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Péron G. The effect of the demographic history on the evolution of senescence: A potential new test of the mutation accumulation theory. Mech Ageing Dev 2024; 219:111927. [PMID: 38499252 DOI: 10.1016/j.mad.2024.111927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/26/2024] [Accepted: 03/12/2024] [Indexed: 03/20/2024]
Abstract
The different evolutionary theories of senescence predict different directions for the correlation between the population size and the intensity of senescence. Using simulations, I highlighted how the effect of the population size on the intensity of senescence could be reinforced by the time since populations have been large or small. I devised a mutation-selection model in which the effect of the mutations was age-specific. Several small populations diverged from a same large population at different points in time. At the end of the simulation, the correlation between the time since the populations had been small and the rate of senescence was positive under the mutation accumulation theory and negative under the antagonistic pleiotropy theory. The phenomenon was strong enough to reverse the usually negative relationship between the intensity of senescence and the generation time. These mutually-exclusive predictions could help broaden the taxonomic support for the mutation accumulation theory of senescence, currently mostly supported in humans and lab invertebrates. I briefly mention a few potential applications in real-life systems.
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Affiliation(s)
- Guillaume Péron
- CNRS, Université Lyon 1, 43 bd du 11 novembre 1918, VILLEURBANNE cedex 69622, France.
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2
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Ellis S, Franks DW, Nielsen MLK, Weiss MN, Croft DP. The evolution of menopause in toothed whales. Nature 2024; 627:579-585. [PMID: 38480878 PMCID: PMC10954554 DOI: 10.1038/s41586-024-07159-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 02/05/2024] [Indexed: 03/20/2024]
Abstract
Understanding how and why menopause has evolved is a long-standing challenge across disciplines. Females can typically maximize their reproductive success by reproducing for the whole of their adult life. In humans, however, women cease reproduction several decades before the end of their natural lifespan1,2. Although progress has been made in understanding the adaptive value of menopause in humans3,4, the generality of these findings remains unclear. Toothed whales are the only mammal taxon in which menopause has evolved several times5, providing a unique opportunity to test the theories of how and why menopause evolves in a comparative context. Here, we assemble and analyse a comparative database to test competing evolutionary hypotheses. We find that menopause evolved in toothed whales by females extending their lifespan without increasing their reproductive lifespan, as predicted by the 'live-long' hypotheses. We further show that menopause results in females increasing their opportunity for intergenerational help by increasing their lifespan overlap with their grandoffspring and offspring without increasing their reproductive overlap with their daughters. Our results provide an informative comparison for the evolution of human life history and demonstrate that the same pathway that led to menopause in humans can also explain the evolution of menopause in toothed whales.
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Affiliation(s)
- Samuel Ellis
- Centre for Research in Animal Behaviour, Department of Psychology, University of Exeter, Exeter, UK.
| | | | | | - Michael N Weiss
- Centre for Research in Animal Behaviour, Department of Psychology, University of Exeter, Exeter, UK
- Center for Whale Research, Friday Harbor, WA, USA
| | - Darren P Croft
- Centre for Research in Animal Behaviour, Department of Psychology, University of Exeter, Exeter, UK
- Center for Whale Research, Friday Harbor, WA, USA
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3
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Lemaître JF, Moorad J, Gaillard JM, Maklakov AA, Nussey DH. A unified framework for evolutionary genetic and physiological theories of aging. PLoS Biol 2024; 22:e3002513. [PMID: 38412150 PMCID: PMC10898761 DOI: 10.1371/journal.pbio.3002513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024] Open
Abstract
Why and how we age are 2 intertwined questions that have fascinated scientists for many decades. However, attempts to answer these questions remain compartmentalized, preventing a comprehensive understanding of the aging process. We argue that the current lack of knowledge about the evolution of aging mechanisms is due to a lack of clarity regarding evolutionary theories of aging that explicitly involve physiological processes: the disposable soma theory (DST) and the developmental theory of aging (DTA). In this Essay, we propose a new hierarchical model linking genes to vital rates, enabling us to critically reevaluate the DST and DTA in terms of their relationship to evolutionary genetic theories of aging (mutation accumulation (MA) and antagonistic pleiotropy (AP)). We also demonstrate how these 2 theories can be incorporated in a unified hierarchical framework. The new framework will help to generate testable hypotheses of how the hallmarks of aging are shaped by natural selection.
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Affiliation(s)
- Jean-François Lemaître
- Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR 5558, Villeurbanne, France
| | - Jacob Moorad
- Institute of Ecology & Evolution, School of Biological Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Jean-Michel Gaillard
- Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR 5558, Villeurbanne, France
| | - Alexei A. Maklakov
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Daniel H. Nussey
- Institute of Ecology & Evolution, School of Biological Science, University of Edinburgh, Edinburgh, United Kingdom
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4
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Sanghvi K, Vega-Trejo R, Nakagawa S, Gascoigne SJL, Johnson SL, Salguero-Gómez R, Pizzari T, Sepil I. Meta-analysis shows no consistent evidence for senescence in ejaculate traits across animals. Nat Commun 2024; 15:558. [PMID: 38228708 PMCID: PMC10791739 DOI: 10.1038/s41467-024-44768-4] [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: 07/13/2023] [Accepted: 01/04/2024] [Indexed: 01/18/2024] Open
Abstract
Male reproductive traits such as ejaculate size and quality, are expected to decline with advancing age due to senescence. It is however unclear whether this expectation is upheld across taxa. We perform a meta-analysis on 379 studies, to quantify the effects of advancing male age on ejaculate traits across 157 species of non-human animals. Contrary to predictions, we find no consistent pattern of age-dependent changes in ejaculate traits. This result partly reflects methodological limitations, such as studies sampling a low proportion of adult lifespan, or the inability of meta-analytical approaches to document non-linear ageing trajectories of ejaculate traits; which could potentially lead to an underestimation of senescence. Yet, we find taxon-specific differences in patterns of ejaculate senescence. For instance, older males produce less motile and slower sperm in ray-finned fishes, but larger ejaculates in insects, compared to younger males. Notably, lab rodents show senescence in most ejaculate traits measured. Our study challenges the notion of universal reproductive senescence, highlighting the need for controlled methodologies and a more nuanced understanding of reproductive senescence, cognisant of taxon-specific biology, experimental design, selection pressures, and life-history.
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Affiliation(s)
- Krish Sanghvi
- Department of Biology, University of Oxford, Oxford, UK.
| | | | - Shinichi Nakagawa
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
| | | | - Sheri L Johnson
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | | | | | - Irem Sepil
- Department of Biology, University of Oxford, Oxford, UK.
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Yang M, Harrison BR, Promislow DEL. Cellular age explains variation in age-related cell-to-cell transcriptome variability. Genome Res 2023; 33:gr.278144.123. [PMID: 37973195 PMCID: PMC10760448 DOI: 10.1101/gr.278144.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/12/2023] [Indexed: 11/19/2023]
Abstract
Organs and tissues age at different rates within a single individual. Such asynchrony in aging has been widely observed at multiple levels, from functional hallmarks, such as anatomical structures and physiological processes, to molecular endophenotypes, such as the transcriptome and metabolome. However, we lack a conceptual framework to understand why some components age faster than others. Just as demographic models explain why aging evolves, here we test the hypothesis that demographic differences among cell types, determined by cell-specific differences in turnover rate, can explain why the transcriptome shows signs of aging in some cell types but not others. Through analysis of mouse single-cell transcriptome data across diverse tissues and ages, we find that cellular age explains a large proportion of the variation in the age-related increase in transcriptome variance. We further show that long-lived cells are characterized by relatively high expression of genes associated with proteostasis and that the transcriptome of long-lived cells shows greater evolutionary constraint than short-lived cells. In contrast, in short-lived cell types, the transcriptome is enriched for genes associated with DNA repair. Based on these observations, we develop a novel heuristic model that explains how and why aging rates differ among cell types.
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Affiliation(s)
- Ming Yang
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington 98195, USA
| | - Benjamin R Harrison
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington 98195, USA
| | - Daniel E L Promislow
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington 98195, USA;
- Department of Biology, University of Washington, Seattle, Washington 98195, USA
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6
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Tangili M, Slettenhaar AJ, Sudyka J, Dugdale HL, Pen I, Palsbøll PJ, Verhulst S. DNA methylation markers of age(ing) in non-model animals. Mol Ecol 2023; 32:4725-4741. [PMID: 37401200 DOI: 10.1111/mec.17065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/05/2023]
Abstract
Inferring the chronological and biological age of individuals is fundamental to population ecology and our understanding of ageing itself, its evolution, and the biological processes that affect or even cause ageing. Epigenetic clocks based on DNA methylation (DNAm) at specific CpG sites show a strong correlation with chronological age in humans, and discrepancies between inferred and actual chronological age predict morbidity and mortality. Recently, a growing number of epigenetic clocks have been developed in non-model animals and we here review these studies. We also conduct a meta-analysis to assess the effects of different aspects of experimental protocol on the performance of epigenetic clocks for non-model animals. Two measures of performance are usually reported, the R2 of the association between the predicted and chronological age, and the mean/median absolute deviation (MAD) of estimated age from chronological age, and we argue that only the MAD reflects accuracy. R2 for epigenetic clocks based on the HorvathMammalMethylChip4 was higher and the MAD scaled to age range lower, compared with other DNAm quantification approaches. Scaled MAD tended to be lower among individuals in captive populations, and decreased with an increasing number of CpG sites. We conclude that epigenetic clocks can predict chronological age with relatively high accuracy, suggesting great potential in ecological epigenetics. We discuss general aspects of epigenetic clocks in the hope of stimulating further DNAm-based research on ageing, and perhaps more importantly, other key traits.
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Affiliation(s)
- Marianthi Tangili
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Annabel J Slettenhaar
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Joanna Sudyka
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Hannah L Dugdale
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
- Faculty of Biological Sciences, School of Biology, University of Leeds, Leeds, UK
| | - Ido Pen
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Per J Palsbøll
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
- Center for Coastal Studies, Provincetown, Massachusetts, USA
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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