinian fitness, remain constant over a broad temperature range and growth rates.
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Affiliation(s)
- Ross Corkrey
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia.
| | - Cameron Macdonald
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
| | - Tom McMeekin
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
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24
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Berger D, Stångberg J, Grieshop K, Martinossi-Allibert I, Arnqvist G. Temperature effects on life-history trade-offs, germline maintenance and mutation rate under simulated climate warming. Proc Biol Sci 2018; 284:rspb.2017.1721. [PMID: 29118134 DOI: 10.1098/rspb.2017.1721] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/06/2017] [Indexed: 01/28/2023] Open
Abstract
Mutation has a fundamental influence over evolutionary processes, but how evolutionary processes shape mutation rate remains less clear. In asexual unicellular organism, increased mutation rates have been observed in stressful environments and the reigning paradigm ascribes this increase to selection for evolvability. However, this explanation does not apply in sexually reproducing species, where little is known about how the environment affects mutation rate. Here we challenged experimental lines of seed beetle, evolved at ancestral temperature or under simulated climate warming, to repair induced mutations at ancestral and stressful temperature. Results show that temperature stress causes individuals to pass on a greater mutation load to their grand-offspring. This suggests that stress-induced mutation rates, in unicellular and multicellular organisms alike, can result from compromised germline DNA repair in low condition individuals. Moreover, lines adapted to simulated climate warming had evolved increased longevity at the cost of reproduction, and this allocation decision improved germline repair. These results suggest that mutation rates can be modulated by resource allocation trade-offs encompassing life-history traits and the germline and have important implications for rates of adaptation and extinction as well as our understanding of genetic diversity in multicellular organisms.
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Affiliation(s)
- David Berger
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala, Sweden
| | - Josefine Stångberg
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala, Sweden
| | - Karl Grieshop
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala, Sweden
| | | | - Göran Arnqvist
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala, Sweden
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