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Wolf SE, Woodruff MJ, Chang van Oordt DA, Clotfelter ED, Cristol DA, Derryberry EP, Ferguson SM, Stanback MT, Taff CC, Vitousek MN, Westneat DF, Rosvall KA. Among-population variation in telomere regulatory proteins and their potential role as hidden drivers of intraspecific variation in life history. J Anim Ecol 2024. [PMID: 38509838 DOI: 10.1111/1365-2656.14071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 01/14/2024] [Indexed: 03/22/2024]
Abstract
Biologists aim to explain patterns of growth, reproduction and ageing that characterize life histories, yet we are just beginning to understand the proximate mechanisms that generate this diversity. Existing research in this area has focused on telomeres but has generally overlooked the telomere's most direct mediator, the shelterin protein complex. Shelterin proteins physically interact with the telomere to shape its shortening and repair. They also regulate metabolism and immune function, suggesting a potential role in life history variation in the wild. However, research on shelterin proteins is uncommon outside of biomolecular work. Intraspecific analyses can play an important role in resolving these unknowns because they reveal subtle variation in life history within and among populations. Here, we assessed ecogeographic variation in shelterin protein abundance across eight populations of tree swallow (Tachycineta bicolor) with previously documented variation in environmental and life history traits. Using the blood gene expression of four shelterin proteins in 12-day-old nestlings, we tested the hypothesis that shelterin protein gene expression varies latitudinally and in relation to both telomere length and life history. Shelterin protein gene expression differed among populations and tracked non-linear variation in latitude: nestlings from mid-latitudes expressed nearly double the shelterin mRNA on average than those at more northern and southern sites. However, telomere length was not significantly related to latitude. We next assessed whether telomere length and shelterin protein gene expression correlate with 12-day-old body mass and wing length, two proxies of nestling growth linked to future fecundity and survival. We found that body mass and wing length correlated more strongly (and significantly) with shelterin protein gene expression than with telomere length. These results highlight telomere regulatory shelterin proteins as potential mediators of life history variation among populations. Together with existing research linking shelterin proteins and life history variation within populations, these ecogeographic patterns underscore the need for continued integration of ecology, evolution and telomere biology, which together will advance understanding of the drivers of life history variation in nature.
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Affiliation(s)
- Sarah E Wolf
- Department of Biology, Indiana University, Bloomington, Indiana, USA
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Mary J Woodruff
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - David A Chang van Oordt
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
- Cornell Lab of Ornithology, Ithaca, New York, USA
| | | | - Daniel A Cristol
- Department of Biology, William & Mary, Williamsburg, Virginia, USA
| | - Elizabeth P Derryberry
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Stephen M Ferguson
- Department of Biology, University of Kentucky, Lexington, Kentucky, USA
- Department of Biology, University of Richmond, Richmond, Virginia, USA
| | - Mark T Stanback
- Department of Biology, Davidson College, Davidson, North Carolina, USA
| | - Conor C Taff
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
- Cornell Lab of Ornithology, Ithaca, New York, USA
| | - Maren N Vitousek
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
- Cornell Lab of Ornithology, Ithaca, New York, USA
| | - David F Westneat
- Department of Biology, University of Kentucky, Lexington, Kentucky, USA
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Gómez‐Blanco D, Tobler M, Hasselquist D. Why and when should organisms elongate their telomeres? Elaborations on the 'excess resources elongation' and 'last resort elongation' hypotheses. Ecol Evol 2023; 13:e10825. [PMID: 38099139 PMCID: PMC10719541 DOI: 10.1002/ece3.10825] [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: 02/17/2023] [Revised: 10/31/2023] [Accepted: 11/28/2023] [Indexed: 12/17/2023] Open
Abstract
Telomere length and telomere shortening are thought to be critical cellular attributes and processes that are related to an individual's life span and fitness. The general pattern across most taxa is that after birth telomere length gradually decreases with age. Telomere protection and restoration mechanisms are usually assumed to reduce the rate of shortening or at most keep telomere length constant. However, here we have compiled a list of 26 articles showing that there is an increasing number of studies reporting apparent elongation of telomeres (i.e., a net increase in TL from timet to timet+1) often in a considerable proportion of the individuals studied. Moreover, the few studies which have studied telomere elongation in detail show that increases in telomere length are unlikely to be due to measurement error alone. In this article, we argue that episodes of telomere elongation deserve more attention as they could reflect individual strategies to optimise life histories and maximise fitness, which may not be reflected in the overall telomere dynamics patterns. We propose that patterns of telomere (net) elongation may be partly determined by other factors than those causing telomere shortening, and therefore deserve analyses specifically targeted to investigate the occurrence of telomere elongation. We elaborate on two ecological hypotheses that have been proposed to explain patterns of telomere elongation (the 'excess resources elongation' and the 'last resort elongation' hypothesis) and we discuss the current evidence for (or against) these hypotheses and propose ways to test them.
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Wolf SE, Shalev I. The shelterin protein expansion of telomere dynamics: Linking early life adversity, life history, and the hallmarks of aging. Neurosci Biobehav Rev 2023; 152:105261. [PMID: 37268182 PMCID: PMC10527177 DOI: 10.1016/j.neubiorev.2023.105261] [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: 01/27/2023] [Revised: 04/10/2023] [Accepted: 05/30/2023] [Indexed: 06/04/2023]
Abstract
Aging is characterized by functional decline occurring alongside changes to several hallmarks of aging. One of the hallmarks includes attrition of repeated DNA sequences found at the ends of chromosomes called telomeres. While telomere attrition is linked to morbidity and mortality, whether and how it causally contributes to lifelong rates of functional decline is unclear. In this review, we propose the shelterin-telomere hypothesis of life history, in which telomere-binding shelterin proteins translate telomere attrition into a range of physiological outcomes, the extent of which may be modulated by currently understudied variation in shelterin protein levels. Shelterin proteins may expand the breadth and timing of consequences of telomere attrition, e.g., by translating early life adversity into acceleration of the aging process. We consider how the pleiotropic roles of shelterin proteins provide novel insights into natural variation in physiology, life history, and lifespan. We highlight key open questions that encourage the integrative, organismal study of shelterin proteins that enhances our understanding of the contribution of the telomere system to aging.
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Affiliation(s)
- Sarah E Wolf
- Department of Biobehavioral Health, Penn State University, University Park, PA 16802, USA.
| | - Idan Shalev
- Department of Biobehavioral Health, Penn State University, University Park, PA 16802, USA
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Voirin CJ, Tsunekage T, Liu Y, Alexy KF, Levin II. Brood size is associated with apparent telomere lengthening in nestling barn swallows. Oecologia 2023; 202:29-40. [PMID: 37087699 DOI: 10.1007/s00442-023-05375-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 04/12/2023] [Indexed: 04/24/2023]
Abstract
Early life for animals is often a time of rapid growth and development. In a resource-limited environment, life history theory predicts that there must be trade-offs between resource sinks in ways that optimize future survival and reproductive success. Telomeres have emerged as putative indicators of these early life trade-offs, but there are conflicting accounts as to how developmental traits and conditions impact telomere length and dynamics. For 2 years, we studied the nestlings of a breeding population of barn swallows from day 6 to day 12 of life, measuring various ontogenetic factors to understand to what extent they explain variation in telomere length and dynamics. We unexpectedly found that telomeres lengthened between the two sampling points. Nestlings in large broods had shorter telomeres, but surprisingly, individuals that grew faster from day 6 to day 12 had longer telomeres and more telomere lengthening. Nestlings with higher mass relative to their nestmates on d6 had shorter telomeres, suggesting that the relatively fast growth barn swallows experience early in development is more costly than the relatively slower growth later in development. These effects were only found in the first year of study. Telomere lengthening may be due to the initiation of new hematopoietic cell lines during development or the expression of telomerase early in life. Favorable early life conditions and high parental investment could allow for more growth with little to no cost to telomere length or dynamics.
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Affiliation(s)
| | - Toshi Tsunekage
- Department of Biology, Kenyon College, Gambier, OH, 43022, USA
| | - Yujie Liu
- Department of Biology, Kenyon College, Gambier, OH, 43022, USA
| | - Kate F Alexy
- Department of Biology, Kenyon College, Gambier, OH, 43022, USA
| | - Iris I Levin
- Department of Biology, Kenyon College, Gambier, OH, 43022, USA
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Wolf SE, Zhang S, Clotfelter ED. Experimental ectoparasite removal has a sex-specific effect on nestling telomere length. Ecol Evol 2023; 13:e9861. [PMID: 36911306 PMCID: PMC9992774 DOI: 10.1002/ece3.9861] [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: 10/09/2022] [Revised: 02/02/2023] [Accepted: 02/06/2023] [Indexed: 03/11/2023] Open
Abstract
Parasites are a strong selective force that can influence fitness-related traits. The length of chromosome-capping telomeres can be used to assess the long-term costs of parasitism, as telomere loss accelerates in response to environmental stressors and often precedes poorer survival prospects. Here, we explored the sex-specific effects of ectoparasite removal on morphology and telomere length in nestling tree swallows (Tachycineta bicolor). To do so, we experimentally removed blow fly (Protocalliphora spp.) larvae from nests using Permethrin, a broad-spectrum insecticide. Compared to water-treated controls, insecticide treatment of nests had a sex-biased effect on blood telomere length: ectoparasite removal resulted in significantly longer telomeres in males but not females. While this treatment did not influence nestling body mass, it was associated with reduced feather development regardless of sex. This may reflect a relaxed pressure to fledge quickly in the absence of parasites, or alternatively, could be a negative side effect of permethrin on morphology. Exploring robust sex-specific telomere dynamics in response to early-life environmental pressures such as parasitism will shed light on sexual dimorphism in adult life histories and aging.
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Affiliation(s)
- Sarah E Wolf
- Department of Biology Indiana University Bloomington Indiana USA.,Department of Biobehavioral Health Pennsylvania State University State College Pennsylvania USA
| | - Samuel Zhang
- Department of Biology Amherst College Amherst Massachusetts USA
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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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