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Taff CC, McNew SM, Campagna L, Vitousek MN. Corticosterone exposure is associated with long-term changes in DNA methylation, physiology and breeding decisions in a wild bird. Mol Ecol 2024:e17456. [PMID: 38953311 DOI: 10.1111/mec.17456] [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: 07/31/2023] [Revised: 06/07/2024] [Accepted: 06/24/2024] [Indexed: 07/04/2024]
Abstract
When facing challenges, vertebrates activate a hormonal stress response that can dramatically alter behaviour and physiology. Although this response can be costly, conceptual models suggest that it can also recalibrate the stress response system, priming more effective responses to future challenges. Little is known about whether this process occurs in wild animals, particularly in adulthood, and if so, how information about prior experience with stressors is encoded. One potential mechanism is hormonally mediated changes in DNA methylation. We simulated the spikes in corticosterone that accompany a stress response using non-invasive dosing in tree swallows (Tachycineta bicolor) and monitored the phenotypic effects 1 year later. In a subset of individuals, we characterized DNA methylation using reduced representation bisulfite sequencing shortly after treatment and a year later. The year after treatment, experimental females had stronger negative feedback and initiated breeding earlier-traits that are associated with stress resilience and reproductive performance in our population-and higher baseline corticosterone. We also found that natural variation in corticosterone predicted patterns of DNA methylation. Finally, corticosterone treatment influenced methylation on short (1-2 weeks) and long (1 year) time scales; however, these changes did not have clear links to functional regulation of the stress response. Taken together, our results are consistent with corticosterone-induced priming of future stress resilience and support DNA methylation as a potential mechanism, but more work is needed to demonstrate functional consequences. Uncovering the mechanisms linking experience with the response to future challenges has implications for understanding the drivers of stress resilience.
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Affiliation(s)
- Conor C Taff
- Department of Ecology & Evolutionary Biology and Cornell Lab of Ornithology, Cornell University, Ithaca, New York, USA
- Department of Biology, Colby College, Waterville, Maine, USA
| | - Sabrina M McNew
- Department of Ecology & Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
| | - Leonardo Campagna
- Department of Ecology & Evolutionary Biology and Cornell Lab of Ornithology, Cornell University, Ithaca, New York, USA
| | - Maren N Vitousek
- Department of Ecology & Evolutionary Biology and Cornell Lab of Ornithology, Cornell University, Ithaca, New York, USA
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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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Laine VN, Sepers B, Lindner M, Gawehns F, Ruuskanen S, van Oers K. An ecologist's guide for studying DNA methylation variation in wild vertebrates. Mol Ecol Resour 2023; 23:1488-1508. [PMID: 35466564 DOI: 10.1111/1755-0998.13624] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 03/29/2022] [Accepted: 04/13/2022] [Indexed: 11/30/2022]
Abstract
The field of molecular biology is advancing fast with new powerful technologies, sequencing methods and analysis software being developed constantly. Commonly used tools originally developed for research on humans and model species are now regularly used in ecological and evolutionary research. There is also a growing interest in the causes and consequences of epigenetic variation in natural populations. Studying ecological epigenetics is currently challenging, especially for vertebrate systems, because of the required technical expertise, complications with analyses and interpretation, and limitations in acquiring sufficiently high sample sizes. Importantly, neglecting the limitations of the experimental setup, technology and analyses may affect the reliability and reproducibility, and the extent to which unbiased conclusions can be drawn from these studies. Here, we provide a practical guide for researchers aiming to study DNA methylation variation in wild vertebrates. We review the technical aspects of epigenetic research, concentrating on DNA methylation using bisulfite sequencing, discuss the limitations and possible pitfalls, and how to overcome them through rigid and reproducible data analysis. This review provides a solid foundation for the proper design of epigenetic studies, a clear roadmap on the best practices for correct data analysis and a realistic view on the limitations for studying ecological epigenetics in vertebrates. This review will help researchers studying the ecological and evolutionary implications of epigenetic variation in wild populations.
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Affiliation(s)
- Veronika N Laine
- Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - Bernice Sepers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
- Behavioural Ecology Group, Wageningen University & Research (WUR), Wageningen, The Netherlands
| | - Melanie Lindner
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Fleur Gawehns
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Suvi Ruuskanen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- Department of Biology, University of Turku, Finland
| | - Kees van Oers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
- Behavioural Ecology Group, Wageningen University & Research (WUR), Wageningen, The Netherlands
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4
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Le Clercq LS, Bazzi G, Cecere JG, Gianfranceschi L, Grobler JP, Kotzé A, Rubolini D, Liedvogel M, Dalton DL. Time trees and clock genes: a systematic review and comparative analysis of contemporary avian migration genetics. Biol Rev Camb Philos Soc 2023; 98:1051-1080. [PMID: 36879518 DOI: 10.1111/brv.12943] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/08/2023]
Abstract
Timing is a crucial aspect for survival and reproduction in seasonal environments leading to carefully scheduled annual programs of migration in many species. But what are the exact mechanisms through which birds (class: Aves) can keep track of time, anticipate seasonal changes, and adapt their behaviour? One proposed mechanism regulating annual behaviour is the circadian clock, controlled by a highly conserved set of genes, collectively called 'clock genes' which are well established in controlling the daily rhythmicity of physiology and behaviour. Due to diverse migration patterns observed within and among species, in a seemingly endogenously programmed manner, the field of migration genetics has sought and tested several candidate genes within the clock circuitry that may underlie the observed differences in breeding and migration behaviour. Among others, length polymorphisms within genes such as Clock and Adcyap1 have been hypothesised to play a putative role, although association and fitness studies in various species have yielded mixed results. To contextualise the existing body of data, here we conducted a systematic review of all published studies relating polymorphisms in clock genes to seasonality in a phylogenetically and taxonomically informed manner. This was complemented by a standardised comparative re-analysis of candidate gene polymorphisms of 76 bird species, of which 58 are migrants and 18 are residents, along with population genetics analyses for 40 species with available allele data. We tested genetic diversity estimates, used Mantel tests for spatial genetic analyses, and evaluated relationships between candidate gene allele length and population averages for geographic range (breeding- and non-breeding latitude), migration distance, timing of migration, taxonomic relationships, and divergence times. Our combined analysis provided evidence (i) of a putative association between Clock gene variation and autumn migration as well as a putative association between Adcyap1 gene variation and spring migration in migratory species; (ii) that these candidate genes are not diagnostic markers to distinguish migratory from sedentary birds; and (iii) of correlated variability in both genes with divergence time, potentially reflecting ancestrally inherited genotypes rather than contemporary changes driven by selection. These findings highlight a tentative association between these candidate genes and migration attributes as well as genetic constraints on evolutionary adaptation.
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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, PO Box 339, Bloemfontein, 9300, South Africa
| | - Gaia Bazzi
- Area Avifauna Migratrice, Istituto Superiore per la Protezione e la Ricerca Ambientale, via Ca' Fornacetta 9, Ozzano Emilia (BO), I-40064, Italy
| | - Jacopo G Cecere
- Area Avifauna Migratrice, Istituto Superiore per la Protezione e la Ricerca Ambientale, via Ca' Fornacetta 9, Ozzano Emilia (BO), I-40064, Italy
| | - Luca Gianfranceschi
- Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, Milan, I-20133, Italy
| | - Johannes Paul Grobler
- Department of Genetics, University of the Free State, PO 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, PO Box 339, Bloemfontein, 9300, South Africa
| | - Diego Rubolini
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, via Celoria 26, Milan, I-20133, Italy
- Istituto di Ricerca sulle Acque, IRSA-CNR, Via del Mulino 19, Brugherio (MB), I-20861, Italy
| | - Miriam Liedvogel
- Max Planck Research Group Behavioral Genomics, Max Planck Institute for Evolutionary Biology, Plön, 24306, Germany
- Institute of Avian Research, An der Vogelwarte 21, Wilhelmshaven, 26386, Germany
| | - Desiré Lee Dalton
- School of Health and Life Sciences, Teesside University, Middlesbrough, TS1 3BA, UK
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5
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van Oers K, van den Heuvel K, Sepers B. The Epigenetics of Animal Personality. Neurosci Biobehav Rev 2023; 150:105194. [PMID: 37094740 DOI: 10.1016/j.neubiorev.2023.105194] [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: 10/29/2022] [Revised: 04/12/2023] [Accepted: 04/21/2023] [Indexed: 04/26/2023]
Abstract
Animal personality, consistent individual differences in behaviour, is an important concept for understanding how individuals vary in how they cope with environmental challenges. In order to understand the evolutionary significance of animal personality, it is crucial to understand the underlying regulatory mechanisms. Epigenetic marks such as DNA methylation are hypothesised to play a major role in explaining variation in phenotypic changes in response to environmental alterations. Several characteristics of DNA methylation also align well with the concept of animal personality. In this review paper, we summarise the current literature on the role that molecular epigenetic mechanisms may have in explaining personality variation. We elaborate on the potential for epigenetic mechanisms to explain behavioural variation, behavioural development and temporal consistency in behaviour. We then suggest future routes for this emerging field and point to potential pitfalls that may be encountered. We conclude that a more inclusive approach is needed for studying the epigenetics of animal personality and that epigenetic mechanisms cannot be studied without considering the genetic background.
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Affiliation(s)
- Kees van Oers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands; Behavioural Ecology Group, Wageningen University & Research (WUR), Wageningen, the Netherlands.
| | - Krista van den Heuvel
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands; Behavioural Ecology Group, Wageningen University & Research (WUR), Wageningen, the Netherlands
| | - Bernice Sepers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands; Behavioural Ecology Group, Wageningen University & Research (WUR), Wageningen, the Netherlands
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6
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Aubry LM, Williams CT. Vertebrate Phenological Plasticity: from Molecular Mechanisms to Ecological and Evolutionary Implications. Integr Comp Biol 2022; 62:958-971. [PMID: 35867980 DOI: 10.1093/icb/icac121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/28/2022] [Accepted: 04/04/2022] [Indexed: 11/12/2022] Open
Abstract
Seasonal variation in the availability of essential resources is one of the most important drivers of natural selection on the phasing and duration of annually recurring life-cycle events. Shifts in seasonal timing are among the most commonly reported responses to climate change and the capacity of organisms to adjust their timing, either through phenotypic plasticity or evolution, is a critical component of resilience. Despite growing interest in documenting and forecasting the impacts of climate change on phenology, our ability to predict how individuals, populations, and species might alter their seasonal timing in response to their changing environments is constrained by limited knowledge regarding the cues animals use to adjust timing, the endogenous genetic and molecular mechanisms that transduce cues into neural and endocrine signals, and the inherent capacity of animals to alter their timing and phasing within annual cycles. Further, the fitness consequences of phenological responses are often due to biotic interactions within and across trophic levels, rather than being simple outcomes of responses to changes in the abiotic environment. Here, we review the current state of knowledge regarding the mechanisms that control seasonal timing in vertebrates, as well as the ecological and evolutionary consequences of individual, population, and species-level variation in phenological responsiveness. Understanding the causes and consequences of climate-driven phenological shifts requires combining ecological, evolutionary, and mechanistic approaches at individual, populational, and community scales. Thus, to make progress in forecasting phenological responses and demographic consequences, we need to further develop interdisciplinary networks focused on climate change science.
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Affiliation(s)
- Lise M Aubry
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, 1474 Campus Delivery, Fort Collins, CO, 80523, USA
| | - Cory T Williams
- Department of Biology, Colorado State University, 1878 Campus Delivery Fort Collins, CO 80523, USA
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7
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Harper JM, Holmes DJ. New Perspectives on Avian Models for Studies of Basic Aging Processes. Biomedicines 2021; 9:biomedicines9060649. [PMID: 34200297 PMCID: PMC8230007 DOI: 10.3390/biomedicines9060649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/28/2021] [Accepted: 05/29/2021] [Indexed: 12/18/2022] Open
Abstract
Avian models have the potential to elucidate basic cellular and molecular mechanisms underlying the slow aging rates and exceptional longevity typical of this group of vertebrates. To date, most studies of avian aging have focused on relatively few of the phenomena now thought to be intrinsic to the aging process, but primarily on responses to oxidative stress and telomere dynamics. But a variety of whole-animal and cell-based approaches to avian aging and stress resistance have been developed-especially the use of primary cell lines and isolated erythrocytes-which permit other processes to be investigated. In this review, we highlight newer studies using these approaches. We also discuss recent research on age-related changes in neural function in birds in the context of sensory changes relevant to homing and navigation, as well as the maintenance of song. More recently, with the advent of "-omic" methodologies, including whole-genome studies, new approaches have gained momentum for investigating the mechanistic basis of aging in birds. Overall, current research suggests that birds exhibit an enhanced resistance to the detrimental effects of oxidative damage and maintain higher than expected levels of cellular function as they age. There is also evidence that genetic signatures associated with cellular defenses, as well as metabolic and immune function, are enhanced in birds but data are still lacking relative to that available from more conventional model organisms. We are optimistic that continued development of avian models in geroscience, especially under controlled laboratory conditions, will provide novel insights into the exceptional longevity of this animal taxon.
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Affiliation(s)
- James M. Harper
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX 77341, USA
- Correspondence: ; Tel.: +1-936-294-1543
| | - Donna J. Holmes
- Department of Biological Sciences and WWAMI Medical Education Program, University of Idaho, Moscow, ID 83844, USA;
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8
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McNew SM, Boquete MT, Espinoza‐Ulloa S, Andres JA, Wagemaker NCAM, Knutie SA, Richards CL, Clayton DH. Epigenetic effects of parasites and pesticides on captive and wild nestling birds. Ecol Evol 2021; 11:7713-7729. [PMID: 34188846 PMCID: PMC8216931 DOI: 10.1002/ece3.7606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 12/12/2022] Open
Abstract
Anthropogenic changes to the environment challenge animal populations to adapt to new conditions and unique threats. While the study of adaptation has focused on genetic variation, epigenetic mechanisms may also be important. DNA methylation is sensitive to environmental stressors, such as parasites and pesticides, which may affect gene expression and phenotype. We studied the effects of an invasive ectoparasite, Philornis downsi, on DNA methylation of Galápagos mockingbirds (Mimus parvulus). We used the insecticide permethrin to manipulate P. downsi presence in nests of free-living mockingbirds and tested for effects of parasitism on nestling mockingbirds using epiGBS, a reduced-representation bisulfite sequencing (RRBS) approach. To distinguish the confounding effects of insecticide exposure, we conducted a matching experiment exposing captive nestling zebra finches (Taeniopygia guttata) to permethrin. We used zebra finches because they were the closest model organism to mockingbirds that we could breed in controlled conditions. We identified a limited number of differentially methylated cytosines (DMCs) in parasitized versus nonparasitized mockingbirds, but the number was not more than expected by chance. In contrast, we saw clear effects of permethrin on methylation in captive zebra finches. DMCs in zebra finches paralleled documented effects of permethrin exposure on vertebrate cellular signaling and endocrine function. Our results from captive birds indicate a role for epigenetic processes in mediating sublethal nontarget effects of pyrethroid exposure in vertebrates. Environmental conditions in the field were more variable than the laboratory, which may have made effects of both parasitism and permethrin harder to detect in mockingbirds. RRBS approaches such as epiGBS may be a cost-effective way to characterize genome-wide methylation profiles. However, our results indicate that ecological epigenetic studies in natural populations should consider the number of cytosines interrogated and the depth of sequencing in order to have adequate power to detect small and variable effects.
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Affiliation(s)
- Sabrina M. McNew
- School of Biological SciencesUniversity of UtahSalt Lake CityUTUSA
- Cornell Lab of OrnithologyCornell UniversityIthacaNYUSA
- Department of Ecology and Evolutionary BiologyCornell UniversityIthacaNYUSA
| | - M. Teresa Boquete
- Department of Integrative BiologyUniversity of South FloridaTampaFLUSA
- Department of Evolutionary EcologyEstación Biológica de DoñanaCSICSevillaSpain
| | - Sebastian Espinoza‐Ulloa
- Department of BiologyUniversity of SaskatchewanSaskatoonSKCanada
- Facultad de MedicinaPontifica Universidad Católica del EcuadorQuitoEcuador
| | - Jose A. Andres
- Department of Ecology and Evolutionary BiologyCornell UniversityIthacaNYUSA
- Department of BiologyUniversity of SaskatchewanSaskatoonSKCanada
| | | | - Sarah A. Knutie
- School of Biological SciencesUniversity of UtahSalt Lake CityUTUSA
- Department of Ecology and Evolutionary BiologyUniversity of ConnecticutStorrsCTUSA
- Institute for Systems GenomicsUniversity of ConnecticutStorrsCTUSA
| | | | - Dale H. Clayton
- School of Biological SciencesUniversity of UtahSalt Lake CityUTUSA
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9
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Lindner M, Laine VN, Verhagen I, Viitaniemi HM, Visser ME, van Oers K, Husby A. Rapid changes in DNA methylation associated with the initiation of reproduction in a small songbird. Mol Ecol 2021; 30:3645-3659. [PMID: 33453134 PMCID: PMC8359384 DOI: 10.1111/mec.15803] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 12/06/2020] [Accepted: 01/07/2021] [Indexed: 12/12/2022]
Abstract
Species with a circannual life cycle need to match the timing of their life history events to the environment to maximize fitness. However, our understanding of how circannual traits such as timing of reproduction are regulated on a molecular level remains limited. Recent studies have implicated that epigenetic mechanisms can be an important part in the processes that regulate circannual traits. Here, we explore the role of DNA methylation in mediating reproductive timing in a seasonally breeding bird species, the great tit (Parus major), using genome‐wide DNA methylation data from individual females that were blood sampled repeatedly throughout the breeding season. We demonstrate rapid and directional changes in DNA methylation within the promoter region of several genes, including a key transcription factor (NR5A1) known from earlier studies to be involved in the initiation of timing of reproduction. Interestingly, the observed changes in DNA methylation at NR5A1 identified here are in line with earlier gene expression studies of reproduction in chicken, indicating that the observed shifts in DNA methylation at this gene can have a regulatory role. Our findings provide an important step towards elucidating the genomic mechanism that mediates seasonal timing of a key life history traits and provide support for the idea that epigenetic mechanisms may play an important role in circannual traits. see also the Perspective by Melanie J. Heckwolf and Britta S. Meyer
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Affiliation(s)
- Melanie Lindner
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.,Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Veronika N Laine
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.,Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - Irene Verhagen
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Heidi M Viitaniemi
- Organismal and Evolutionary Biology Research Programme (OEB), University of Helsinki, Helsinki, Finland
| | - Marcel E Visser
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.,Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Kees van Oers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Arild Husby
- Organismal and Evolutionary Biology Research Programme (OEB), University of Helsinki, Helsinki, Finland.,Centre for Biodiversity Dynamics, NTNU, Trondheim, Norway.,Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
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10
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Lindner M, Verhagen I, Viitaniemi HM, Laine VN, Visser ME, Husby A, van Oers K. Temporal changes in DNA methylation and RNA expression in a small song bird: within- and between-tissue comparisons. BMC Genomics 2021; 22:36. [PMID: 33413102 PMCID: PMC7792223 DOI: 10.1186/s12864-020-07329-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/15/2020] [Indexed: 12/25/2022] Open
Abstract
Background DNA methylation is likely a key mechanism regulating changes in gene transcription in traits that show temporal fluctuations in response to environmental conditions. To understand the transcriptional role of DNA methylation we need simultaneous within-individual assessment of methylation changes and gene expression changes over time. Within-individual repeated sampling of tissues, which are essential for trait expression is, however, unfeasible (e.g. specific brain regions, liver and ovary for reproductive timing). Here, we explore to what extend between-individual changes in DNA methylation in a tissue accessible for repeated sampling (red blood cells (RBCs)) reflect such patterns in a tissue unavailable for repeated sampling (liver) and how these DNA methylation patterns are associated with gene expression in such inaccessible tissues (hypothalamus, ovary and liver). For this, 18 great tit (Parus major) females were sacrificed at three time points (n = 6 per time point) throughout the pre-laying and egg-laying period and their blood, hypothalamus, ovary and liver were sampled. Results We simultaneously assessed DNA methylation changes (via reduced representation bisulfite sequencing) and changes in gene expression (via RNA-seq and qPCR) over time. In general, we found a positive correlation between changes in CpG site methylation in RBCs and liver across timepoints. For CpG sites in close proximity to the transcription start site, an increase in RBC methylation over time was associated with a decrease in the expression of the associated gene in the ovary. In contrast, no such association with gene expression was found for CpG site methylation within the gene body or the 10 kb up- and downstream regions adjacent to the gene body. Conclusion Temporal changes in DNA methylation are largely tissue-general, indicating that changes in RBC methylation can reflect changes in DNA methylation in other, often less accessible, tissues such as the liver in our case. However, associations between temporal changes in DNA methylation with changes in gene expression are mostly tissue- and genomic location-dependent. The observation that temporal changes in DNA methylation within RBCs can relate to changes in gene expression in less accessible tissues is important for a better understanding of how environmental conditions shape traits that temporally change in expression in wild populations. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-020-07329-9.
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Affiliation(s)
- Melanie Lindner
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, Wageningen, 6700, AB, The Netherlands. .,Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands.
| | - Irene Verhagen
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, Wageningen, 6700, AB, The Netherlands.,Wageningen University & Research, Wageningen, The Netherlands
| | - Heidi M Viitaniemi
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland.,Institute of Vertebrate Biology, Czech Academy of Sciences, Prague, Czech Republic.,Department of Biology, University of Turku, Turku, Finland
| | - Veronika N Laine
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, Wageningen, 6700, AB, The Netherlands.,Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - Marcel E Visser
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, Wageningen, 6700, AB, The Netherlands.,Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Arild Husby
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland.,Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.,Department of Biology, NTNU, Centre for Biodiversity Dynamics, Trondheim, Norway
| | - Kees van Oers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, Wageningen, 6700, AB, The Netherlands.
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11
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Husby A. On the Use of Blood Samples for Measuring DNA Methylation in Ecological Epigenetic Studies. Integr Comp Biol 2020; 60:1558-1566. [PMID: 32835371 PMCID: PMC7742428 DOI: 10.1093/icb/icaa123] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
There is increasing interest in understanding the potential for epigenetic factors to contribute to phenotypic diversity in evolutionary biology. One well studied epigenetic mechanism is DNA methylation, the addition of a methyl group to cytosines, which have the potential to alter gene expression depending on the genomic region in which it takes place. Obtaining information about DNA methylation at genome-wide scale has become straightforward with the use of bisulfite treatment in combination with reduced representation or whole-genome sequencing. While it is well recognized that methylation is tissue specific, a frequent limitation for many studies is that sampling-specific tissues may require sacrificing individuals, something which is generally undesirable and sometimes impossible. Instead, information about DNA methylation patterns in the blood is frequently used as a proxy tissue. This can obviously be problematic if methylation patterns in the blood do not reflect that in the relevant tissue. Understanding how, or if, DNA methylation in blood reflect DNA methylation patterns in other tissues is therefore of utmost importance if we are to make inferences about how observed differences in methylation or temporal changes in methylation can contribute to phenotypic variation. The aim of this review is to examine what we know about the potential for using blood samples in ecological epigenetic studies. I briefly outline some methods by which we can measure DNA methylation before I examine studies that have compared DNA methylation patterns across different tissues and, finally, examine how useful blood samples may be for ecological studies of DNA methylation. Ecological epigenetic studies are in their infancy, but it is paramount for the field to move forward to have detailed information about tissue and time dependence relationships in methylation to gain insights into if blood DNA methylation patterns can be a reliable bioindicator for changes in methylation that generate phenotypic variation in ecologically important traits.
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Affiliation(s)
- Arild Husby
- Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, SE-75236 Uppsala, Sweden
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12
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van Oers K, Sepers B, Sies W, Gawehns F, Verhoeven KJF, Laine VN. Epigenetics of Animal Personality: DNA Methylation Cannot Explain the Heritability of Exploratory Behavior in a Songbird. Integr Comp Biol 2020; 60:1517-1530. [PMID: 33031487 PMCID: PMC7742756 DOI: 10.1093/icb/icaa138] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The search for the hereditary mechanisms underlying quantitative traits traditionally focused on the identification of underlying genomic polymorphisms such as single-nucleotide polymorphisms. It has now become clear that epigenetic mechanisms, such as DNA methylation, can consistently alter gene expression over multiple generations. It is unclear, however, if and how DNA methylation can stably be transferred from one generation to the next and can thereby be a component of the heritable variation of a trait. In this study, we explore whether DNA methylation responds to phenotypic selection using whole-genome and genome-wide bisulfite approaches. We assessed differential erythrocyte DNA methylation patterns between extreme personality types in the Great Tit (Parus major). For this, we used individuals from a four-generation artificial bi-directional selection experiment and siblings from eight F2 inter-cross families. We find no differentially methylated sites when comparing the selected personality lines, providing no evidence for the so-called epialleles associated with exploratory behavior. Using a pair-wise sibling design in the F2 intercrosses, we show that the genome-wide DNA methylation profiles of individuals are mainly explained by family structure, indicating that the majority of variation in DNA methylation in CpG sites between individuals can be explained by genetic differences. Although we found some candidates explaining behavioral differences between F2 siblings, we could not confirm this with a whole-genome approach, thereby confirming the absence of epialleles in these F2 intercrosses. We conclude that while epigenetic variation may underlie phenotypic variation in behavioral traits, we were not able to find evidence that DNA methylation can explain heritable variation in personality traits in Great Tits.
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Affiliation(s)
- Kees van Oers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands.,Behavioural Ecology Group, Wageningen University & Research, Wageningen, P.O. Box 338, 6700 AH, the Netherlands
| | - Bernice Sepers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands.,Behavioural Ecology Group, Wageningen University & Research, Wageningen, P.O. Box 338, 6700 AH, the Netherlands
| | - William Sies
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands
| | - Fleur Gawehns
- Bioinformatics Unit, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands
| | - Koen J F Verhoeven
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands
| | - Veronika N Laine
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands
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13
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Verhagen I, Laine VN, Mateman AC, Pijl A, de Wit R, van Lith B, Kamphuis W, Viitaniemi HM, Williams TD, Caro SP, Meddle SL, Gienapp P, van Oers K, Visser ME. Fine-tuning of seasonal timing of breeding is regulated downstream in the underlying neuro-endocrine system in a small songbird. ACTA ACUST UNITED AC 2019; 222:jeb.202481. [PMID: 31371403 DOI: 10.1242/jeb.202481] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 07/31/2019] [Indexed: 12/15/2022]
Abstract
The timing of breeding is under selection in wild populations as a result of climate change, and understanding the underlying physiological processes mediating this timing provides insight into the potential rate of adaptation. Current knowledge on this variation in physiology is, however, mostly limited to males. We assessed whether individual differences in the timing of breeding in females are reflected in differences in candidate gene expression and, if so, whether these differences occur in the upstream (hypothalamus) or downstream (ovary and liver) parts of the neuroendocrine system. We used 72 female great tits from two generations of lines artificially selected for early and late egg laying, which were housed in climate-controlled aviaries and went through two breeding cycles within 1 year. In the first breeding season we obtained individual egg-laying dates, while in the second breeding season, using the same individuals, we sampled several tissues at three time points based on the timing of the first breeding attempt. For each tissue, mRNA expression levels were measured using qPCR for a set of candidate genes associated with the timing of reproduction and subsequently analysed for differences between generations, time points and individual timing of breeding. We found differences in gene expression between generations in all tissues, with the most pronounced differences in the hypothalamus. Differences between time points, and early- and late-laying females, were found exclusively in the ovary and liver. Altogether, we show that fine-tuning of the seasonal timing of breeding, and thereby the opportunity for adaptation in the neuroendocrine system, is regulated mostly downstream in the neuro-endocrine system.
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Affiliation(s)
- Irene Verhagen
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands
| | - Veronika N Laine
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands
| | - A Christa Mateman
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands
| | - Agata Pijl
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands
| | - Ruben de Wit
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands
| | - Bart van Lith
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands
| | - Willem Kamphuis
- Netherlands Institute for Neuroscience (NIN-KNAW), 1105 BA Amsterdam-Zuidoost, The Netherlands
| | - Heidi M Viitaniemi
- Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
| | - Tony D Williams
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - Samuel P Caro
- Departement d'Ecologie Evolutive, Centre d'Ecologie Fonctionnelle & Evolutive, 34293 Montpellier 5, France
| | - Simone L Meddle
- Department of Behavioural Neuroendocrinology, University of Edinburgh, Edinburgh EH8 9YL, UK
| | - Phillip Gienapp
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands
| | - Kees van Oers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands
| | - Marcel E Visser
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands
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14
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Laine VN, Verhagen I, Mateman AC, Pijl A, Williams TD, Gienapp P, van Oers K, Visser ME. Exploration of tissue-specific gene expression patterns underlying timing of breeding in contrasting temperature environments in a song bird. BMC Genomics 2019; 20:693. [PMID: 31477015 PMCID: PMC6720064 DOI: 10.1186/s12864-019-6043-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 08/19/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Seasonal timing of breeding is a life history trait with major fitness consequences but the genetic basis of the physiological mechanism underlying it, and how gene expression is affected by date and temperature, is not well known. In order to study this, we measured patterns of gene expression over different time points in three different tissues of the hypothalamic-pituitary-gonadal-liver axis, and investigated specifically how temperature affects this axis during breeding. We studied female great tits (Parus major) from lines artificially selected for early and late timing of breeding that were housed in two contrasting temperature environments in climate-controlled aviaries. We collected hypothalamus, liver and ovary samples at three different time points (before and after onset of egg-laying). For each tissue, we sequenced whole transcriptomes of 12 pools (n = 3 females) to analyse gene expression. RESULTS Birds from the selection lines differed in expression especially for one gene with clear reproductive functions, zona pellucida glycoprotein 4 (ZP4), which has also been shown to be under selection in these lines. Genes were differentially expressed at different time points in all tissues and most of the differentially expressed genes between the two temperature treatments were found in the liver. We identified a set of hub genes from all the tissues which showed high association to hormonal functions, suggesting that they have a core function in timing of breeding. We also found ample differentially expressed genes with largely unknown functions in birds. CONCLUSIONS We found differentially expressed genes associated with selection line and temperature treatment. Interestingly, the latter mainly in the liver suggesting that temperature effects on egg-laying date may happen down-stream in the physiological pathway. These findings, as well as our datasets, will further the knowledge of the mechanisms of tissue-specific avian seasonality in the future.
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Affiliation(s)
- Veronika N. Laine
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, The Netherlands
| | - Irene Verhagen
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, The Netherlands
| | - A. Christa Mateman
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, The Netherlands
| | - Agata Pijl
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, The Netherlands
| | - Tony D. Williams
- Department of Biological Sciences, Simon Fraser University, Burnaby, Canada
| | - Phillip Gienapp
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, The Netherlands
| | - Kees van Oers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, The Netherlands
| | - Marcel E. Visser
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, The Netherlands
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15
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Verhagen I, Gienapp P, Laine VN, Grevenhof EM, Mateman AC, Oers K, Visser ME. Genetic and phenotypic responses to genomic selection for timing of breeding in a wild songbird. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13360] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Irene Verhagen
- Department of Animal Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Wageningen The Netherlands
| | - Phillip Gienapp
- Department of Animal Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Wageningen The Netherlands
| | - Veronika N. Laine
- Department of Animal Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Wageningen The Netherlands
| | - Elizabeth M. Grevenhof
- Department of Animal Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Wageningen The Netherlands
| | - Andrea C. Mateman
- Department of Animal Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Wageningen The Netherlands
| | - Kees Oers
- Department of Animal Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Wageningen The Netherlands
| | - Marcel E. Visser
- Department of Animal Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Wageningen The Netherlands
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