1
|
Vlček J, Miláček M, Vinkler M, Štefka J. Effect of population size and selection on Toll-like receptor diversity in populations of Galápagos mockingbirds. J Evol Biol 2023; 36:109-120. [PMID: 36398499 DOI: 10.1111/jeb.14121] [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: 12/09/2021] [Revised: 08/25/2022] [Accepted: 09/10/2022] [Indexed: 11/19/2022]
Abstract
The interactions of evolutionary forces are difficult to analyse in free-living populations. However, when properly understood, they provide valuable insights into evolutionary biology and conservation genetics. This is particularly important for the interplay of genetic drift and natural selection in immune genes that confer resistance to disease. The Galápagos Islands are inhabited by four closely related species of mockingbirds (Mimus spp.). We used 12 different-sized populations of Galápagos mockingbirds and one population of their continental relative northern mockingbird (Mimus polyglottos) to study the effects of genetic drift on the molecular evolution of immune genes, the Toll-like receptors (TLRs: TLR1B, TLR4 and TLR15). We found that neutral genetic diversity was positively correlated with island size, indicating an important effect of genetic drift. However, for TLR1B and TLR4, there was little correlation between functional (e.g., protein) diversity and island size, and protein structural properties were largely conserved, indicating only a limited effect of genetic drift on molecular phenotype. By contrast, TLR15 was less conserved and even its putative functional polymorphism correlated with island size. The patterns observed for the three genes suggest that genetic drift does not necessarily dominate selection even in relatively small populations, but that the final outcome depends on the degree of selection constraint that is specific for each TLR locus.
Collapse
Affiliation(s)
- Jakub Vlček
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic.,Department of Zoology, University of South Bohemia in České Budějovice Faculty of Science, České Budějovice, Czech Republic.,Department of Botany, Charles University Faculty of Science, Prague, Czech Republic
| | - Matěj Miláček
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic.,Department of Zoology, University of South Bohemia in České Budějovice Faculty of Science, České Budějovice, Czech Republic
| | - Michal Vinkler
- Department of Zoology, Charles University Faculty of Science, Prague, Czech Republic
| | - Jan Štefka
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic.,Department of Zoology, University of South Bohemia in České Budějovice Faculty of Science, České Budějovice, Czech Republic
| |
Collapse
|
2
|
Perez G. Role of bank vole (Myodes glareolus) personality on tick burden (Ixodes spp.). Folia Parasitol (Praha) 2022; 69. [DOI: 10.14411/fp.2022.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 02/11/2022] [Indexed: 11/19/2022]
|
3
|
Krasnov BR, Shenbrot GI, Khokhlova IS. Dark diversity of flea assemblages of small mammalian hosts: effects of environment, host traits and host phylogeny. Int J Parasitol 2021; 52:157-167. [PMID: 34560075 DOI: 10.1016/j.ijpara.2021.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/18/2021] [Accepted: 08/19/2021] [Indexed: 11/26/2022]
Abstract
An assemblage of species in a locality comprises two components, namely (i) species that are present (realised diversity) and (ii) species from the regional pool that may potentially inhabit this locality due to suitable ecological conditions, but that are absent (dark diversity). We investigated factors affecting the dark diversity of component communities of fleas parasitic on small mammals in the northern Palearctic at two scales. First, we considered the dark diversity of flea assemblages of the same host (for 13 host species) across regions and tested for the effects of environmental factors and the number of available host species on the dark diversity of within-region flea assemblages. Second, we considered the dark diversity of fleas across host species within a region (for 20 regions) and asked whether within-host dark diversity is associated with host phylogeny and/or traits. We found that the dark diversity of flea assemblages harboured by small mammals varied substantially (i) within the same host species across space (in 12 of 13 host species) and (ii) between host species within a region (in eight of 20 regions). The size of the dark diversity of flea assemblages of the same host across regions was generally affected by environmental factors (mainly by the amount of green vegetation), whereas the size of the dark diversity of flea assemblages of a host species within a region was affected by host traits (mainly by the degree of host sociality and the structure of its shelter and, to a lesser degree, by its geographic range size) but was not associated with host phylogenetic affinities. We conclude that application of the dark diversity concept to parasite communities across space or hosts allows a better understanding of the factors affecting the species richness and composition of these communities.
Collapse
Affiliation(s)
- Boris R Krasnov
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel.
| | - Georgy I Shenbrot
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Irina S Khokhlova
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| |
Collapse
|
4
|
Perrin A, Khimoun A, Faivre B, Ollivier A, de Pracontal N, Théron F, Loubon M, Leblond G, Duron O, Garnier S. Habitat fragmentation differentially shapes neutral and immune gene variation in a tropical bird species. Heredity (Edinb) 2021; 126:148-162. [PMID: 32934360 PMCID: PMC7853120 DOI: 10.1038/s41437-020-00366-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/30/2020] [Accepted: 08/30/2020] [Indexed: 01/11/2023] Open
Abstract
Habitat fragmentation is a major cause of biodiversity loss, responsible for an alteration of intraspecific patterns of neutral genetic diversity and structure. Although neutral genetic variation can be informative for demographic inferences, it may be a poor predictor of adaptive genetic diversity and thus of the consequences of habitat fragmentation on selective evolutionary processes. In this context, we contrasted patterns of genetic diversity and structure of neutral loci (microsatellites) and immune genes (i.e., toll-like receptors) in an understorey bird species, the wedge-billed woodcreeper Glyphorynchus spirurus. The objectives were (1) to investigate forest fragmentation effects on population genetic diversity, (2) to disentangle the relative role of demography (genetic drift and migration) and selection, and (3) to assess whether immunogenetic patterns could be associated with variation of ectoparasite (i.e., ticks) pressures. Our results revealed an erosion of neutral genetic diversity and a substantial genetic differentiation among fragmented populations, resulting from a decrease in landscape connectivity and leading to the divergence of distinct genetic pools at a small spatial scale. Patterns of genetic diversity observed for TLR4 and TLR5 were concordant with neutral genetic patterns, whereas those observed for TLR3 and TLR21 were discordant. This result underlines that the dominant evolutionary force shaping immunogenetic diversity (genetic drift vs. selection) may be different depending on loci considered. Finally, tick prevalence was higher in fragmented environments. We discussed the hypothesis that pathogen selective pressures may contribute to maintain adaptive genetic diversity despite the negative demographic effect of habitat fragmentation on neutral genetic diversity.
Collapse
Affiliation(s)
- Antoine Perrin
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France.
| | - Aurélie Khimoun
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France
| | - Bruno Faivre
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France
| | - Anthony Ollivier
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France
| | - Nyls de Pracontal
- Groupe d'Etude et de Protection des Oiseaux en Guyane, 431 route d'Attila Cabassou, 97354, Rémire-Montjoly, France
| | - Franck Théron
- Groupe d'Etude et de Protection des Oiseaux en Guyane, 431 route d'Attila Cabassou, 97354, Rémire-Montjoly, France
| | - Maxime Loubon
- Groupe d'Etude et de Protection des Oiseaux en Guyane, 431 route d'Attila Cabassou, 97354, Rémire-Montjoly, France
| | - Gilles Leblond
- SARL BIOS, Route de Davidon, Duzer, 97115, Sainte-Rose, France
| | - Olivier Duron
- Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), Centre National de la Recherche Scientifique (CNRS), Institut pour la Recherche et le Développement (IRD), Université de Montpellier (UM), Montpellier, France
| | - Stéphane Garnier
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France
| |
Collapse
|
5
|
Tarnowska E, Niedziałkowska M, Stojak J, Jędrzejewska B. Polymorphism of TLR2 in bank vole populations in North Eastern Poland is not associated with Borrelia afzelii infection prevalence. MAMMAL RES 2020. [DOI: 10.1007/s13364-020-00518-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AbstractPolymorphism in innate immune genes in host populations can structure spatial variation in the prevalence of infectious diseases. In Europe, Borrelia afzelii is an important tick-borne pathogen of small mammals including the bank voles (Myodes glareolus). The Toll-like receptor 2 (TLR2) is an innate immune receptor that is important for detecting Borrelia burgdorferi sensu lato pathogens. The TLR2 gene is polymorphic in bank vole populations and is classified into four distinct clusters: C1, C2, C3, and C4. The C2 and C4 clusters versus the C1 and C3 clusters are associated with lower versus higher infection prevalence, respectively. We detected three TLR2 clusters in 487 bank voles from 30 populations in NE Poland: 84.2% of the obtained sequences belonged to the C1 variant, 7.2% to C2, and 8.6% to C3. However, no clear spatial structure of TLR2 clusters among the populations was detected. B. afzelii infection prevalence across all studied individuals was 12.1% and varied from 0 to 37.5% among populations. There were no significant differences in B. afzelii prevalence among voles carrying alleles of different TLR2 clusters, or between individuals belonging to two mtDNA lineages. Most infected individuals were adults, and males were infected more often than females. There was no significant relationship between the prevalence of TLR2 clusters in the vole populations and climatic and environmental factors within the study area. We therefore could not confirm an adaptive role of the TLR2 C2 alleles in reducing B. afzelii infection prevalence in bank voles.
Collapse
|
6
|
Cornetti L, Tschirren B. Combining genome-wide association study and F ST -based approaches to identify targets of Borrelia-mediated selection in natural rodent hosts. Mol Ecol 2020; 29:1386-1397. [PMID: 32163646 DOI: 10.1111/mec.15410] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 03/02/2020] [Accepted: 03/09/2020] [Indexed: 12/21/2022]
Abstract
Recent advances in high-throughput sequencing technologies provide opportunities to gain novel insights into the genetic basis of phenotypic trait variation. Yet to date, progress in our understanding of genotype-phenotype associations in nonmodel organisms in general and natural vertebrate populations in particular has been hampered by small sample sizes typically available for wildlife populations and a resulting lack of statistical power, as well as a limited ability to control for false-positive signals. Here we propose to combine a genome-wide association study (GWAS) and FST -based approach with population-level replication to partly overcome these limitations. We present a case study in which we used this approach in combination with genotyping-by-sequencing (GBS) single nucleotide polymorphism (SNP) data to identify genomic regions associated with Borrelia afzelii resistance or susceptibility in the natural rodent host of this Lyme disease-causing spirochete, the bank vole (Myodes glareolus). Using this combined approach we identified four consensus SNPs located in exonic regions of the genes Slc26a4, Tns3, Wscd1 and Espnl, which were significantly associated with the voles' Borrelia infectious status within and across populations. Functional links between host responses to bacterial infections and most of these genes have previously been demonstrated in other rodent systems, making them promising new candidates for the study of evolutionary host responses to Borrelia emergence. Our approach is applicable to other systems and may facilitate the identification of genetic variants underlying disease resistance or susceptibility, as well as other ecologically relevant traits, in wildlife populations.
Collapse
Affiliation(s)
- Luca Cornetti
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Zoological Institute, University of Basel, Basel, Switzerland
| | - Barbara Tschirren
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| |
Collapse
|
7
|
Merrill L, Stewart Merrill TE, Barger AM, Benson TJ. Avian Health across the Landscape: Nestling Immunity Covaries with Changing Landcover. Integr Comp Biol 2020; 59:1150-1164. [PMID: 31086961 DOI: 10.1093/icb/icz037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The landscape composition of an organism's home range or territory should influence aspects of its condition, including measures of immune function. Changes in immunocompetence arising from variation in landcover may provide important links between habitat changes and patterns of disease spread. To establish a baseline understanding for whether immune measures covary with changes in landcover, we examined associations between immunological parameters and landcover composition for adults and nestlings of five shrubland bird species. Specifically, we examined the bacteria-killing ability (BKA) of the blood plasma and profiles of the five avian leukocytes as our measures of immune function, and assessed the proportion of area around each bird's nest that was composed of the four major landcover types in the Midwestern USA: row crop agriculture, developed, forest, and grass/shrub. We performed landcover assessments at 100 and 1000 m radius buffers to identify whether associations between habitat and immune function differed at the two spatial scales. As part of this work, we examined age and species-related immunological variation, as well as associations among the immune parameters. There was little evidence linking variation in immune function to landcover composition for the adults at either spatial scale, but there were numerous associations for nestlings, and these were stronger at the 1000 than 100 m spatial scale. The proportion of grass/shrub around the nest had the largest impact on immune function, although the effect varied by immune parameter and species. BKA and basophils were inversely associated with grass/shrub for all species, whereas lymphocytes were positively associated with grass/shrub for all species. We also documented species-level differences among adults and nestlings for BKA and all leukocytes except monocytes. As expected, we found that nestlings had reduced levels of BKA, lymphocytes, monocytes, and elevated heterophils compared with adults (except for field sparrow-Spizella pusilla-nestlings, which had higher lymphocytes). Basophils generally did not differ by age class, and eosinophils exhibited species-specific patterns, in which they were higher for nestling American robins (Turdus migratorius) and gray catbirds (Dumetella carolinensis) compared with adults, but lower in the other nestlings. Heterophils and lymphocytes were inversely associated for all species and age classes, and basophil levels were positively associated with BKA across species and age classes. Together, these findings bolster our understanding of age and species-specific variation in immune function, and provide evidence that immune measures can covary with changes in landcover.
Collapse
Affiliation(s)
- L Merrill
- Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana-Champaign, 61801, USA
| | - T E Stewart Merrill
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois, Urbana-Champaign, 61801, USA
| | - A M Barger
- College of Veterinary Medicine, University of Illinois, Urbana-Champaign, 61802, USA
| | - T J Benson
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois, Urbana-Champaign, 61820, USA
| |
Collapse
|
8
|
Becker DJ, Nachtmann C, Argibay HD, Botto G, Escalera-Zamudio M, Carrera JE, Tello C, Winiarski E, Greenwood AD, Méndez-Ojeda ML, Loza-Rubio E, Lavergne A, de Thoisy B, Czirják GÁ, Plowright RK, Altizer S, Streicker DG. Leukocyte Profiles Reflect Geographic Range Limits in a Widespread Neotropical Bat. Integr Comp Biol 2020; 59:1176-1189. [PMID: 30873523 PMCID: PMC6907035 DOI: 10.1093/icb/icz007] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Quantifying how the environment shapes host immune defense is important for understanding which wild populations may be more susceptible or resistant to pathogens. Spatial variation in parasite risk, food and predator abundance, and abiotic conditions can each affect immunity, and these factors can also manifest at both local and biogeographic scales. Yet identifying predictors and the spatial scale of their effects is limited by the rarity of studies that measure immunity across many populations of broadly distributed species. We analyzed leukocyte profiles from 39 wild populations of the common vampire bat (Desmodus rotundus) across its wide geographic range throughout the Neotropics. White blood cell differentials varied spatially, with proportions of neutrophils and lymphocytes varying up to six-fold across sites. Leukocyte profiles were spatially autocorrelated at small and very large distances, suggesting that local environment and large-scale biogeographic factors influence cellular immunity. Generalized additive models showed that bat populations closer to the northern and southern limits of the species range had more neutrophils, monocytes, and basophils, but fewer lymphocytes and eosinophils, than bats sampled at the core of their distribution. Habitats with access to more livestock also showed similar patterns in leukocyte profiles, but large-scale patterns were partly confounded by time between capture and sampling across sites. Our findings suggest that populations at the edge of their range experience physiologically limiting conditions that predict higher chronic stress and greater investment in cellular innate immunity. High food abundance in livestock-dense habitats may exacerbate such conditions by increasing bat density or diet homogenization, although future spatially and temporally coordinated field studies with common protocols are needed to limit sampling artifacts. Systematically assessing immune function and response over space will elucidate how environmental conditions influence traits relevant to epidemiology and help predict disease risks with anthropogenic disturbance, land conversion, and climate change.
Collapse
Affiliation(s)
- Daniel J Becker
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA.,Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA 30602, USA.,Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Cecilia Nachtmann
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Hernan D Argibay
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Germán Botto
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59715, USA.,Departamento de Metodos Cuantitativos, Facultad de Medicina, Universidad de la República, Montevideo 11800, Uruguay
| | - Marina Escalera-Zamudio
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin 10315, Germany.,Department of Zoology, University of Oxford, Oxford OX1 3SY, UK
| | - Jorge E Carrera
- Facultad de Ciencias, Universidad Nacional de Piura, Piura 20009, Peru.,Programa de Conservación de Murciélagos de Perú, Piura Lima-1, Peru
| | - Carlos Tello
- Association for the Conservation and Development of Natural Resources, Lima 15037, Peru.,Yunkawasi, Lima 15049, Peru
| | - Erik Winiarski
- Departamento de Histología, Facultad de Medicina, Universidad de la República, Montevideo 11800, Uruguay
| | - Alex D Greenwood
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin 10315, Germany.,Department of Veterinary Medicine, Freie Universität Berlin, Berlin 14163, Germany
| | - Maria L Méndez-Ojeda
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Veracruzana, Veracruz 91710, Mexico
| | - Elizabeth Loza-Rubio
- Centro Nacional de Investigación Disciplinaria en Microbiología Animal, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Mexico City 05110, Mexico
| | - Anne Lavergne
- Laboratoire des Interactions Virus-Hôtes, Institut Pasteur de la Guyane, Cayenne, French Guiana F-97300, France
| | - Benoit de Thoisy
- Laboratoire des Interactions Virus-Hôtes, Institut Pasteur de la Guyane, Cayenne, French Guiana F-97300, France
| | - Gábor Á Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin 10315, Germany
| | - Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59715, USA
| | - Sonia Altizer
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA.,Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA 30602, USA
| | - Daniel G Streicker
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA.,Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.,MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| |
Collapse
|
9
|
Becker DJ, Albery GF, Kessler MK, Lunn TJ, Falvo CA, Czirják GÁ, Martin LB, Plowright RK. Macroimmunology: The drivers and consequences of spatial patterns in wildlife immune defence. J Anim Ecol 2020; 89:972-995. [PMID: 31856309 DOI: 10.1111/1365-2656.13166] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 11/06/2019] [Indexed: 01/26/2023]
Abstract
The prevalence and intensity of parasites in wild hosts varies across space and is a key determinant of infection risk in humans, domestic animals and threatened wildlife. Because the immune system serves as the primary barrier to infection, replication and transmission following exposure, we here consider the environmental drivers of immunity. Spatial variation in parasite pressure, abiotic and biotic conditions, and anthropogenic factors can all shape immunity across spatial scales. Identifying the most important spatial drivers of immunity could help pre-empt infectious disease risks, especially in the context of how large-scale factors such as urbanization affect defence by changing environmental conditions. We provide a synthesis of how to apply macroecological approaches to the study of ecoimmunology (i.e. macroimmunology). We first review spatial factors that could generate spatial variation in defence, highlighting the need for large-scale studies that can differentiate competing environmental predictors of immunity and detailing contexts where this approach might be favoured over small-scale experimental studies. We next conduct a systematic review of the literature to assess the frequency of spatial studies and to classify them according to taxa, immune measures, spatial replication and extent, and statistical methods. We review 210 ecoimmunology studies sampling multiple host populations. We show that whereas spatial approaches are relatively common, spatial replication is generally low and unlikely to provide sufficient environmental variation or power to differentiate competing spatial hypotheses. We also highlight statistical biases in macroimmunology, in that few studies characterize and account for spatial dependence statistically, potentially affecting inferences for the relationships between environmental conditions and immune defence. We use these findings to describe tools from geostatistics and spatial modelling that can improve inference about the associations between environmental and immunological variation. In particular, we emphasize exploratory tools that can guide spatial sampling and highlight the need for greater use of mixed-effects models that account for spatial variability while also allowing researchers to account for both individual- and habitat-level covariates. We finally discuss future research priorities for macroimmunology, including focusing on latitudinal gradients, range expansions and urbanization as being especially amenable to large-scale spatial approaches. Methodologically, we highlight critical opportunities posed by assessing spatial variation in host tolerance, using metagenomics to quantify spatial variation in parasite pressure, coupling large-scale field studies with small-scale field experiments and longitudinal approaches, and applying statistical tools from macroecology and meta-analysis to identify generalizable spatial patterns. Such work will facilitate scaling ecoimmunology from individual- to habitat-level insights about the drivers of immune defence and help predict where environmental change may most alter infectious disease risk.
Collapse
Affiliation(s)
- Daniel J Becker
- Department of Biology, Indiana University, Bloomington, IN, USA.,Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA, USA
| | - Gregory F Albery
- Department of Biology, Georgetown University, Washington, DC, USA
| | | | - Tamika J Lunn
- Environmental Futures Research Institute, Griffith University, Nathan, Queensland, Australia
| | - Caylee A Falvo
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | - Gábor Á Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Lynn B Martin
- Department of Global and Planetary Health, University of South Florida, Tampa, FL, USA
| | - Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| |
Collapse
|
10
|
Gomez-Chamorro A, Battilotti F, Cayol C, Mappes T, Koskela E, Boulanger N, Genné D, Sarr A, Voordouw MJ. Susceptibility to infection with Borrelia afzelii and TLR2 polymorphism in a wild reservoir host. Sci Rep 2019; 9:6711. [PMID: 31040326 PMCID: PMC6491475 DOI: 10.1038/s41598-019-43160-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 04/17/2019] [Indexed: 12/14/2022] Open
Abstract
The study of polymorphic immune genes in host populations is critical for understanding genetic variation in susceptibility to pathogens. Controlled infection experiments are necessary to separate variation in the probability of exposure from genetic variation in susceptibility to infection, but such experiments are rare for wild vertebrate reservoir hosts and their zoonotic pathogens. The bank vole (Myodes glareolus) is an important reservoir host of Borrelia afzelii, a tick-borne spirochete that causes Lyme disease. Bank vole populations are polymorphic for Toll-like receptor 2 (TLR2), an innate immune receptor that recognizes bacterial lipoproteins. To test whether the TLR2 polymorphism influences variation in the susceptibility to infection with B. afzelii, we challenged pathogen-free, lab-born individuals of known TLR2 genotype with B. afzelii-infected ticks. We measured the spirochete load in tissues of the bank voles. The susceptibility to infection with B. afzelii following an infected tick bite was very high (95%) and did not differ between TLR2 genotypes. The TLR2 polymorphism also had no effect on the spirochete abundance in the tissues of the bank voles. Under the laboratory conditions of our study, we did not find that the TLR2 polymorphism in bank voles influenced variation in the susceptibility to B. afzelii infection.
Collapse
Affiliation(s)
| | | | - Claire Cayol
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Tapio Mappes
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Esa Koskela
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Nathalie Boulanger
- Facultés de Médecine et de Pharmacie, Université de Strasbourg, Strasbourg, France
| | - Dolores Genné
- Institut de Biologie, Université de Neuchâtel, Neuchâtel, Switzerland
| | - Anouk Sarr
- Institut de Biologie, Université de Neuchâtel, Neuchâtel, Switzerland
| | - Maarten Jeroen Voordouw
- Institut de Biologie, Université de Neuchâtel, Neuchâtel, Switzerland.
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
| |
Collapse
|
11
|
Cornetti L, Hilfiker D, Lemoine M, Tschirren B. Small-scale spatial variation in infection risk shapes the evolution of a Borrelia resistance gene in wild rodents. Mol Ecol 2018; 27:3515-3524. [PMID: 30040159 DOI: 10.1111/mec.14812] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 07/04/2018] [Accepted: 07/10/2018] [Indexed: 12/19/2022]
Abstract
Spatial variation in pathogen-mediated selection is predicted to influence the evolutionary trajectory of host populations and lead to spatial variation in their immunogenetic composition. However, to date few studies have been able to directly link small-scale spatial variation in infection risk to host immune gene evolution in natural, nonhuman populations. Here, we use a natural rodent-Borrelia system to test for associations between landscape-level spatial variation in Borrelia infection risk along replicated elevational gradients in the Swiss Alps and Toll-like receptor 2 (TLR2) evolution, a candidate gene for Borrelia resistance, across bank vole (Myodes glareolus) populations. We found that Borrelia infection risk (i.e., the product of Borrelia prevalence in questing ticks and the average tick load of voles at a sampling site) was spatially variable and significantly negatively associated with elevation. Across sampling sites, Borrelia prevalence in bank voles was significantly positively associated with Borrelia infection risk along the elevational clines. We observed a significant association between naturally occurring TLR2 polymorphisms in hosts and their Borrelia infection status. The TLR2 variant associated with a reduced likelihood of Borrelia infection was most common in rodent populations at lower elevations that face a high Borrelia infection risk, and its frequency changed in accordance with the change in Borrelia infection risk along the elevational clines. These results suggest that small-scale spatial variation in parasite-mediated selection affects the immunogenetic composition of natural host populations, providing a striking example that the microbial environment shapes the evolution of the host's immune system in the wild.
Collapse
Affiliation(s)
- Luca Cornetti
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Zoological Institute, University of Basel, Basel, Switzerland
| | - Daniela Hilfiker
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Mélissa Lemoine
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Barbara Tschirren
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| |
Collapse
|
12
|
Cayol C, Giermek A, Gomez-Chamorro A, Hytönen J, Kallio ER, Mappes T, Salo J, Voordouw MJ, Koskela E. Borrelia afzelii alters reproductive success in a rodent host. Proc Biol Sci 2018; 285:20181056. [PMID: 30068677 PMCID: PMC6111163 DOI: 10.1098/rspb.2018.1056] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/09/2018] [Indexed: 02/07/2023] Open
Abstract
The impact of a pathogen on the fitness and behaviour of its natural host depends upon the host-parasite relationship in a given set of environmental conditions. Here, we experimentally investigated the effects of Borrelia afzelii, one of the aetiological agents of Lyme disease in humans, on the fitness of its natural rodent host, the bank vole (Myodes glareolus), in semi-natural conditions with two contrasting host population densities. Our results show that B. afzelii can modify the reproductive success and spacing behaviour of its rodent host, whereas host survival was not affected. Infection impaired the breeding probability of large bank voles. Reproduction was hastened in infected females without alteration of the offspring size at birth. At low density, infected males produced fewer offspring, fertilized fewer females and had lower mobility than uninfected individuals. Meanwhile, the infection did not affect the proportion of offspring produced or the proportion of mating partner in female bank voles. Our study is the first to show that B. afzelii infection alters the reproductive success of the natural host. The effects observed could reflect the sickness behaviour due to the infection or they could be a consequence of a manipulation of the host behaviour by the bacteria.
Collapse
Affiliation(s)
- Claire Cayol
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, 40014, Jyväskylä, Finland
| | - Anna Giermek
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Cracow, Poland
| | - Andrea Gomez-Chamorro
- Institut de Biologie, Laboratoire d'Ecologie et Evolution des Parasites, Université de Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
| | - Jukka Hytönen
- Institute of Biomedicine, University of Turku, Kiinamyllynkatu 13, 20520, Turku, Finland
| | - Eva Riikka Kallio
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, 40014, Jyväskylä, Finland
- Department of Ecology and Genetics, University of Oulu, PO Box 3000, 90014, Oulu, Finland
| | - Tapio Mappes
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, 40014, Jyväskylä, Finland
| | - Jemiina Salo
- Institute of Biomedicine, University of Turku, Kiinamyllynkatu 13, 20520, Turku, Finland
| | - Maarten Jeroen Voordouw
- Institut de Biologie, Laboratoire d'Ecologie et Evolution des Parasites, Université de Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
| | - Esa Koskela
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, 40014, Jyväskylä, Finland
| |
Collapse
|
13
|
Whiteoak AM, Ideozu J, Alkathiry H, Tomlinson AJ, Delahay RJ, Cowen S, Mullineaux E, Gormley E, Birtles RJ, Lun ZR, Hide G. Investigation into the genetic diversity in toll-like receptors 2 and 4 in the European badger Meles meles. Res Vet Sci 2018; 119:228-231. [PMID: 30005397 DOI: 10.1016/j.rvsc.2018.06.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 05/23/2018] [Accepted: 06/28/2018] [Indexed: 01/14/2023]
Abstract
The Toll-like receptor (TLR) genes are a conserved family of genes central to the innate immune response to pathogen infection. They encode receptor proteins, recognise pathogen associated molecular patterns (PAMPs) and trigger initial immune responses. In some host-pathogen systems, it is reported that genetic differences, such as single nucleotide polymorphisms (SNPs), associate with disease resistance or susceptibility. Little is known about TLR gene diversity in the European badger (Meles meles). We collected DNA from UK badgers, carried out PCR amplification of the badger TLR2 gene and exon 3 of TLR4 and determined DNA sequences for individual badgers for TLR2 (n = 61) and TLR4 exon 3 (n = 59). No polymorphism was observed in TLR4. Three TLR2 amino acid haplotype variants were found. Ninety five percent of badgers were homozygous for one common haplotype (H1), the remaining three badgers had genotypes H1/H3, H1/H2 and H2/H2. By broad comparison with other species, diversity in TLR genes in badgers seems low. This could be due to a relatively localised sampling or inherent low genetic diversity. Further studies are required to assess the generality of the low observed diversity and the relevance to the immunological status of badgers.
Collapse
Affiliation(s)
- Andrew M Whiteoak
- Ecosystems and Environment Research Centre, School of Environment and Life Sciences, University of Salford, M5 4WT, UK
| | - Justin Ideozu
- Ecosystems and Environment Research Centre, School of Environment and Life Sciences, University of Salford, M5 4WT, UK
| | - Hadil Alkathiry
- Ecosystems and Environment Research Centre, School of Environment and Life Sciences, University of Salford, M5 4WT, UK
| | - Alexandra J Tomlinson
- National Wildlife Management Centre, Animal and Plant Health Agency, Woodchester Park, Gloucestershire GL10 3UJ, UK
| | - Richard J Delahay
- National Wildlife Management Centre, Animal and Plant Health Agency, Woodchester Park, Gloucestershire GL10 3UJ, UK
| | - Sara Cowen
- Secret World Wildlife Rescue, New Road, East Huntspill, Highbridge TA9 3PZ, UK
| | | | - Eamonn Gormley
- School of Veterinary Medicine, Veterinary Science Centre, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | - Richard J Birtles
- Ecosystems and Environment Research Centre, School of Environment and Life Sciences, University of Salford, M5 4WT, UK
| | - Zhao-Rong Lun
- Ecosystems and Environment Research Centre, School of Environment and Life Sciences, University of Salford, M5 4WT, UK; State Key Laboratory of Biocontrol, School of Life Sciences, Key Laboratory of Tropical Diseases and Control of the Ministry of Education, Zhongshan Medical School, Sun Yat-Sen University, Guangzhou 510275, PR China; Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, M5 4WT, UK
| | - Geoff Hide
- Ecosystems and Environment Research Centre, School of Environment and Life Sciences, University of Salford, M5 4WT, UK; Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, M5 4WT, UK.
| |
Collapse
|
14
|
McKnight DT, Schwarzkopf L, Alford RA, Bower DS, Zenger KR. Effects of emerging infectious diseases on host population genetics: a review. CONSERV GENET 2017. [DOI: 10.1007/s10592-017-0974-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
15
|
Blanchong JA, Robinson SJ, Samuel MD, Foster JT. Application of genetics and genomics to wildlife epidemiology. J Wildl Manage 2016. [DOI: 10.1002/jwmg.1064] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Julie A. Blanchong
- Department of Natural Resource Ecology and Management; Iowa State University; 339 Science II Ames IA 50011 USA
| | | | - Michael D. Samuel
- U.S. Geological Survey, Wisconsin Cooperative Wildlife Research Unit; University of Wisconsin; 204 Russell Labs, 1630 Linden Dr. Madison WI 53706 USA
| | - Jeffrey T. Foster
- Department of Molecular, Cellular and Biomedical Sciences; University of New Hampshire; 291 Rudman Hall Durham NH 03824 USA
| |
Collapse
|