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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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2
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Le Clercq LS, Kotzé A, Grobler JP, Dalton DL. Biological clocks as age estimation markers in animals: a systematic review and meta-analysis. Biol Rev Camb Philos Soc 2023; 98:1972-2011. [PMID: 37356823 DOI: 10.1111/brv.12992] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 06/04/2023] [Accepted: 06/08/2023] [Indexed: 06/27/2023]
Abstract
Various biological attributes associated with individual fitness in animals change predictably over the lifespan of an organism. Therefore, the study of animal ecology and the work of conservationists frequently relies upon the ability to assign animals to functionally relevant age classes to model population fitness. Several approaches have been applied to determining individual age and, while these methods have proved useful, they are not without limitations and often lack standardisation or are only applicable to specific species. For these reasons, scientists have explored the potential use of biological clocks towards creating a universal age-determination method. Two biological clocks, tooth layer annulation and otolith layering have found universal appeal. Both methods are highly invasive and most appropriate for post-mortem age-at-death estimation. More recently, attributes of cellular ageing previously explored in humans have been adapted to studying ageing in animals for the use of less-invasive molecular methods for determining age. Here, we review two such methods, assessment of methylation and telomere length, describing (i) what they are, (ii) how they change with age, and providing (iii) a summary and meta-analysis of studies that have explored their utility in animal age determination. We found that both attributes have been studied across multiple vertebrate classes, however, telomere studies were used before methylation studies and telomere length has been modelled in nearly twice as many studies. Telomere length studies included in the review often related changes to stress responses and illustrated that telomere length is sensitive to environmental and social stressors and, in the absence of repair mechanisms such as telomerase or alternative lengthening modes, lacks the ability to recover. Methylation studies, however, while also detecting sensitivity to stressors and toxins, illustrated the ability to recover from such stresses after a period of accelerated ageing, likely due to constitutive expression or reactivation of repair enzymes such as DNA methyl transferases. We also found that both studied attributes have parentally heritable features, but the mode of inheritance differs among taxa and may relate to heterogamy. Our meta-analysis included more than 40 species in common for methylation and telomere length, although both analyses included at least 60 age-estimation models. We found that methylation outperforms telomere length in terms of predictive power evidenced from effect sizes (more than double that observed for telomeres) and smaller prediction intervals. Both methods produced age correlation models using similar sample sizes and were able to classify individuals into young, middle, or old age classes with high accuracy. Our review and meta-analysis illustrate that both methods are well suited to studying age in animals and do not suffer significantly from variation due to differences in the lifespan of the species, genome size, karyotype, or tissue type but rather that quantitative method, patterns of inheritance, and environmental factors should be the main considerations. Thus, provided that complex factors affecting the measured trait can be accounted for, both methylation and telomere length are promising targets to develop as biomarkers for age determination in animals.
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Affiliation(s)
- Louis-Stéphane Le Clercq
- South African National Biodiversity Institute, P.O. Box 754, Pretoria, 0001, South Africa
- Department of Genetics, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa
| | - Antoinette Kotzé
- South African National Biodiversity Institute, P.O. Box 754, Pretoria, 0001, South Africa
- Department of Genetics, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa
| | - J Paul Grobler
- Department of Genetics, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa
| | - Desiré Lee Dalton
- School of Health and Life Sciences, Teesside University, Middlesbrough, TS1 3BA, UK
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Peers MJL, Majchrzak YN, Studd EK, Menzies AK, Kukka PM, Konkolics SM, Boonstra R, Boutin S, Jung TS. Evaluation of Gum‐line Recession for Aging Lynx (
Lynx canadensis
). WILDLIFE SOC B 2021. [DOI: 10.1002/wsb.1239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Michael J. L. Peers
- Department of Biological Sciences University of Alberta Edmonton Alberta T6G 2R3 Canada
| | - Yasmine N. Majchrzak
- Department of Biological Sciences University of Alberta Edmonton Alberta T6G 2R3 Canada
| | - Emily K. Studd
- Department of Natural Resource Sciences McGill University Montréal Québec H9X 3V9 Canada
| | - Allyson K. Menzies
- Department of Natural Resource Sciences McGill University Montréal Québec H9X 3V9 Canada
| | - Piia M. Kukka
- Department of Environment Government of Yukon Whitehorse Yukon Y1A 2C6 Canada
| | - Sean M. Konkolics
- Department of Biological Sciences University of Alberta Edmonton Alberta T6G 2R3 Canada
| | - Rudy Boonstra
- Department of Biological Sciences University of Toronto Scarborough Toronto Ontario M1C 1A4 Canada
| | - Stan Boutin
- Department of Biological Sciences University of Alberta Edmonton Alberta T6G 2R3 Canada
| | - Thomas S. Jung
- Department of Environment Government of Yukon Whitehorse Yukon Y1A 2C6 Canada
- Department of Renewable Resources University of Alberta Edmonton Alberta T6G 2H1 Canada
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de Abechuco EL, Hartmann N, Soto M, Díez G. Assessing the variability of telomere length measures by means of Telomeric Restriction Fragments (TRF) in different tissues of cod Gadus morhua. GENE REPORTS 2016. [DOI: 10.1016/j.genrep.2016.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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6
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Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap Method. DIVERSITY-BASEL 2016. [DOI: 10.3390/d8010003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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7
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Jarman SN, Polanowski AM, Faux CE, Robbins J, De Paoli-Iseppi R, Bravington M, Deagle BE. Molecular biomarkers for chronological age in animal ecology. Mol Ecol 2016; 24:4826-47. [PMID: 26308242 DOI: 10.1111/mec.13357] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/08/2015] [Accepted: 08/21/2015] [Indexed: 01/07/2023]
Abstract
The chronological age of an individual animal predicts many of its biological characteristics, and these in turn influence population-level ecological processes. Animal age information can therefore be valuable in ecological research, but many species have no external features that allow age to be reliably determined. Molecular age biomarkers provide a potential solution to this problem. Research in this area of molecular ecology has so far focused on a limited range of age biomarkers. The most commonly tested molecular age biomarker is change in average telomere length, which predicts age well in a small number of species and tissues, but performs poorly in many other situations. Epigenetic regulation of gene expression has recently been shown to cause age-related modifications to DNA and to cause changes in abundance of several RNA types throughout animal lifespans. Age biomarkers based on these epigenetic changes, and other new DNA-based assays, have already been applied to model organisms, humans and a limited number of wild animals. There is clear potential to apply these marker types more widely in ecological studies. For many species, these new approaches will produce age estimates where this was previously impractical. They will also enable age information to be gathered in cross-sectional studies and expand the range of demographic characteristics that can be quantified with molecular methods. We describe the range of molecular age biomarkers that have been investigated to date and suggest approaches for developing the newer marker types as age assays in nonmodel animal species.
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Affiliation(s)
- Simon N Jarman
- Australian Antarctic Division, 203 Channel Highway, Kingston, Tas., 7050, Australia
| | - Andrea M Polanowski
- Australian Antarctic Division, 203 Channel Highway, Kingston, Tas., 7050, Australia
| | - Cassandra E Faux
- Australian Antarctic Division, 203 Channel Highway, Kingston, Tas., 7050, Australia
| | - Jooke Robbins
- Center for Coastal Studies, 5 Holway Avenue, Provincetown, MA, 02657, USA
| | - Ricardo De Paoli-Iseppi
- Australian Antarctic Division, 203 Channel Highway, Kingston, Tas., 7050, Australia.,Institute of Marine and Antarctic Studies, University of Tasmania, Castray Esplanade, Hobart, Tas., 7000, Australia
| | - Mark Bravington
- Marine Laboratory, Commonwealth Scientific and Industrial Research Organisation, Castray Esplanade, Hobart, Tas., 7000, Australia
| | - Bruce E Deagle
- Australian Antarctic Division, 203 Channel Highway, Kingston, Tas., 7050, Australia
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Dantzer B, Fletcher QE. Telomeres shorten more slowly in slow-aging wild animals than in fast-aging ones. Exp Gerontol 2015; 71:38-47. [DOI: 10.1016/j.exger.2015.08.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/21/2015] [Accepted: 08/22/2015] [Indexed: 01/01/2023]
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Young RC, Kitaysky AS, Barger CP, Dorresteijn I, Ito M, Watanuki Y. Telomere length is a strong predictor of foraging behavior in a long-lived seabird. Ecosphere 2015. [DOI: 10.1890/es14-00345.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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10
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O’Mahony DT, Turner P, O’Reilly C. Pine marten (Martes martes) abundance in an insular mountainous region using non-invasive techniques. EUR J WILDLIFE RES 2014. [DOI: 10.1007/s10344-014-0878-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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11
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Davidson GA, Clark DA, Johnson BK, Waits LP, Adams JR. Estimating cougar densities in northeast Oregon using conservation detection dogs. J Wildl Manage 2014. [DOI: 10.1002/jwmg.758] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Darren A. Clark
- Oregon Cooperative Fish and Wildlife Research Unit; Department of Fisheries and Wildlife; Oregon State University; Corvallis OR 97331 USA
| | | | - Lisette P. Waits
- Department of Fish and Wildlife Sciences; University of Idaho; Moscow ID 83844-1136 USA
| | - Jennifer R. Adams
- Department of Fish and Wildlife Sciences; University of Idaho; Moscow ID 83844-1136 USA
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12
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Cope RC, Lanyon JM, Seddon JM, Pollett PK. Development and testing of a genetic marker-based pedigree reconstruction system 'PR-genie' incorporating size-class data. Mol Ecol Resour 2014; 14:857-70. [PMID: 24373173 DOI: 10.1111/1755-0998.12219] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 12/02/2013] [Accepted: 12/11/2013] [Indexed: 11/28/2022]
Abstract
For wildlife populations, it is often difficult to determine biological parameters that indicate breeding patterns and population mixing, but knowledge of these parameters is essential for effective management. A pedigree encodes the relationship between individuals and can provide insight into the dynamics of a population over its recent history. Here, we present a method for the reconstruction of pedigrees for wild populations of animals that live long enough to breed multiple times over their lifetime and that have complex or unknown generational structures. Reconstruction was based on microsatellite genotype data along with ancillary biological information: sex and observed body size class as an indicator of relative age of individuals within the population. Using body size-class data to infer relative age has not been considered previously in wildlife genealogy and provides a marked improvement in accuracy of pedigree reconstruction. Body size-class data are particularly useful for wild populations because it is much easier to collect noninvasively than absolute age data. This new pedigree reconstruction system, PR-genie, performs reconstruction using maximum likelihood with optimization driven by the cross-entropy method. We demonstrated pedigree reconstruction performance on simulated populations (comparing reconstructed pedigrees to known true pedigrees) over a wide range of population parameters and under assortative and intergenerational mating schema. Reconstruction accuracy increased with the presence of size-class data and as the amount and quality of genetic data increased. We provide recommendations as to the amount and quality of data necessary to provide insight into detailed familial relationships in a wildlife population using this pedigree reconstruction technique.
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Affiliation(s)
- Robert C Cope
- School of Biological Science, The University of Queensland, St Lucia, Qld, 4072, Australia
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Brzeski KE, Gunther MS, Black JM. Evaluating river otter demography using noninvasive genetic methods. J Wildl Manage 2013. [DOI: 10.1002/jwmg.610] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | | | - Jeffrey M. Black
- Department of Wildlife; Humboldt State University; Arcata CA 95521 USA
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14
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Johnson CJ, Hodder DP, Crowley S. Assessing noninvasive hair and fecal sampling for monitoring the distribution and abundance of river otter. Ecol Res 2013. [DOI: 10.1007/s11284-013-1071-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Guertin DA, Ben-David M, Harestad AS, Elliott JE. Fecal genotyping reveals demographic variation in river otters inhabiting a contaminated environment. J Wildl Manage 2012. [DOI: 10.1002/jwmg.439] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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