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Rivero de Aguilar J, Barroso O, Bonaccorso E, Cadena H, Hussing L, Jorquera J, Martinez J, Martínez‐de la Puente J, Marzal A, León Miranda F, Merino S, Matta NE, Ramenofsky M, Rozzi R, Valeris‐Chacín CE, Vásquez RA, Vianna JA, Wingfield JC. Associations among MHC genes, latitude, and avian malaria infections in the rufous-collared sparrow ( Zonotrichia capensis). Ecol Evol 2024; 14:e11634. [PMID: 39026957 PMCID: PMC11255377 DOI: 10.1002/ece3.11634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Accepted: 06/12/2024] [Indexed: 07/20/2024] Open
Abstract
The major histocompatibility complex (MHC) is a genetic region in jawed vertebrates that contains key genes involved in the immune response. Associations between the MHC and avian malaria infections in wild birds have been observed and mainly explored in the Northern Hemisphere, while a general lack of information remains in the Southern Hemisphere. Here, we investigated the associations between the MHC genes and infections with Plasmodium and Haemoproteus blood parasites along a latitudinal gradient in South America. We sampled 93 rufous-collared sparrows (Zonotrichia capensis) individuals from four countries, Colombia, Ecuador, Peru, and Chile, and estimated MHC-I and MHC-II allele diversity. We detected between 1-4 (MHC-I) and 1-6 (MHC-II) amino acidic alleles per individual, with signs of positive selection. We obtained generalized additive mixed models to explore the associations between MHC-I and MHC-II diversity and latitude. We also explored the relationship between infection status and latitude/biome. We found a non-linear association between the MHC-II amino acidic allele diversity and latitude. Individuals from north Chile presented a lower MHC genetic diversity than those from other locations. We also found an association between deserts and xeric shrublands and a lower prevalence of Haemoproteus parasites. Our results support a lower MHC genetic in arid or semi-arid habitats in the region with the lower prevalence of Haemoproteus parasites.
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Affiliation(s)
- Juan Rivero de Aguilar
- Centro Subantártico Cabo de Hornos (CHIC)Universidad de MagallanesPuerto WilliamsChile
- Departamento de Ciencias Ecológicas, Facultad de CienciasUniversidad de ChileSantiagoChile
- Instituto de Ecología y Biodiversidad, Facultad de CienciasUniversidad de ChileSantiagoChile
| | - Omar Barroso
- Centro Subantártico Cabo de Hornos (CHIC)Universidad de MagallanesPuerto WilliamsChile
| | - Elisa Bonaccorso
- Laboratorio de Biología Evolutiva, and Instituto Biósfera, Colegio de Ciencias Biológicas y AmbientalesUniversidad San Francisco de QuitoQuitoEcuador
- Centro de la Biodiversidad y Cambio ClimáticoUniversidad Tecnológica IndoaméricaQuitoEcuador
| | - Hector Cadena
- Centro de la Biodiversidad y Cambio ClimáticoUniversidad Tecnológica IndoaméricaQuitoEcuador
| | - Lucas Hussing
- Departamento de Ciencias Ecológicas, Facultad de CienciasUniversidad de ChileSantiagoChile
| | - Josefina Jorquera
- Departamento de Ecología, Instituto Para el Desarrollo Sustentable, Facultad de Ciencias BiológicasPontificia Universidad Católica de ChileSantiagoChile
| | - Javier Martinez
- Departamento de Biomedicina y Biotecnología (Area de Parasitología)Universidad de Alcalá de HenaresMadridSpain
| | - Josué Martínez‐de la Puente
- Departamento de ParasitologíaUniversidad de GranadaGranadaSpain
- Ciber de Epidemiología y Salud Pública (CIBERESP)MadridSpain
| | - Alfonso Marzal
- Departamento de Anatomía, Biología Celular y Zoología, Facultad de BiologíaUniversidad de ExtremaduraBadajozSpain
- Grupo de Investigaciones en Fauna SilvestreUniversidad Nacional de San MartínTarapotoPeru
| | - Fabiola León Miranda
- Departamento de Ecología, Instituto Para el Desarrollo Sustentable, Facultad de Ciencias BiológicasPontificia Universidad Católica de ChileSantiagoChile
| | - Santiago Merino
- Departamento de Ecología EvolutivaMuseo Nacional de Ciencias Naturales CSICMadridSpain
| | - Nubia E. Matta
- Departamento de Biología, Facultad de CienciasUniversidad Nacional de ColombiaBogotáColombia
| | - Marilyn Ramenofsky
- Department of Neurobiology, Physiology and BehaviorUniversity of CaliforniaDavisCaliforniaUSA
| | - Ricardo Rozzi
- Centro Subantártico Cabo de Hornos (CHIC)Universidad de MagallanesPuerto WilliamsChile
| | - Carlos E. Valeris‐Chacín
- Centro Subantártico Cabo de Hornos (CHIC)Universidad de MagallanesPuerto WilliamsChile
- Departamento de Ciencias Ecológicas, Facultad de CienciasUniversidad de ChileSantiagoChile
| | - Rodrigo A. Vásquez
- Centro Subantártico Cabo de Hornos (CHIC)Universidad de MagallanesPuerto WilliamsChile
- Departamento de Ciencias Ecológicas, Facultad de CienciasUniversidad de ChileSantiagoChile
- Instituto de Ecología y Biodiversidad, Facultad de CienciasUniversidad de ChileSantiagoChile
| | - Juliana A. Vianna
- Departamento de Ecología, Instituto Para el Desarrollo Sustentable, Facultad de Ciencias BiológicasPontificia Universidad Católica de ChileSantiagoChile
- Millennium Institute Center for Genome Regulation (CRG)Millennium Institute of Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Millennium Nucleus of Patagonian Limit of Life (LiLi)SantiagoChile
| | - John C. Wingfield
- Department of Neurobiology, Physiology and BehaviorUniversity of CaliforniaDavisCaliforniaUSA
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2
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Evaluation of Genetic Diversity and Parasite-Mediated Selection of MHC Class I Genes in Emberiza godlewskii (Passeriformes: Emberizidae). DIVERSITY 2022. [DOI: 10.3390/d14110925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The major histocompatibility complex (MHC) is a multi-copy immune gene family in vertebrates. Its genes are highly variable and code for antigen-presenting molecules. Characterization of MHC genes in different species and investigating the mechanisms that shape MHC diversity is an important goal in understanding the evolution of biological diversity. Here we developed a next-generation sequencing (NGS) protocol to genotype the MHC class I genes of 326 Godlewski’s buntings (Emberiza godlewskii) sampled in the Western mountain area of Beijing from 2014 to 2016. A total of 184 functional alleles were identified, including both non-classical and classical alleles, clustering into nine supertypes. Compared with other passerine birds, the number of MHC class I alleles per individual in Godlewski’s buntings is high (mean 16.1 ± 3.3, median 16). In addition, we demonstrated signatures of historical and contemporary selection on MHC genes. Reflecting historical selection, ten amino acid sites in the antigen-binding domain showed signatures of balancing selection, eight of which exhibit high amino acid polymorphism. In terms of contemporary selection, we found that specific MHC supertypes were nominally associated with the infection of two malaria parasite lineages. These findings indicate the action of historical and possibly also contemporary balancing selection and suggest negative frequency-dependent or fluctuating selection as possible selection mechanisms.
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3
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Migalska M, Przesmycka K, Alsarraf M, Bajer A, Behnke-Borowczyk J, Grzybek M, Behnke JM, Radwan J. Long term patterns of association between MHC and helminth burdens in the bank vole support Red Queen dynamics. Mol Ecol 2022; 31:3400-3415. [PMID: 35510766 PMCID: PMC9325469 DOI: 10.1111/mec.16486] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/28/2022] [Accepted: 04/04/2022] [Indexed: 11/28/2022]
Abstract
Major histocompatibility complex (MHC) genes encode proteins crucial for adaptive immunity of vertebrates. Negative frequency-dependent selection (NFDS), resulting from adaptation of parasites to common MHC types, has been hypothesized to maintain high, functionally relevant polymorphism of MHC, but demonstration of this relationship has remained elusive. In particular, differentiation of NFDS from fluctuating selection, resulting from changes in parasite communities in time and space (FS), has proved difficult in short-term studies. Here, we used temporal data, accumulated through long-term monitoring of helminths infecting bank voles (Myodes glareolus), to test specific predictions of NFDS on MHC class II. Data were collected in three, moderately genetically differentiated subpopulations in Poland, which were characterized by some stable spatiotemporal helminth communities but also events indicating introduction of new species and loss of others. We found a complex association between individual MHC diversity and species richness, where intermediate numbers of DRB supertypes correlated with lowest species richness, but the opposite was true for DQB supertypes - arguing against universal selection for immunogenetic optimality. We also showed that particular MHC supertypes explain a portion of the variance in prevalence and abundance of helminths, but this effect was subpopulation-specific, which is consistent with both NFDS and FS. Finally, in line with NFDS, we found that certain helminths that have recently colonized or spread in a given subpopulation, more frequently or intensely infected voles with MHC supertypes that have been common in the recent past. Overall, our results highlight complex spatial and temporal patterns of MHC-parasite associations, the latter being consistent with Red Queen coevolutionary dynamics.
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Affiliation(s)
- Magdalena Migalska
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland
| | - Karolina Przesmycka
- Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland
| | - Mohammed Alsarraf
- Department of Eco-epidemiology of Parasitic Diseases, Institute of Developmental Biology and Biomedical Sciences, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Anna Bajer
- Department of Eco-epidemiology of Parasitic Diseases, Institute of Developmental Biology and Biomedical Sciences, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Jolanta Behnke-Borowczyk
- Department of Forest Entomology and Pathology, Faculty of Forestry and Wood Technology, Poznań University of Life Sciences, Wojska Polskiego 71c, 60-625, Poznań, Poland
| | - Maciej Grzybek
- Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Powstania Styczniowego 9B, 81-429, Gdynia, Poland
| | - Jerzy M Behnke
- School of Life Science, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Jacek Radwan
- Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland
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Qin S, Dunn PO, Yang Y, Liu H, He K. Polymorphism and varying selection within the MHC class I of four Anas species. Immunogenetics 2021; 73:395-404. [PMID: 34195858 DOI: 10.1007/s00251-021-01222-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 06/23/2021] [Indexed: 10/21/2022]
Abstract
Ducks (Anatidae) are often vectors for the spread of pathogens because of their long-distance migrations. These migrations also expose ducks to a wide variety of pathogens in their wintering and breeding grounds, and, as a consequence, we might expect strong selection on their immune genes. Here, we studied exons 2 and 3 of the MHC class I in four species of Anas ducks (A. platyrhynchos, A. poecilorhyncha, A. formosa, and A. querquedula) using Illumina-sequencing. Both exons 2 and 3 code for the peptide-binding region of class I molecules; however, most previous studies of birds have only focused on exon 3. Here, we found stronger positive selection on exon 2 than exon 3, as indicated by more species with dN/dS > 1 and higher Wu-Kabat values. There was little evidence that divergence time influenced polymorphism, the numbers of identical alleles (partial α1 or α2 regions) among four Anas, or selection, suggesting that these widespread species might share similar levels of selection from pathogens. The high similarity of allele numbers, positively selected sites (PSS), conserved motifs, and variable protein sites (VPS) supported the persistence of trans-species polymorphism in Anas for at least 10 million years. Our study revealed exon 2 as a relatively unexplored source of variation in avian MHC class I, which should be considered in future studies.
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Affiliation(s)
- Shidi Qin
- College of Animal Science and Technology, College of Veterinary Medicine, Key Laboratory of Applied Technology On Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Agriculture and Forestry University, Zhejiang Provincial Engineering Laboratory for Animal Health Inspection and Internet Technology, Hangzhou, China
| | - Peter O Dunn
- Behavioral and Molecular Ecology Group, Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, USA
| | - Yang Yang
- College of Animal Science and Technology, College of Veterinary Medicine, Key Laboratory of Applied Technology On Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Agriculture and Forestry University, Zhejiang Provincial Engineering Laboratory for Animal Health Inspection and Internet Technology, Hangzhou, China
| | - Hongyi Liu
- College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, China
| | - Ke He
- College of Animal Science and Technology, College of Veterinary Medicine, Key Laboratory of Applied Technology On Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Agriculture and Forestry University, Zhejiang Provincial Engineering Laboratory for Animal Health Inspection and Internet Technology, Hangzhou, China.
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5
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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.
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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
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6
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Doyle JM, Willoughby JR, Bell DA, Bloom PH, Bragin EA, Fernandez NB, Katzner TE, Leonard K, DeWoody JA. Elevated Heterozygosity in Adults Relative to Juveniles Provides Evidence of Viability Selection on Eagles and Falcons. J Hered 2019; 110:696-706. [DOI: 10.1093/jhered/esz048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 08/01/2019] [Indexed: 02/06/2023] Open
Abstract
AbstractViability selection yields adult populations that are more genetically variable than those of juveniles, producing a positive correlation between heterozygosity and survival. Viability selection could be the result of decreased heterozygosity across many loci in inbred individuals and a subsequent decrease in survivorship resulting from the expression of the deleterious alleles. Alternatively, locus-specific differences in genetic variability between adults and juveniles may be driven by forms of balancing selection, including heterozygote advantage, frequency-dependent selection, or selection across temporal and spatial scales. We use a pooled-sequencing approach to compare genome-wide and locus-specific genetic variability between 74 golden eagle (Aquila chrysaetos), 62 imperial eagle (Aquila heliaca), and 69 prairie falcon (Falco mexicanus) juveniles and adults. Although genome-wide genetic variability is comparable between juvenile and adult golden eagles and prairie falcons, imperial eagle adults are significantly more heterozygous than juveniles. This evidence of viability selection may stem from a relatively smaller imperial eagle effective population size and potentially greater genetic load. We additionally identify ~2000 single-nucleotide polymorphisms across the 3 species with extreme differences in heterozygosity between juveniles and adults. Many of these markers are associated with genes implicated in immune function or olfaction. These loci represent potential targets for studies of how heterozygote advantage, frequency-dependent selection, and selection over spatial and temporal scales influence survivorship in avian species. Overall, our genome-wide data extend previous studies that used allozyme or microsatellite markers and indicate that viability selection may be a more common evolutionary phenomenon than often appreciated.
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Affiliation(s)
- Jacqueline M Doyle
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN
| | - Janna R Willoughby
- School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama
- Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Douglas A Bell
- Department of Biological Sciences, Towson University, Baltimore, MD
- East Bay Regional Park District, Oakland, CA
- Department of Ornithology and Mammalogy, California Academy of Sciences, San Francisco, CA
| | - Peter H Bloom
- Department of Biological Sciences, Towson University, Baltimore, MD
- Bloom Research Inc., Los Angeles, CA
| | - Evgeny A Bragin
- Department of Biological Sciences, Towson University, Baltimore, MD
- Faculty of Natural Science, Kostanay State Pedagogical University, Kostanay, Kazakhstan
- The Peregrine Fund, Boise, ID
- Science Department, Naurzum National Nature Reserve, Kostanay Oblast, Naurzumski Raijon, Karamendy, Kazakhstan
| | - Nadia B Fernandez
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN
- Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, MA
| | - Todd E Katzner
- Department of Biological Sciences, Towson University, Baltimore, MD
- US Geological Survey, Forest and Rangeland Ecosystem Science Center, Boise, ID
| | - Kolbe Leonard
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Computer and Information Sciences, Towson University, Baltimore, MD
| | - J Andrew DeWoody
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN
- Department of Biological Sciences, Purdue University, West Lafayette, IN
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7
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Cassin-Sackett L, Callicrate TE, Fleischer RC. Parallel evolution of gene classes, but not genes: Evidence from Hawai'ian honeycreeper populations exposed to avian malaria. Mol Ecol 2018; 28:568-583. [PMID: 30298567 DOI: 10.1111/mec.14891] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 10/14/2018] [Accepted: 10/19/2018] [Indexed: 12/29/2022]
Abstract
Adaptation in nature is ubiquitous, yet characterizing its genomic basis is difficult because population demographics cause correlations with nonadaptive loci. Introduction events provide opportunities to observe adaptation over known spatial and temporal scales, facilitating the identification of genes involved in adaptation. The pathogen causing avian malaria, Plasmodium relictum, was introduced to Hawai'i in the 1930s and elicited extinctions and precipitous population declines in native honeycreepers. After a sharp initial population decline, the Hawai'i 'amakihi (Chlorodrepanis virens) has evolved tolerance to the parasite at low elevations where P. relictum exists, and can sustain infection without major fitness consequences. High-elevation, unexposed populations of 'amakihi display little to no tolerance. To explore the genomic basis of adaptation to P. relictum in low-elevation 'amakihi, we genotyped 125 'amakihi from the island of Hawai'i via hybridization capture to 40,000 oligonucleotide baits containing SNPs and used the reference 'amakihi genome to identify genes potentially under selection from malaria. We tested for outlier loci between low- and high-elevation population pairs and identified loci with signatures of selection within low-elevation populations. In some cases, genes commonly involved in the immune response (e.g., major histocompatibility complex) were associated with malaria presence in the population. We also detected several novel candidate loci that may be implicated in surviving malaria infection (e.g., beta-defensin, glycoproteins and interleukin-related genes). Our results suggest that rapid adaptation to pathogens may occur through changes in different immune genes, but in the same classes of genes, across populations.
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Affiliation(s)
- Loren Cassin-Sackett
- Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia.,Department of Integrative Biology, University of South Florida, Tampa, Florida
| | - Taylor E Callicrate
- Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia.,Species Conservation Toolkit Initiative, Department of Conservation Science, Chicago Zoological Society, Brookfield, Illinois
| | - Robert C Fleischer
- Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia
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8
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Hacking JD, Stuart‐Fox D, Godfrey SS, Gardner MG. Specific MHC class I supertype associated with parasite infection and color morph in a wild lizard population. Ecol Evol 2018; 8:9920-9933. [PMID: 30386586 PMCID: PMC6202711 DOI: 10.1002/ece3.4479] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 12/30/2022] Open
Abstract
The major histocompatibility complex (MHC) is a large gene family that plays a central role in the immune system of all jawed vertebrates. Nonavian reptiles are underrepresented within the MHC literature and little is understood regarding the mechanisms maintaining MHC diversity in this vertebrate group. Here, we examined the relative roles of parasite-mediated selection and sexual selection in maintaining MHC class I diversity of a color polymorphic lizard. We discovered evidence for parasite-mediated selection acting via rare-allele advantage or fluctuating selection as ectoparasite load was significantly lower in the presence of a specific MHC supertype (functional clustering of alleles): supertype four. Based on comparisons between ectoparasite prevalence and load, and assessment of the impact of ectoparasite load on host fitness, we suggest that supertype four confers quantitative resistance to ticks or an intracellular tickborne parasite. We found no evidence for MHC-associated mating in terms of pair genetic distance, number of alleles, or specific supertypes. An association was uncovered between supertype four and male throat color morph. However, it is unlikely that male throat coloration acts as a signal of MHC genotype to conspecifics because we found no evidence to suggest that male throat coloration predicts male mating status. Overall, our results suggest that parasite-mediated selection plays a role in maintaining MHC diversity in this population via rare-allele advantage and/or fluctuating selection. Further work is required to determine whether sexual selection also plays a role in maintaining MHC diversity in agamid lizards.
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Affiliation(s)
- Jessica D. Hacking
- College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
| | - Devi Stuart‐Fox
- School of BioSciencesUniversity of MelbourneParkvilleVictoriaAustralia
| | | | - Michael G. Gardner
- College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
- Evolutionary Biology UnitSouth Australian MuseumAdelaideSouth AustraliaAustralia
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9
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Whittingham LA, Dunn PO, Freeman-Gallant CR, Taff CC, Johnson JA. Major histocompatibility complex variation and blood parasites in resident and migratory populations of the common yellowthroat. J Evol Biol 2018; 31:1544-1557. [DOI: 10.1111/jeb.13349] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 06/12/2018] [Accepted: 06/25/2018] [Indexed: 01/13/2023]
Affiliation(s)
- Linda A. Whittingham
- Behavioral and Molecular Ecology Group; Department of Biological Sciences; University of Wisconsin-Milwaukee; Milwaukee WI USA
| | - Peter O. Dunn
- Behavioral and Molecular Ecology Group; Department of Biological Sciences; University of Wisconsin-Milwaukee; Milwaukee WI USA
| | | | - Conor C. Taff
- Cornell Laboratory of Ornithology; Cornell University; Ithaca NY USA
| | - Jeff A. Johnson
- Department of Biological Sciences; Institute of Applied Sciences; University of North Texas; Denton TX USA
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10
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Lei W, Zhou X, Fang W, Lin Q, Chen X. Major histocompatibility complex class II DAB alleles associated with intestinal parasite load in the vulnerable Chinese egret (Egretta eulophotes). Ecol Evol 2016; 6:4421-34. [PMID: 27386085 PMCID: PMC4930990 DOI: 10.1002/ece3.2226] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 05/04/2016] [Accepted: 05/16/2016] [Indexed: 11/09/2022] Open
Abstract
The maintenance of major histocompatibility complex (MHC) polymorphism has been hypothesized to result from many mechanisms such as rare-allele advantage, heterozygote advantage, and allele counting. In the study reported herein, 224 vulnerable Chinese egrets (Egretta eulophotes) were used to examine these hypotheses as empirical results derived from bird studies are rare. Parasite survey showed that 147 (65.63%) individuals were infected with 1-3 helminths, and 82.31% of these infected individuals carried Ascaridia sp. Using asymmetric polymerase chain reaction technique, 10 DAB1, twelve DAB2, and three DAB3 exon 2 alleles were identified at each single locus. A significant association of the rare allele Egeu-DAB2*05 (allele frequency: 0.022) with helminth resistance was found for all helminths, as well as for the most abundant morphotype Ascaridia sp. in the separate analyses. Egeu-DAB2*05 occurred frequently in uninfected individuals, and individuals carrying Egeu-DAB2*05 had significantly lower helminth morphotypes per individual (HMI) (the number of HMI) and the fecal egg count values. Further, the parasite infection measurements were consistently lower in individuals with an intermediate number of different alleles in the duplicated DAB loci. Significantly, heterozygosity within each DAB locus was not correlated with any parasite infection measurements. These results indicate that the diversity in MHC Egeu-DAB gene is associated with intestinal parasite load and maintained by pathogen-driven selection that probably operate through both the rare-allele advantage and the allele counting strategy, and suggest that Egeu-DAB2*05 might be a valuable indicator of better resistance to helminth diseases in the vulnerable Chinese egret.
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Affiliation(s)
- Wei Lei
- Key Laboratory of Ministry of Education for Coast and Wetland EcosystemsCollege of the Environment and EcologyXiamen UniversityXiamen361102China
| | - Xiaoping Zhou
- Key Laboratory of Ministry of Education for Coast and Wetland EcosystemsCollege of the Environment and EcologyXiamen UniversityXiamen361102China
| | - Wenzhen Fang
- Key Laboratory of Ministry of Education for Coast and Wetland EcosystemsCollege of the Environment and EcologyXiamen UniversityXiamen361102China
| | - Qingxian Lin
- Key Laboratory of Ministry of Education for Coast and Wetland EcosystemsCollege of the Environment and EcologyXiamen UniversityXiamen361102China
| | - Xiaolin Chen
- Key Laboratory of Ministry of Education for Coast and Wetland EcosystemsCollege of the Environment and EcologyXiamen UniversityXiamen361102China
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