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Brown LM, Elbon MC, Bharadwaj A, Damle G, Lachance J. Does Effective Population Size Govern Evolutionary Differences in Telomere Length? Genome Biol Evol 2024; 16:evae111. [PMID: 38771124 PMCID: PMC11140418 DOI: 10.1093/gbe/evae111] [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: 08/28/2023] [Revised: 05/08/2024] [Accepted: 05/14/2024] [Indexed: 05/22/2024] Open
Abstract
Lengths of telomeres vary by an order of magnitude across mammalian species. Similarly, age- and sex-standardized telomere lengths differ by up to 1 kb (14%) across human populations. How to explain these differences? Telomeres play a central role in senescence and aging, and genes that affect telomere length are likely under weak selection (i.e. telomere length is a trait that is subject to nearly neutral evolution). Importantly, natural selection is more effective in large populations than in small populations. Here, we propose that observed differences in telomere length across species and populations are largely due to differences in effective population sizes. In this perspective, we present preliminary evolutionary genetic evidence supporting this hypothesis and highlight the need for more data.
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Affiliation(s)
- Lyda M Brown
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Mia C Elbon
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Ajay Bharadwaj
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Gargi Damle
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Joseph Lachance
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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2
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Pepke ML. Telomere length is not a useful tool for chronological age estimation in animals. Bioessays 2024; 46:e2300187. [PMID: 38047504 DOI: 10.1002/bies.202300187] [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: 09/27/2023] [Revised: 11/16/2023] [Accepted: 11/20/2023] [Indexed: 12/05/2023]
Abstract
Telomeres are short repetitive DNA sequences capping the ends of chromosomes. Telomere shortening occurs during cell division and may be accelerated by oxidative damage or ameliorated by telomere maintenance mechanisms. Consequently, telomere length changes with age, which was recently confirmed in a large meta-analysis across vertebrates. However, based on the correlation between telomere length and age, it was concluded that telomere length can be used as a tool for chronological age estimation in animals. Correlation should not be confused with predictability, and the current data and studies suggest that telomeres cannot be used to reliably predict individual chronological age. There are biological reasons for why there is large individual variation in telomere dynamics, which is mainly due to high susceptibility to a wide range of environmental, but also genetic factors, rendering telomeres unfeasible as a tool for age estimation. The use of telomeres for chronological age estimation is largely a misguided effort, but its occasional reappearance in the literature raises concerns that it will mislead resources in wildlife conservation.
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Affiliation(s)
- Michael L Pepke
- Center for Evolutionary Hologenomics, Globe Institute, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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3
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Atema E, van Noordwijk AJ, Verhulst S. Telomere dynamics in relation to experimentally increased locomotion costs and fitness in great tits. Mol Ecol 2022; 31:6208-6215. [PMID: 34478576 PMCID: PMC9786264 DOI: 10.1111/mec.16162] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 08/06/2021] [Accepted: 08/20/2021] [Indexed: 02/02/2023]
Abstract
Evidence that telomere length (TL) and dynamics can be interpreted as proxy for 'life stress' experienced by individuals stems largely from correlational studies. We tested for effects of an experimental increase of workload on telomere dynamics by equipping male great tits (Parus major) with a 0.9 g backpack for a full year. In addition, we analysed associations between natural life-history variation, TL and TL dynamics. Carrying 5% extra weight for a year did not significantly accelerate telomere attrition. This agrees with our earlier finding that this experiment did not affect survival or future reproduction. Apparently, great tit males were able to compensate behaviourally or physiologically for the increase in locomotion costs we imposed. We found no cross-sectional association between reproductive success and TL, but individuals with higher reproductive success (number of recruits) lost fewer telomere base pairs in the subsequent year. We used the TRF method to measure TL, which method yields a TL distribution for each sample, and the association between reproductive success and telomere loss was more pronounced in the higher percentiles of the telomere distribution, in agreement with the higher impact of ageing on longer telomeres within individuals. Individuals with longer telomeres and less telomere shortening were more likely to survive to the next breeding season, but these patterns did not reach statistical significance. Whether successful individuals are characterized by losing fewer or more base pairs from their telomeres varies between species, and we discuss aspects of ecology and social organisation that may explain this variation.
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Affiliation(s)
- Els Atema
- GELIFESUniversity of GroningenGroningenthe Netherlands,Netherlands Institute of EcologyWageningenthe Netherlands
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4
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Boonekamp J, Rodríguez-Muñoz R, Hopwood P, Zuidersma E, Mulder E, Wilson A, Verhulst S, Tregenza T. Telomere length is highly heritable and independent of growth rate manipulated by temperature in field crickets. Mol Ecol 2022; 31:6128-6140. [PMID: 33728719 DOI: 10.1111/mec.15888] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 01/31/2023]
Abstract
Many organisms are capable of growing faster than they do. Restrained growth rate has functionally been explained by negative effects on lifespan of accelerated growth. However, the underlying mechanisms remain elusive. Telomere attrition has been proposed as a causal agent and has been mostly studied in endothermic vertebrates. We established that telomeres exist as chromosomal-ends in a model insect, the field cricket Gryllus campestris, using terminal restriction fragment and Bal 31 methods. Telomeres comprised TTAGGn repeats of 38 kb on average, more than four times longer than the telomeres of human infants. Bal 31 assays confirmed that telomeric repeats were located at the chromosome-ends. We tested whether rapid growth between day 1, day 65, day 85, and day 125 is achieved at the expense of telomere length by comparing nymphs reared at 23°C with their siblings reared at 28°C, which grew three times faster in the initial 65 days. Surprisingly, neither temperature treatment nor age affected average telomere length. Concomitantly, the broad sense heritability of telomere length was remarkably high at ~100%. Despite high heritability, the evolvability (a mean-standardized measure of genetic variance) was low relative to that of body mass. We discuss our findings in the context of telomere evolution. Some important features of vertebrate telomere biology are evident in an insect species dating back to the Triassic. The apparent lack of an effect of growth rate on telomere length is puzzling, suggesting strong telomere length maintenance during the growth phase. Whether such maintenance of telomere length is adaptive remains elusive and requires further study investigating the links with fitness in the wild.
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Affiliation(s)
- Jelle Boonekamp
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Exeter, UK.,Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | | | - Paul Hopwood
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Exeter, UK
| | - Erica Zuidersma
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Ellis Mulder
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Alastair Wilson
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Exeter, UK
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Tom Tregenza
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Exeter, UK
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5
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Salmón P, Burraco P. Telomeres and anthropogenic disturbances in wildlife: A systematic review and meta-analysis. Mol Ecol 2022; 31:6018-6039. [PMID: 35080073 PMCID: PMC9790527 DOI: 10.1111/mec.16370] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 12/10/2021] [Accepted: 01/13/2022] [Indexed: 01/31/2023]
Abstract
Human-driven environmental changes are affecting wildlife across the globe. These challenges do not influence species or populations to the same extent and therefore a comprehensive evaluation of organismal health is needed to determine their ultimate impact. Evidence suggests that telomeres (the terminal chromosomal regions) are sensitive to environmental conditions and have been posited as a surrogate for animal health and fitness. Evaluation of their use in an applied ecological context is still scarce. Here, using information from molecular and occupational biomedical studies, we aim to provide ecologists and evolutionary biologists with an accessible synthesis of the links between human disturbances and telomere length. In addition, we perform a systematic review and meta-analysis on studies measuring telomere length in wild/wild-derived animals facing anthropogenic disturbances. Despite the relatively small number of studies to date, our meta-analysis revealed a significant small negative association between disturbances and telomere length (-0.092 [-0.153, -0.031]; n = 28; k = 159). Yet, our systematic review suggests that the use of telomeres as a biomarker to understand the anthropogenic impact on wildlife is limited. We propose some research avenues that will help to broadly evaluate their suitability: (i) further causal studies on the link between human disturbances and telomeres; (ii) investigating the organismal implications, in terms of fitness and performance, of a given telomere length in anthropogenically disturbed scenarios; and (iii) better understanding of the underlying mechanisms of telomere dynamics. Future studies in these facets will help to ultimately determine their role as markers of health and fitness in wildlife facing anthropogenic disturbances.
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Affiliation(s)
- Pablo Salmón
- Institute of Biodiversity, Animal Health and Comparative MedicineUniversity of GlasgowGlasgowUK,Department of Plant Biology and EcologyFaculty of Science and TechnologyUniversity of the Basque Country (UPV/EHU)LeioaSpain
| | - Pablo Burraco
- Institute of Biodiversity, Animal Health and Comparative MedicineUniversity of GlasgowGlasgowUK
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6
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Bauch C, Boonekamp JJ, Korsten P, Mulder E, Verhulst S. High heritability of telomere length and low heritability of telomere shortening in wild birds. Mol Ecol 2022; 31:6308-6323. [PMID: 34532917 PMCID: PMC9787985 DOI: 10.1111/mec.16183] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 08/06/2021] [Accepted: 09/08/2021] [Indexed: 01/31/2023]
Abstract
Telomere length and telomere shortening predict survival in many organisms. This raises the question of the contribution of genetic and environmental effects to variation in these traits, which is still poorly known, particularly for telomere shortening. We used experimental (cross-fostering) and statistical (quantitative genetic "animal models") means to disentangle and estimate genetic and environmental contributions to telomere length variation in pedigreed free-living jackdaws (Corvus monedula). Telomere length was measured twice in nestlings, at ages 4 (n = 715) and 29 days (n = 474), using telomere restriction fragment (TRF) analysis, adapted to exclude interstitial telomeric sequences. Telomere length shortened significantly over the nestling period (10.4 ± 0.3 bp day-1 ) and was highly phenotypically (rP = 0.95 ± 0.01) and genetically (rG > 0.99 ± 0.01) correlated within individuals. Additive genetic effects explained a major part of telomere length variation among individuals, with its heritability estimated at h2 = 0.74 on average. We note that TRF-based studies reported higher heritabilities than qPCR-based studies, and we discuss possible explanations. Parent-offspring regressions yielded similar heritability estimates for mothers and fathers when accounting for changes in paternal telomere length over life. Year effects explained a small but significant part of telomere length variation. Heritable variation for telomere shortening was low (h2 = 0.09 ± 0.11). The difference in heritability between telomere length (high) and telomere shortening (low) agrees with evolutionary theory, in that telomere shortening has stronger fitness consequences in this population. Despite the high heritability of telomere length, its evolvability, which scales the additive genetic variance by mean telomere length, was on average 0.48%. Hence, evolutionary change of telomere length due to selection is likely to be slow.
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Affiliation(s)
- Christina Bauch
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Jelle J. Boonekamp
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands,Present address:
Institute of Biodiversity Animal Health & Comparative MedicineCollege of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Peter Korsten
- Department of Animal BehaviourBielefeld UniversityBielefeldGermany
| | - Ellis Mulder
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
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7
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Kärkkäinen T, Briga M, Laaksonen T, Stier A. Within-individual repeatability in telomere length: A meta-analysis in nonmammalian vertebrates. Mol Ecol 2022; 31:6339-6359. [PMID: 34455645 DOI: 10.1111/mec.16155] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 07/27/2021] [Accepted: 08/23/2021] [Indexed: 01/31/2023]
Abstract
Telomere length is increasingly used as a biomarker of long-term somatic state and future survival prospects. While most studies have overlooked this aspect, biological interpretations based on a given telomere length will benefit from considering the level of within-individual repeatability of telomere length through time. Therefore, we conducted a meta-analysis on 74 longitudinal studies in nonmammalian vertebrates, with the aim to establish the current pattern of within-individual repeatability in telomere length and to identify the methodological (e.g., qPCR/TRF) and biological factors (e.g., age class, phylogeny) that may affect it. While the median within-individual repeatability of telomere length was moderate to high (R = 0.55; 95% CI: 0.05-0.95; N = 82), marked heterogeneity between studies was evident. Measurement method affected the repeatability estimate strongly, with TRF-based studies exhibiting high repeatability (R = 0.80; 95% CI: 0.34-0.96; N = 25), while repeatability of qPCR-based studies was markedly lower and more variable (R = 0.46; 95% CI: 0.04-0.82; N = 57). While phylogeny explained some variance in repeatability, phylogenetic signal was not significant (λ = 0.32; 95% CI: 0.00-0.83). None of the biological factors investigated here significantly explained variation in the repeatability of telomere length, being potentially obscured by methodological differences. Our meta-analysis highlights the high variability in within-individual repeatability estimates between studies and the need to put more effort into separating technical and biological explanations. This is important to better understand to what extent biological factors can affect the repeatability of telomere length and thus the interpretation of telomere length data.
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Affiliation(s)
| | - Michael Briga
- Department of Biology, University of Turku, Turku, Finland
| | - Toni Laaksonen
- Department of Biology, University of Turku, Turku, Finland
| | - Antoine Stier
- Department of Biology, University of Turku, Turku, Finland
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8
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Romero-Haro AÁ, Morger J, Haussmann MF, Tschirren B. Reproductive strategies affect telomere dynamics across the life course. Am Nat 2022; 200:373-382. [DOI: 10.1086/720440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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9
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Andrews C, Zuidersma E, Verhulst S, Nettle D, Bateson M. Exposure to food insecurity increases energy storage and reduces somatic maintenance in European starlings ( Sturnus vulgaris). ROYAL SOCIETY OPEN SCIENCE 2021; 8:211099. [PMID: 34540262 PMCID: PMC8441118 DOI: 10.1098/rsos.211099] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/24/2021] [Indexed: 05/11/2023]
Abstract
Birds exposed to food insecurity-defined as temporally variable access to food-respond adaptively by storing more energy. To do this, they may reduce energy allocation to other functions such as somatic maintenance and repair. To investigate this trade-off, we exposed juvenile European starlings (Sturnus vulgaris, n = 69) to 19 weeks of either uninterrupted food availability or a regime where food was unpredictably unavailable for a 5-h period on 5 days each week. Our measures of energy storage were mass and fat scores. Our measures of somatic maintenance were the growth rate of a plucked feather, and erythrocyte telomere length (TL), measured by analysis of the terminal restriction fragment. The insecure birds were heavier than the controls, by an amount that varied over time. They also had higher fat scores. We found no evidence that they consumed more food overall, though our food consumption data were incomplete. Plucked feathers regrew more slowly in the insecure birds. TL was reduced in the insecure birds, specifically, in the longer percentiles of the within-individual TL distribution. We conclude that increased energy storage in response to food insecurity is achieved at the expense of investment in somatic maintenance and repair.
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Affiliation(s)
- Clare Andrews
- Department of Psychology, University of Stirling, Stirling, UK
| | - Erica Zuidersma
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Daniel Nettle
- Newcastle University Population Health Sciences Institute, Newcastle University, Newcastle, UK
| | - Melissa Bateson
- Newcastle University Biosciences Institute, Newcastle University, Newcastle, UK
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10
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Criscuolo F, Pillay N, Zahn S, Schradin C. Seasonal variation in telomere dynamics in African striped mice. Oecologia 2020; 194:609-620. [DOI: 10.1007/s00442-020-04801-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 11/05/2020] [Indexed: 02/08/2023]
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11
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Casagrande S, Stier A, Monaghan P, Loveland JL, Boner W, Lupi S, Trevisi R, Hau M. Increased glucocorticoid concentrations in early life cause mitochondrial inefficiency and short telomeres. J Exp Biol 2020; 223:jeb222513. [PMID: 32532864 DOI: 10.1242/jeb.222513] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 06/04/2020] [Indexed: 12/13/2022]
Abstract
Telomeres are DNA structures that protect chromosome ends. However, telomeres shorten during cell replication and at critically low lengths can reduce cell replicative potential, induce cell senescence and decrease fitness. Stress exposure, which elevates glucocorticoid hormone concentrations, can exacerbate telomere attrition. This phenomenon has been attributed to increased oxidative stress generated by glucocorticoids ('oxidative stress hypothesis'). We recently suggested that glucocorticoids could increase telomere attrition during stressful periods by reducing the resources available for telomere maintenance through changes in the metabolic machinery ('metabolic telomere attrition hypothesis'). Here, we tested whether experimental increases in glucocorticoid levels affected telomere length and mitochondrial function in wild great tit (Parus major) nestlings during the energy-demanding early growth period. We monitored resulting corticosterone (Cort) concentrations in plasma and red blood cells, telomere lengths and mitochondrial metabolism (metabolic rate, proton leak, oxidative phosphorylation, maximal mitochondrial capacity and mitochondrial inefficiency). We assessed oxidative damage caused by reactive oxygen species (ROS) metabolites as well as the total non-enzymatic antioxidant protection in plasma. Compared with control nestlings, Cort-nestlings had higher baseline corticosterone, shorter telomeres and higher mitochondrial metabolic rate. Importantly, Cort-nestlings showed increased mitochondrial proton leak, leading to a decreased ATP production efficiency. Treatment groups did not differ in oxidative damage or antioxidants. Hence, glucocorticoid-induced telomere attrition is associated with changes in mitochondrial metabolism, but not with ROS production. These findings support the hypothesis that shortening of telomere length during stressful periods is mediated by glucocorticoids through metabolic rearrangements.
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Affiliation(s)
- Stefania Casagrande
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, 82319 Seewiesen, Germany
| | - Antoine Stier
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
- Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Pat Monaghan
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Jasmine L Loveland
- Max Planck Institute for Ornithology, Behavioural Genetics and Evolutionary Ecology Group, 82319 Seewiesen, Germany
| | - Winifred Boner
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Sara Lupi
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, 82319 Seewiesen, Germany
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, A-1160 Vienna, Austria
| | - Rachele Trevisi
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, 82319 Seewiesen, Germany
| | - Michaela Hau
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, 82319 Seewiesen, Germany
- Department of Biology, University of Konstanz, D-78464 Konstanz, Germany
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12
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Grunst ML, Raap T, Grunst AS, Pinxten R, Parenteau C, Angelier F, Eens M. Early-life exposure to artificial light at night elevates physiological stress in free-living songbirds ☆. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 259:113895. [PMID: 31926393 DOI: 10.1016/j.envpol.2019.113895] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/27/2019] [Accepted: 12/28/2019] [Indexed: 06/10/2023]
Abstract
Artificial light at night (ALAN) can disrupt adaptive patterns of physiology and behavior that promote high fitness, resulting in physiological stress and elevation of steroid glucocorticoids (corticosterone, CORT in birds). Elevated CORT may have particularly profound effects early in life, with the potential for enduring effects that persist into adulthood. Research on the consequences of early-life exposure to ALAN remains limited, especially outside of the laboratory, and whether light exposure affects CORT concentrations in wild nestling birds particularly remains to be elucidated. We used an experimental setup to test the hypothesis that ALAN elevates CORT concentrations in developing free-living birds, by exposing nestling great tits (Parus major) to ALAN inside nest boxes. We measured CORT in feathers grown over the timeframe of the experiment (7 nights), such that CORT concentrations represent an integrative metric of hormone release over the period of nocturnal light exposure, and of development. We also assessed the relationships between feather CORT concentrations, body condition, nestling size rank and fledging success. In addition, we evaluated the relationship between feather CORT concentrations and telomere length. Nestlings exposed to ALAN had higher feather CORT concentrations than control nestlings, and nestlings in poorer body condition and smaller brood members also had higher CORT. On the other hand, telomere length, fledging success, and recruitment rate were not significantly associated with light exposure or feather CORT concentrations. Results indicate that exposure to ALAN elevates CORT concentrations in nestlings, which may reflect physiological stress. In addition, the organizational effects of CORT are known to be substantial. Thus, despite the lack of an effect on telomere length and survivorship, elevated CORT concentrations in nestlings exposed to ALAN may have subsequent impacts on later-life fitness and stress sensitivity.
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Affiliation(s)
- Melissa L Grunst
- Department of Biology, Behavioural Ecology and Ecophysiology Group, University of Antwerp, 2610, Wilrijk, Belgium.
| | - Thomas Raap
- Department of Biology, Behavioural Ecology and Ecophysiology Group, University of Antwerp, 2610, Wilrijk, Belgium
| | - Andrea S Grunst
- Department of Biology, Behavioural Ecology and Ecophysiology Group, University of Antwerp, 2610, Wilrijk, Belgium
| | - Rianne Pinxten
- Department of Biology, Behavioural Ecology and Ecophysiology Group, University of Antwerp, 2610, Wilrijk, Belgium; Faculty of Social Sciences, Didactica Research Group, University of Antwerp, 2000, Antwerp, Belgium
| | - Charline Parenteau
- Centre d'Etudes Biologiques de Chizé, CNRS-ULR, UMR 7372, Villiers en Bois, France
| | - Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, CNRS-ULR, UMR 7372, Villiers en Bois, France
| | - Marcel Eens
- Department of Biology, Behavioural Ecology and Ecophysiology Group, University of Antwerp, 2610, Wilrijk, Belgium
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13
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Abstract
Stress exposure can leave long-term footprints within the organism, like in telomeres (TLs), protective chromosome caps that shorten during cell replication and following exposure to stressors. Short TLs are considered to indicate lower fitness prospects, but why TLs shorten under stressful conditions is not understood. Glucocorticoid hormones (GCs) increase upon stress exposure and are thought to promote TL shortening by increasing oxidative damage. However, evidence that GCs are pro-oxidants and oxidative stress is causally linked to TL attrition is mixed . Based on new biochemical findings, we propose the metabolic telomere attrition hypothesis: during times of substantially increased energy demands, TLs are shortened as part of the transition into an organismal 'emergency state', which prioritizes immediate survival functions over processes with longer-term benefits. TL attrition during energy shortages could serve multiple roles including amplified signalling of cellular energy debt to re-direct critical resources to immediately important processes. This new view of TL shortening as a strategy to resolve major energetic trade-offs can improve our understanding of TL dynamics. We suggest that TLs are master regulators of cell homeostasis and propose future research avenues to understand the interactions between energy homeostasis, metabolic regulators and TL.
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Affiliation(s)
- Stefania Casagrande
- 1 Research Group Evolutionary Physiology, Max Planck Institute for Ornithology , 82319 Seewiesen , Germany
| | - Michaela Hau
- 1 Research Group Evolutionary Physiology, Max Planck Institute for Ornithology , 82319 Seewiesen , Germany.,2 Department of Biology, University of Konstanz , D-78457 Konstanz , Germany
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14
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Atema E, Mulder E, van Noordwijk AJ, Verhulst S. Ultralong telomeres shorten with age in nestling great tits but are static in adults and mask attrition of short telomeres. Mol Ecol Resour 2019; 19:648-658. [PMID: 30672119 PMCID: PMC6849772 DOI: 10.1111/1755-0998.12996] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 08/08/2018] [Indexed: 11/29/2022]
Abstract
Telomere length (TL) is increasingly being used as a biomarker of senescence, but measuring telomeres remains a challenge. Within tissue samples, TL varies between cells and chromosomes. Class I telomeres are (presumably static) interstitial telomeric sequences, while terminal telomeres have been divided in shorter (Class II) telomeres and ultralong (Class III) telomeres, and the presence of the latter varies strongly between species. Class II telomeres typically shorten with age, but little is known of Class III telomere dynamics. Using multiple experimental approaches, we show great tits to have ultralong telomeres, and we investigated age effects on Class II and III telomeres using a longitudinal approach (our method excludes Class I telomeres). In adults, TL averaged over the whole distribution did not significantly change with age. However, more detailed analyses showed that Class II TL did shorten with age, and, as in other species, the longest Class II telomeres within individuals shortened more quickly with age. In contrast, Class III TL did not shorten with age within individual adults. Surprisingly, we found the opposite pattern in nestlings: Class III TL shortened significantly with age, while the age effect on Class II TL was close to zero. Thus, Class III TL may provide information on developmental history, while Class II TL provides information on telomere dynamics in adulthood. These findings have practical implications for telomere studies and raise the interesting question of what causes variation in TL dynamics between chromosomes within individuals and how this is related to development.
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Affiliation(s)
- Els Atema
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.,Groningen Institute of Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Ellis Mulder
- Groningen Institute of Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Arie J van Noordwijk
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Simon Verhulst
- Groningen Institute of Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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Fragueira R, Verhulst S, Beaulieu M. Morph- and sex-specific effects of challenging conditions on maintenance parameters in the Gouldian finch. J Exp Biol 2019; 222:jeb196030. [PMID: 30846534 DOI: 10.1242/jeb.196030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 03/04/2019] [Indexed: 12/17/2023]
Abstract
Intraspecific discrete polymorphism is associated with the use of alternative life-history strategies, reflected by distinct reproductive or copying strategies in individuals of different morphs. Yet, morph-specific costs and benefits related to different life-history strategies remain unclear. Here, we examined in the polymorphic Gouldian finch (Erythrura gouldiae) whether markers of somatic maintenance (body mass, oxidative status and telomere length) differed between red- and black-headed birds under energetically demanding conditions (during heatwaves of different intensity, and during moult or breeding following heatwaves). During heatwaves, red-headed birds showed a homogeneous response, as males and females initially tended to gain mass and had reduced plasma hydroperoxide levels (a marker of oxidative damage) irrespective of heatwave intensity. In contrast, black-headed birds showed a stronger and more heterogeneous response, as black-headed males gained mass at the beginning of the thermoneutral heatwave and showed stable oxidative status, whereas black-headed females lost mass and tended to show higher hydroperoxide levels at the end of the thermocritical heatwave. Following heatwaves, we found morph-specific oxidative costs owing to moult or reproduction, with oxidative markers varying only in black-headed birds. Again, oxidative markers varied differently in black-headed males and females, as plasma antioxidant capacity decreased in moulting or breeding females, whereas males showed higher hydroperoxide levels with larger broods. For the first time, our study highlights that within polymorphic species, some individuals appear more vulnerable than others when coping with energetically demanding conditions. In the context of climate change, such differential effects may ultimately alter the currently observed balance between morphs and sexes within natural populations.
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Affiliation(s)
- Rita Fragueira
- Department of Animal Ecology, Zoological Institute and Museum, University of Greifswald, 17489 Greifswald, Germany
| | - Simon Verhulst
- Department of Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747AG Groningen, The Netherlands
| | - Michaël Beaulieu
- Department of Animal Ecology, Zoological Institute and Museum, University of Greifswald, 17489 Greifswald, Germany
- Science Department, German Oceanographic Museum, 18439 Stralsund, Germany
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