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Taylor GT, McQueen A, Eastwood JR, Dupoué A, Wong BBM, Verhulst S, Peters A. No effect of testosterone or sexual ornamentation on telomere dynamics: A case study and meta-analyses. Ecol Evol 2024; 14:e11088. [PMID: 38435019 PMCID: PMC10905238 DOI: 10.1002/ece3.11088] [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: 12/15/2023] [Revised: 02/11/2024] [Accepted: 02/16/2024] [Indexed: 03/05/2024] Open
Abstract
Life-history theory predicts that reproductive investments are traded-off against self-maintenance. Telomeres, the protective caps on the ends of chromosomes, offer a promising avenue for assessing life-history trade-offs, as they shorten in response to stressors and are predictive of the remaining lifespan. In males, testosterone frequently mediates life-history trade-offs, in part, through its effects on sexual ornamentation, which is an important aspect of reproductive investment. However, studies of within-individual associations between telomere dynamics and sexual ornamentation are limited in number and have produced mixed results. Furthermore, most such studies have been observational, making it difficult to discern the nature of any causal relationship. To address this, we used short-acting testosterone implants in free-living male superb fairy-wrens (Malurus cyaneus) to stimulate the production of a sexual ornament: early moult into a costly blue breeding plumage. We found no evidence that elevated testosterone, and the consequent earlier moult into breeding plumage, accelerated telomere shortening. We therefore followed up with a systematic review and two meta-analyses (28 studies, 54 effect sizes) exploring the associations between telomeres and (1) testosterone and (2) sexual ornamentation. In line with our experimental findings, neither meta-analysis showed an overall correlation of testosterone or sexual ornamentation with telomere length or telomere dynamics. However, meta-regression showed that experimental, compared to observational, studies reported greater evidence of trade-offs. Our meta-analyses highlight the need for further experimental studies to better understand potential responses of telomere length or telomere dynamics to testosterone or sexual ornamentation.
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Affiliation(s)
- Gregory T. Taylor
- School of Biological SciencesMonash UniversityClaytonVictoriaAustralia
| | - Alexandra McQueen
- School of Biological SciencesMonash UniversityClaytonVictoriaAustralia
- Present address:
Centre for Integrative EcologyDeakin UniversityBurwoodVictoriaAustralia
| | | | - Andréaz Dupoué
- School of Biological SciencesMonash UniversityClaytonVictoriaAustralia
- Present address:
CNRS Sorbonne Université, UMR 7618, iEES ParisUniversité Pierre et Marie CurieParisFrance
| | - Bob B. M. Wong
- School of Biological SciencesMonash UniversityClaytonVictoriaAustralia
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Anne Peters
- School of Biological SciencesMonash UniversityClaytonVictoriaAustralia
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Jimeno B, Verhulst S. Meta-analysis reveals glucocorticoid levels reflect variation in metabolic rate, not 'stress'. eLife 2023; 12:RP88205. [PMID: 37889839 PMCID: PMC10611431 DOI: 10.7554/elife.88205] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2023] Open
Abstract
Glucocorticoid (GC) variation has long been thought to reflect variation in organismal 'stress,' but associations between GCs and Darwinian fitness components are diverse in magnitude, direction, and highly context-dependent. This paradox reveals our poor understanding of the causes of GC variation, contrasting with the detailed knowledge of the functional consequences of GC variation. Amongst an array of effects in many physiological systems, GCs orchestrate energy availability to anticipate and recover from predictable and unpredictable environmental fluctuations and challenges. Although this is mechanistically well-known, the extent to which GC levels are quantitatively explained by energy metabolism is unresolved. We investigated this association through meta-analysis, selecting studies of endotherms in which (1) an experiment was performed that affected metabolic rate and (2) metabolic rate and GC levels were measured simultaneously. We found that an increase in metabolic rate was associated with an increase in GC levels in 20 out of 21 studies (32 out of 35 effect sizes). More importantly, there was a strong positive correlation between the increases in metabolic rate and GCs (p=0.003). This pattern was similar in birds and mammals, and independent of the nature of the experimental treatment. We conclude that metabolic rate is a major driver of GC variation within individuals. Stressors often affect metabolic rate, leading us to question whether GC levels provide information on 'stress' beyond the stressor's effect on metabolic rate.
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Affiliation(s)
- Blanca Jimeno
- Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC-UCLM-JCC, Ciudad Real, Spain
- Instituto Pirenaico de Ecologia (IPE), CSIC, Avda. Nuestra Señora de la Victoria, Jaca, Spain
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Casagrande S, Loveland JL, Oefele M, Boner W, Lupi S, Stier A, Hau M. Dietary nucleotides can prevent glucocorticoid-induced telomere attrition in a fast-growing wild vertebrate. Mol Ecol 2023; 32:5429-5447. [PMID: 37658759 DOI: 10.1111/mec.17114] [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: 05/11/2023] [Revised: 07/20/2023] [Accepted: 08/09/2023] [Indexed: 09/05/2023]
Abstract
Telomeres are chromosome protectors that shorten during eukaryotic cell replication and in stressful conditions. Developing individuals are susceptible to telomere erosion when their growth is fast and resources are limited. This is critical because the rate of telomere attrition in early life is linked to health and life span of adults. The metabolic telomere attrition hypothesis (MeTA) suggests that telomere dynamics can respond to biochemical signals conveying information about the organism's energetic state. Among these signals are glucocorticoids, hormones that promote catabolic processes, potentially impairing costly telomere maintenance, and nucleotides, which activate anabolic pathways through the cellular enzyme target of rapamycin (TOR), thus preventing telomere attrition. During the energetically demanding growth phase, the regulation of telomeres in response to two contrasting signals - one promoting telomere maintenance and the other attrition - provides an ideal experimental setting to test the MeTA. We studied nestlings of a rapidly developing free-living passerine, the great tit (Parus major), that either received glucocorticoids (Cort-chicks), nucleotides (Nuc-chicks) or a combination of both (NucCort-chicks), comparing these with controls (Cnt-chicks). As expected, Cort-chicks showed telomere attrition, while NucCort- and Nuc-chicks did not. NucCort-chicks was the only group showing increased expression of a proxy for TOR activation (the gene TELO2), of mitochondrial enzymes linked to ATP production (cytochrome oxidase and ATP-synthase) and a higher efficiency in aerobically producing ATP. NucCort-chicks had also a higher expression of telomere maintenance genes (shelterin protein TERF2 and telomerase TERT) and of enzymatic antioxidant genes (glutathione peroxidase and superoxide dismutase). The findings show that nucleotide availability is crucial for preventing telomere erosion during fast growth in stressful environments.
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Affiliation(s)
- Stefania Casagrande
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, Seewiesen, Germany
| | - Jasmine L Loveland
- Department of Cognitive and Behavioral Biology, University of Vienna, Vienna, Austria
| | - Marlene Oefele
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, Seewiesen, Germany
| | - Winnie Boner
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Sara Lupi
- Konrad Lorenz Institute of Ethology, Vienna, Austria
| | - Antoine Stier
- Université de Strasbourg, CNRS, Institut Pluridisciplinaire Hubert Curien, UMR7178, Strasbourg, France
- Department of Biology, University of Turku, Turku, Finland
| | - Michaela Hau
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, Seewiesen, Germany
- Department of Biology, University of Konstanz, Constance, Germany
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Longitudinal telomere dynamics within natural lifespans of a wild bird. Sci Rep 2023; 13:4272. [PMID: 36922555 PMCID: PMC10017829 DOI: 10.1038/s41598-023-31435-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 03/11/2023] [Indexed: 03/17/2023] Open
Abstract
Telomeres, the nucleotide sequences that protect the ends of eukaryotic chromosomes, shorten with each cell division and telomere loss may be influenced by environmental factors. Telomere length (TL) decreases with age in several species, but little is known about the sources of genetic and environmental variation in the change in TL (∆TL) in wild animals. In this study, we tracked changes in TL throughout the natural lifespan (from a few months to almost 9 years) of free-living house sparrows (Passer domesticus) in two different island populations. TL was measured in nestlings and subsequently up to four times during their lifetime. TL generally decreased with age (senescence), but we also observed instances of telomere lengthening within individuals. We found some evidence for selective disappearance of individuals with shorter telomeres through life. Early-life TL positively predicted later-life TL, but the within-individual repeatability in TL was low (9.2%). Using genetic pedigrees, we found a moderate heritability of ∆TL (h2 = 0.21), which was higher than the heritabilities of early-life TL (h2 = 0.14) and later-life TL measurements (h2 = 0.15). Cohort effects explained considerable proportions of variation in early-life TL (60%), later-life TL (53%), and ∆TL (37%), which suggests persistent impacts of the early-life environment on lifelong telomere dynamics. Individual changes in TL were independent of early-life TL. Finally, there was weak evidence for population differences in ∆TL that may be linked to ecological differences in habitat types. Combined, our results show that individual telomere biology is highly dynamic and influenced by both genetic and environmental variation in natural conditions.
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Rieseberg L, Warschefsky E, Ortiz-Barrientos D, Kane NC, Thresher K, Sibbett B. Editorial 2023. Mol Ecol 2023; 32:1-25. [PMID: 36573261 DOI: 10.1111/mec.16815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 12/06/2022] [Indexed: 12/28/2022]
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Monaghan P, Olsson M, Richardson DS, Verhulst S, Rogers SM. Integrating telomere biology into the ecology and evolution of natural populations: Progress and prospects. Mol Ecol 2022; 31:5909-5916. [PMID: 36330668 DOI: 10.1111/mec.16768] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Pat Monaghan
- Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, Institute of Biodiversity, University of Glasgow, Glasgow, UK
| | - Mats Olsson
- Department of BioEnv - Zoologen, University of Gothenburg, Gothenburg, Sweden
| | - David S Richardson
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, UK
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Sean M Rogers
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.,Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
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Pepke ML, Kvalnes T, Ranke PS, Araya‐Ajoy YG, Wright J, Sæther B, Jensen H, Ringsby TH. Causes and consequences of variation in early-life telomere length in a bird metapopulation. Ecol Evol 2022; 12:e9144. [PMID: 35923948 PMCID: PMC9339764 DOI: 10.1002/ece3.9144] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 06/24/2022] [Accepted: 07/01/2022] [Indexed: 11/07/2022] Open
Abstract
Environmental conditions during early-life development can have lasting effects shaping individual heterogeneity in fitness and fitness-related traits. The length of telomeres, the DNA sequences protecting chromosome ends, may be affected by early-life conditions, and telomere length (TL) has been associated with individual performance within some wild animal populations. Thus, knowledge of the mechanisms that generate variation in TL, and the relationship between TL and fitness, is important in understanding the role of telomeres in ecology and life-history evolution. Here, we investigate how environmental conditions and morphological traits are associated with early-life blood TL and if TL predicts natal dispersal probability or components of fitness in 2746 wild house sparrow (Passer domesticus) nestlings from two populations sampled across 20 years (1994-2013). We retrieved weather data and we monitored population fluctuations, individual survival, and reproductive output using field observations and genetic pedigrees. We found a negative effect of population density on TL, but only in one of the populations. There was a curvilinear association between TL and the maximum daily North Atlantic Oscillation index during incubation, suggesting that there are optimal weather conditions that result in the longest TL. Dispersers tended to have shorter telomeres than non-dispersers. TL did not predict survival, but we found a tendency for individuals with short telomeres to have higher annual reproductive success. Our study showed how early-life TL is shaped by effects of growth, weather conditions, and population density, supporting that environmental stressors negatively affect TL in wild populations. In addition, shorter telomeres may be associated with a faster pace-of-life, as individuals with higher dispersal rates and annual reproduction tended to have shorter early-life TL.
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Affiliation(s)
- Michael Le Pepke
- Department of Biology, Centre for Biodiversity Dynamics (CBD)Norwegian University of Science and Technology (NTNU)TrondheimNorway
| | - Thomas Kvalnes
- Department of Biology, Centre for Biodiversity Dynamics (CBD)Norwegian University of Science and Technology (NTNU)TrondheimNorway
| | - Peter Sjolte Ranke
- Department of Biology, Centre for Biodiversity Dynamics (CBD)Norwegian University of Science and Technology (NTNU)TrondheimNorway
| | - Yimen G. Araya‐Ajoy
- Department of Biology, Centre for Biodiversity Dynamics (CBD)Norwegian University of Science and Technology (NTNU)TrondheimNorway
| | - Jonathan Wright
- Department of Biology, Centre for Biodiversity Dynamics (CBD)Norwegian University of Science and Technology (NTNU)TrondheimNorway
| | - Bernt‐Erik Sæther
- Department of Biology, Centre for Biodiversity Dynamics (CBD)Norwegian University of Science and Technology (NTNU)TrondheimNorway
| | - Henrik Jensen
- Department of Biology, Centre for Biodiversity Dynamics (CBD)Norwegian University of Science and Technology (NTNU)TrondheimNorway
| | - Thor Harald Ringsby
- Department of Biology, Centre for Biodiversity Dynamics (CBD)Norwegian University of Science and Technology (NTNU)TrondheimNorway
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