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Cortazar‐Chinarro M, King KC, Lillie M. MHC Diversity Across Time and Space. Ecol Evol 2025; 15:e71371. [PMID: 40297318 PMCID: PMC12034939 DOI: 10.1002/ece3.71371] [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: 04/26/2023] [Revised: 04/07/2025] [Accepted: 04/15/2025] [Indexed: 04/30/2025] Open
Abstract
Most natural populations are genetically diverse. Understanding how diversity is maintained and distributed across time and space can provide insights into the potential for evolution and extinction of populations. Immunogenetic diversity aids individuals and populations in resisting infectious disease, with many studies linking resistance to genes encoding adaptive immune responses, such as the major histocompatibility complex (MHC) genes. The MHC is particularly important for advancing our understanding of local adaptive processes and host-parasite interactions. Here, we review the emerging work and theory exploring the geographic and temporal patterns of MHC diversity in the wild and how they are shaped by selective and demographic processes. We discuss patterns of variation along latitudinal and altitudinal gradients and place this in the context of Latitude Diversity Gradient and Central Marginal Theories. We emphasize how MHC diversity is often lower at the edges of species distributions, particularly in high-latitude and high-altitude regions. We also discuss MHC diversity in natural populations facing climate change. As climate change accelerates and emerging parasites spread, reduced immunogenetic diversity could severely threaten wildlife populations, compromising their resilience and long-term survival. We propose that including immunogenetic diversity into a larger database of environmental and parasite data would allow biologists to test hypotheses regarding host-parasite coevolution and develop effective measures for conservation.
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Affiliation(s)
- Maria Cortazar‐Chinarro
- MEMEG/Department of BiologyFaculty of Science, Lund UniversityLundSweden
- Department of Earth Ocean and Atmospheric SciencesUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of Ecology and Genetics, Animal EcologyUppsala UniversityUppsalaSweden
| | - Kayla C. King
- Department of ZoologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of Microbiology & ImmunologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of BiologyUniversity of OxfordOxfordUK
| | - Mette Lillie
- Department of Ecology and Genetics, Animal EcologyUppsala UniversityUppsalaSweden
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2
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Yan J, Song C, Liang J, La Y, Lai J, Pan R, Huang Z, Li B, Zhang P. Moderate Genetic Diversity of MHC Genes in an Isolated Small Population of Black-and-White Snub-Nosed Monkeys ( Rhinopithecus bieti). Animals (Basel) 2024; 14:2276. [PMID: 39123802 PMCID: PMC11310952 DOI: 10.3390/ani14152276] [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: 06/11/2024] [Revised: 08/01/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024] Open
Abstract
Genetic diversity is an essential indicator that echoes the natural selection and environmental adaptation of a species. Isolated small populations are vulnerable to genetic drift, inbreeding, and limited gene flow; thus, assessing their genetic diversity is critical in conservation. In this study, we studied the genetic diversity of black-and-white snub-nosed monkeys (Rhinopithecus bieti) using neutral microsatellites and five adaptive major histocompatibility complex (MHC) genes. Two DQA1 alleles, two DQB1 alleles, two DRB1 alleles, two DRB5 alleles, and three DPB1 alleles were isolated from a population. The results indicate that neutral microsatellites demonstrate a high degree of heterozygosity and polymorphism, while adaptive MHC genes display a high degree of heterozygosity and moderate polymorphism. The results also show that balancing selection has prominently influenced the MHC diversity of the species during evolution: (1) significant positive selection is identified at several amino acid sites (primarily at and near antigen-binding sites) of the DRB1, DRB5, and DQB1 genes; (2) phylogenetic analyses display the patterns of trans-species evolution for all MHC loci. This study provides valuable genetic diversity insights into black-and-white snub-nosed monkeys, which dwell at the highest altitude and have experienced the harshest environmental selection of all primates globally since the Pleistocene. Such results provide valuable scientific evidence and a reference for making or amending conservation strategies for this endangered primate species.
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Affiliation(s)
- Jibing Yan
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
| | - Chunmei Song
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
| | - Jiaqi Liang
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
| | - Yanni La
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
| | - Jiandong Lai
- Baima Snow Mountain National Nature Reserve Administrative Bureau, Diqing 674500, China;
| | - Ruliang Pan
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
- International Center of Biodiversity and Primat Conservation, Dali University, Dali 671003, China
- School of Human Sciences, The University of Western Australia, Perth, WA 6009, Australia
| | - Zhipang Huang
- Institute of Eastern-Himalaya Biodiversity Research, Dali University, Dali 671003, China;
| | - Baoguo Li
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
- Shaanxi Institute of Zoology, Xi’an 710032, China
- College of Life Science, Yanan University, Yanan 710032, China
| | - Pei Zhang
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
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3
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Liu P, Li G, Zhao N, Song X, Wang J, Shi X, Wang B, Zhang L, Dong L, Li Q, Liu Q, Lu L. Neutral Forces and Balancing Selection Interplay to Shape the Major Histocompatibility Complex Spatial Patterns in the Striped Hamster in Inner Mongolia: Suggestive of Broad-Scale Local Adaptation. Genes (Basel) 2023; 14:1500. [PMID: 37510404 PMCID: PMC10379431 DOI: 10.3390/genes14071500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/20/2023] [Accepted: 07/21/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND The major histocompatibility complex (MHC) plays a key role in the adaptive immune response to pathogens due to its extraordinary polymorphism. However, the spatial patterns of MHC variation in the striped hamster remain unclear, particularly regarding the relative contribution of the balancing selection in shaping MHC spatial variation and diversity compared to neutral forces. METHODS In this study, we investigated the immunogenic variation of the striped hamster in four wild populations in Inner Mongolia which experience a heterogeneous parasitic burden. Our goal was to identify local adaptation by comparing the genetic structure at the MHC with that at seven microsatellite loci, taking into account neutral processes. RESULTS We observed significant variation in parasite pressure among sites, with parasite burden showing a correlation with temperature and precipitation. Molecular analysis revealed a similar co-structure between MHC and microsatellite loci. We observed lower genetic differentiation at MHC loci compared to microsatellite loci, and no correlation was found between the two. CONCLUSIONS Overall, these results suggest a complex interplay between neutral evolutionary forces and balancing selection in shaping the spatial patterns of MHC variation. Local adaptation was not detected on a small scale but may be applicable on a larger scale.
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Affiliation(s)
- Pengbo Liu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Guichang Li
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Ning Zhao
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Xiuping Song
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Jun Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Xinfei Shi
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Bin Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Public Health School, Jiamusi University, Jiamusi 154007, China
| | - Lu Zhang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Li Dong
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Qingduo Li
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Qiyong Liu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Liang Lu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
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Lam DK, Frantz AC, Burke T, Geffen E, Sin SYW. Both selection and drift drive the spatial pattern of adaptive genetic variation in a wild mammal. Evolution 2023; 77:221-238. [PMID: 36626810 DOI: 10.1093/evolut/qpac014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 10/03/2022] [Accepted: 11/04/2022] [Indexed: 01/12/2023]
Abstract
The major histocompatibility complex (MHC) has been intensively studied for the relative effects of different evolutionary forces in recent decades. Pathogen-mediated balancing selection is generally thought to explain the high polymorphism observed in MHC genes, but it is still unclear to what extent MHC diversity is shaped by selection relative to neutral drift. In this study, we genotyped MHC class II DRB genes and 15 neutral microsatellite loci across 26 geographic populations of European badgers (Meles meles) covering most of their geographic range. By comparing variation of microsatellite and diversity of MHC at different levels, we demonstrate that both balancing selection and drift have shaped the evolution of MHC genes. When only MHC allelic identity was investigated, the spatial pattern of MHC variation was similar to that of microsatellites. By contrast, when functional aspects of the MHC diversity (e.g., immunological supertypes) were considered, balancing selection appears to decrease genetic structuring across populations. Our comprehensive sampling and analytical approach enable us to conclude that the likely mechanisms of selection are heterozygote advantage and/or rare-allele advantage. This study is a clear demonstration of how both balancing selection and genetic drift simultaneously affect the evolution of MHC genes in a widely distributed wild mammal.
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Affiliation(s)
- Derek Kong Lam
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Alain C Frantz
- Musée National d'Histoire Naturelle, Luxembourg, Luxembourg
| | - Terry Burke
- Ecology and Evolutionary Biology, School of Biosciences, University of Sheffield, Sheffield, United Kingdom
| | - Eli Geffen
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Simon Yung Wa Sin
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
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5
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Wolverines (Gulo gulo) in the Arctic: Revisiting distribution and identifying research and conservation priorities amid rapid environmental change. Polar Biol 2022; 45:1465-1482. [PMID: 36090964 PMCID: PMC9440465 DOI: 10.1007/s00300-022-03079-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 11/23/2022]
Abstract
Wolverines (Gulo gulo) occupy most of the globe’s Arctic tundra. Given the rapidly warming climate and expanding human activity in this biome, understanding wolverine ecology, and therefore the species’ vulnerability to such changes, is increasingly important for developing research priorities and effective management strategies. Here, we review and synthesize knowledge of wolverines in the Arctic using both Western science sources and available Indigenous Knowledge (IK) to improve our understanding of wolverine ecology in the Arctic and better predict the species’ susceptibility to change. To accomplish this, we update the pan-Arctic distribution map of wolverines to account for recent observations and then discuss resulting inference and uncertainties. We use these patterns to contextualize and discuss potential underlying drivers of distribution and population dynamics, drawing upon knowledge of food habits, habitat associations, and harvest, as well as studies of wolverine ecology elsewhere. We then identify four broad areas to prioritize conservation and research efforts: (1) Monitoring trends in population abundance, demographics, and distribution and the drivers thereof, (2) Evaluating and predicting wolverines’ responses to ongoing climate change, particularly the consequences of reduced snow and sea ice, and shifts in prey availability, (3) Understanding wolverines’ response to human development, including the possible impact of wintertime over-snow travel and seismic testing to reproductive denning, as well as vulnerability to hunting and trapping associated with increased human access, and (4) Ensuring that current and future harvest are sustainable.
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6
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Diversity of the MHC class II DRB gene in the wolverine (Carnivora: Mustelidae: Gulo gulo) in Finland. PLoS One 2022; 17:e0267609. [PMID: 35536786 PMCID: PMC9089919 DOI: 10.1371/journal.pone.0267609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 04/08/2022] [Indexed: 11/19/2022] Open
Abstract
The wolverine (Gulo gulo) in Finland has undergone significant population declines in the past. Since major histocompatibility complex (MHC) genes encode proteins involved in pathogen recognition, the diversity of these genes provides insights into the immunological fitness of regional populations. We sequenced 862 amplicons (242 bp) of MHC class II DRB exon 2 from 32 Finnish wolverines and identified 11 functional alleles and three pseudogenes. A molecular phylogenetic analysis indicated trans-species polymorphism, and PAML and MEME analyses indicated positive selection, suggesting that the Finnish wolverine DRB genes have evolved under balancing and positive selection. In contrast to DRB gene analyses in other species, allele frequencies in the Finnish wolverines clearly indicated the existence of two regional subpopulations, congruent with previous studies based on neutral genetic markers. In the Finnish wolverine, rapid population declines in the past have promoted genetic drift, resulting in a lower genetic diversity of DRB loci, including fewer alleles and positively selected sites, than other mustelid species analyzed previously. Our data suggest that the MHC region in the Finnish wolverine population was likely affected by a recent bottleneck.
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7
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Wolverines (Gulo gulo) in a changing landscape and warming climate: A decadal synthesis of global conservation ecology research. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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8
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Surviving despite reduce MHC variation: selection patterns and genetic variation of the endangered Huillín (Lontra provocax). MAMMAL RES 2021. [DOI: 10.1007/s13364-021-00594-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Carroll KA, Inman RM, Hansen AJ, Lawrence RL, Barnett K. A framework for collaborative wolverine connectivity conservation. iScience 2021; 24:102840. [PMID: 34368656 PMCID: PMC8326200 DOI: 10.1016/j.isci.2021.102840] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/04/2021] [Accepted: 07/08/2021] [Indexed: 12/03/2022] Open
Abstract
Maintaining connectivity between high-elevation public lands is important for wolverines and other species of conservation concern. This work represents the first effort to prioritize wolverine connectivity under future climate conditions using a systematic conservation planning framework. We optimized 10, 15, 20, and 50% of habitat features for wolverines using integer linear programming. We identified 369 privately owned areas in the 10% solution, 572 in the 15% solution, 822 in the 20% solution, and 3,996 in the 50% solution where voluntary landowner easements would improve the long-term landscape functionality for wolverine connectivity. The median estimated easements ranged from $8,762 to $12,220 across the four solutions (total costs $14,874,371 to $196,346,714). Overall, this effort demonstrates the utility of optimization problems for conserving connectivity, provides a proactive tool to engage potential collaborators, identifies easements that will likely protect various subalpine species, and offers a framework for the conservation of additional species.
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Affiliation(s)
- Kathleen A. Carroll
- Montana State University, Ecology Department, Montana State University, PO Box 173460, Bozeman, MT 59717, USA
- University of Wisconsin-Madison, Department of Forest and Wildlife Ecology, 1630 Linden Dr, Madison, WI 53706, USA
| | - Robert M. Inman
- Montana Fish, Wildlife and Parks, 1420 E 6th Avenue, Helena, MT 59620, USA
| | - Andrew J. Hansen
- Montana State University, Ecology Department, Montana State University, PO Box 173460, Bozeman, MT 59717, USA
| | - Rick L. Lawrence
- Montana State University, Land Resources and Environmental Sciences Department, 334 Leon Johnson Hall, P.O. Box 173120, Bozeman, MT 59717, USA
| | - Kevin Barnett
- The Wilderness Society, 503 W Mendenhall St, Bozeman, MT 59715, USA
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10
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Bourgeois Y, Fields P, Bento G, Ebert D. Balancing selection for pathogen resistance reveals an intercontinental signature of Red Queen coevolution. Mol Biol Evol 2021; 38:4918-4933. [PMID: 34289047 PMCID: PMC8557431 DOI: 10.1093/molbev/msab217] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The link between long-term host–parasite coevolution and genetic diversity is key to understanding genetic epidemiology and the evolution of resistance. The model of Red Queen host–parasite coevolution posits that high genetic diversity is maintained when rare host resistance variants have a selective advantage, which is believed to be the mechanistic basis for the extraordinarily high levels of diversity at disease-related genes such as the major histocompatibility complex in jawed vertebrates and R-genes in plants. The parasites that drive long-term coevolution are, however, often elusive. Here we present evidence for long-term balancing selection at the phenotypic (variation in resistance) and genomic (resistance locus) level in a particular host–parasite system: the planktonic crustacean Daphnia magna and the bacterium Pasteuria ramosa. The host shows widespread polymorphisms for pathogen resistance regardless of geographic distance, even though there is a clear genome-wide pattern of isolation by distance at other sites. In the genomic region of a previously identified resistance supergene, we observed consistent molecular signals of balancing selection, including higher genetic diversity, older coalescence times, and lower differentiation between populations, which set this region apart from the rest of the genome. We propose that specific long-term coevolution by negative-frequency-dependent selection drives this elevated diversity at the host's resistance loci on an intercontinental scale and provide an example of a direct link between the host’s resistance to a virulent pathogen and the large-scale diversity of its underlying genes.
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Affiliation(s)
- Yann Bourgeois
- University of Basel, Department of Environmental Sciences, Zoology, Vesalgasse 1, 4051 Basel, Switzerland
| | - Peter Fields
- University of Basel, Department of Environmental Sciences, Zoology, Vesalgasse 1, 4051 Basel, Switzerland
| | - Gilberto Bento
- University of Basel, Department of Environmental Sciences, Zoology, Vesalgasse 1, 4051 Basel, Switzerland
| | - Dieter Ebert
- University of Basel, Department of Environmental Sciences, Zoology, Vesalgasse 1, 4051 Basel, Switzerland
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11
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Krejsa DM, Talbot SL, Sage GK, Sonsthagen SA, Jung TS, Magoun AJ, Cook JA. Dynamic landscapes in northwestern North America structured populations of wolverines (Gulo gulo). J Mammal 2021. [DOI: 10.1093/jmammal/gyab045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Cyclic climatic and glacial fluctuations of the Late Quaternary produced a dynamic biogeographic history for high latitudes. To refine our understanding of this history in northwestern North America, we explored geographic structure in a wide-ranging carnivore, the wolverine (Gulo gulo). We examined genetic variation in populations across mainland Alaska, coastal Southeast Alaska, and mainland western Canada using nuclear microsatellite genotypes and sequence data from the mitochondrial DNA (mtDNA) control region and Cytochrome b (Cytb) gene. Data from maternally inherited mtDNA reflect stable populations in Northwest Alaska, suggesting the region harbored wolverine populations since at least the Last Glacial Maximum (LGM; 21 Kya), consistent with their persistence in the fossil record of Beringia. Populations in Southeast Alaska are characterized by minimal divergence, with no genetic signature of long-term refugial persistence (consistent with the lack of pre-Holocene fossil records there). The Kenai Peninsula population exhibits mixed signatures depending on marker type: mtDNA data indicate stability (i.e., historical persistence) and include a private haplotype, whereas biparentally inherited microsatellites exhibit relatively low variation and a lack of private alleles consistent with a more recent Holocene colonization of the peninsula. Our genetic work is largely consistent with the early 20th century taxonomic hypothesis that wolverines on the Kenai Peninsula belong to a distinct subspecies. Our finding of significant genetic differentiation of wolverines inhabiting the Kenai Peninsula, coupled with the peninsula’s burgeoning human population and the wolverine’s known sensitivity to anthropogenic impacts, provides valuable foundational data that can be used to inform conservation and management prescriptions for wolverines inhabiting these landscapes.
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Affiliation(s)
- Dianna M Krejsa
- Department of Biology and Angelo State Natural History Collections, Angelo State University, ASU Station 10890, San Angelo, TX 76909-0890, USA
| | - Sandra L Talbot
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK 99508, USA
| | - George K Sage
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK 99508, USA
| | | | - Thomas S Jung
- Department of Environment, Government of Yukon, Whitehorse, YT, Y1A 2C6, Canada
| | - Audrey J Magoun
- Wildlife Research and Management, 3680 Non Road, Fairbanks, AK 99709, USA
| | - Joseph A Cook
- Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM 87131, USA
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12
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Baecklund TM, Morrison J, Donaldson ME, Hueffer K, Kyle CJ. The role of a mechanistic host in maintaining arctic rabies variant distributions: Assessment of functional genetic diversity in Alaskan red fox (Vulpes vulpes). PLoS One 2021; 16:e0249176. [PMID: 33831031 PMCID: PMC8031376 DOI: 10.1371/journal.pone.0249176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 03/12/2021] [Indexed: 11/18/2022] Open
Abstract
Populations are exposed to different types and strains of pathogens across heterogeneous landscapes, where local interactions between host and pathogen may present reciprocal selective forces leading to correlated patterns of spatial genetic structure. Understanding these coevolutionary patterns provides insight into mechanisms of disease spread and maintenance. Arctic rabies (AR) is a lethal disease with viral variants that occupy distinct geographic distributions across North America and Europe. Red fox (Vulpes vulpes) are a highly susceptible AR host, whose range overlaps both geographically distinct AR strains and regions where AR is absent. It is unclear if genetic structure exists among red fox populations relative to the presence/absence of AR or the spatial distribution of AR variants. Acquiring these data may enhance our understanding of the role of red fox in AR maintenance/spread and inform disease control strategies. Using a genotyping-by-sequencing assay targeting 116 genomic regions of immunogenetic relevance, we screened for sequence variation among red fox populations from Alaska and an outgroup from Ontario, including areas with different AR variants, and regions where the disease was absent. Presumed neutral SNP data from the assay found negligible levels of neutral genetic structure among Alaskan populations. The immunogenetically-associated data identified 30 outlier SNPs supporting weak to moderate genetic structure between regions with and without AR in Alaska. The outliers included SNPs with the potential to cause missense mutations within several toll-like receptor genes that have been associated with AR outcome. In contrast, there was a lack of genetic structure between regions with different AR variants. Combined, we interpret these data to suggest red fox populations respond differently to the presence of AR, but not AR variants. This research increases our understanding of AR dynamics in the Arctic, where host/disease patterns are undergoing flux in a rapidly changing Arctic landscape, including the continued northward expansion of red fox into regions previously predominated by the arctic fox (Vulpes lagopus).
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Affiliation(s)
- Tristan M. Baecklund
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
- * E-mail:
| | - Jaycee Morrison
- Forensic Science Undergraduate Program, Trent University, Peterborough, Ontario, Canada
| | - Michael E. Donaldson
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
| | - Karsten Hueffer
- Department of Veterinary Medicine, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Christopher J. Kyle
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
- Forensic Science Department, Trent University, Peterborough, Ontario, Canada
- Natural Resources DNA Profiling & Forensic Centre, Trent University, Peterborough, Ontario, Canada
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13
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Yi X, Donner DM, Marquardt PE, Palmer JM, Jusino MA, Frair J, Lindner DL, Latch EK. Major histocompatibility complex variation is similar in little brown bats before and after white-nose syndrome outbreak. Ecol Evol 2020; 10:10031-10043. [PMID: 33005361 PMCID: PMC7520216 DOI: 10.1002/ece3.6662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 07/18/2020] [Accepted: 07/19/2020] [Indexed: 12/28/2022] Open
Abstract
White-nose syndrome (WNS), caused by the fungal pathogen Pseudogymnoascus destructans (Pd), has driven alarming declines in North American hibernating bats, such as little brown bat (Myotis lucifugus). During hibernation, infected little brown bats are able to initiate anti-Pd immune responses, indicating pathogen-mediated selection on the major histocompatibility complex (MHC) genes. However, such immune responses may not be protective as they interrupt torpor, elevate energy costs, and potentially lead to higher mortality rates. To assess whether WNS drives selection on MHC genes, we compared the MHC DRB gene in little brown bats pre- (Wisconsin) and post- (Michigan, New York, Vermont, and Pennsylvania) WNS (detection spanning 2014-2015). We genotyped 131 individuals and found 45 nucleotide alleles (27 amino acid alleles) indicating a maximum of 3 loci (1-5 alleles per individual). We observed high allelic admixture and a lack of genetic differentiation both among sampling sites and between pre- and post-WNS populations, indicating no signal of selection on MHC genes. However, post-WNS populations exhibited decreased allelic richness, reflecting effects from bottleneck and drift following rapid population declines. We propose that mechanisms other than adaptive immunity are more likely driving current persistence of little brown bats in affected regions.
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Affiliation(s)
- Xueling Yi
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukeeWIUSA
| | - Deahn M. Donner
- Northern Research StationUSDA Forest ServiceRhinelanderWIUSA
| | | | | | - Michelle A. Jusino
- Northern Research StationUSDA Forest ServiceMadisonWIUSA
- Department of Plant PathologyUniversity of FloridaGainesvilleFLUSA
| | - Jacqueline Frair
- Roosevelt Wild Life StationSUNY College of Environmental Science and ForestrySyracuseNYUSA
| | | | - Emily K. Latch
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukeeWIUSA
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14
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Ebert D, Fields PD. Host-parasite co-evolution and its genomic signature. Nat Rev Genet 2020; 21:754-768. [PMID: 32860017 DOI: 10.1038/s41576-020-0269-1] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2020] [Indexed: 01/14/2023]
Abstract
Studies in diverse biological systems have indicated that host-parasite co-evolution is responsible for the extraordinary genetic diversity seen in some genomic regions, such as major histocompatibility (MHC) genes in jawed vertebrates and resistance genes in plants. This diversity is believed to evolve under balancing selection on hosts by parasites. However, the mechanisms that link the genomic signatures in these regions to the underlying co-evolutionary process are only slowly emerging. We still lack a clear picture of the co-evolutionary concepts and of the genetic basis of the co-evolving phenotypic traits in the interacting antagonists. Emerging genomic tools that provide new options for identifying underlying genes will contribute to a fuller understanding of the co-evolutionary process.
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Affiliation(s)
- Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland. .,Wissenschaftskolleg zu Berlin, Berlin, Germany.
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
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15
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Gagnon M, Yannic G, Boyer F, Côté SD. Adult survival in migratory caribou is negatively associated with MHC functional diversity. Heredity (Edinb) 2020; 125:290-303. [PMID: 32728043 DOI: 10.1038/s41437-020-0347-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 07/04/2020] [Accepted: 07/16/2020] [Indexed: 11/09/2022] Open
Abstract
Genes of the major histocompatibility complex (MHC) are involved in acquired immunity in vertebrates. Only a few studies have investigated the fitness consequences of MHC gene diversity in wild populations. Here, we looked at the association between annual survival and body mass and MHC-DRB exon 2 (MHC-DRB) genetic diversity, obtained from high-throughput sequencing, in two declining migratory caribou (Rangifer tarandus) herds. To disentangle the potential direct and general effects of MHC-DRB genetic diversity, we compared different indices of diversity that were either based on DNA-sequence variation or on physicochemical divergence of the translated peptides, thereby covering a gradient of allelic-to-functional diversity. We found that (1) body mass was not related to MHC-DRB diversity or genotype, and (2) adult survival probability was negatively associated with point accepted mutation distance, a corrected distance that considers the likelihood of each amino acid substitution to be accepted by natural selection. In addition, we found no evidence of fluctuating selection over time on MHC-DRB diversity. We concluded that direct effects were involved in the negative relationship between MHC functional diversity and survival, although the mechanism underlying this result remains unclear. A possible explanation could be that individuals with higher MHC diversity suffer higher costs of immunity (immunopathology). Our results suggest that genetic diversity is not always beneficial even in genes that are likely to be strongly shaped by balancing selection.
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Affiliation(s)
- Marianne Gagnon
- Département de Biologie, Caribou Ungava and Centre d'Études Nordiques, Université Laval, 1045 avenue de la Médecine, Quebec City, QC, G1V 0A6, Canada
| | - Glenn Yannic
- Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS, LECA, 38000, Grenoble, France.
| | - Frédéric Boyer
- Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS, LECA, 38000, Grenoble, France
| | - Steeve D Côté
- Département de Biologie, Caribou Ungava and Centre d'Études Nordiques, Université Laval, 1045 avenue de la Médecine, Quebec City, QC, G1V 0A6, Canada
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16
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Genome-Wide Changes in Genetic Diversity in a Population of Myotis lucifugus Affected by White-Nose Syndrome. G3-GENES GENOMES GENETICS 2020; 10:2007-2020. [PMID: 32276959 PMCID: PMC7263666 DOI: 10.1534/g3.119.400966] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Novel pathogens can cause massive declines in populations, and even extirpation of hosts. But disease can also act as a selective pressure on survivors, driving the evolution of resistance or tolerance. Bat white-nose syndrome (WNS) is a rapidly spreading wildlife disease in North America. The fungus causing the disease invades skin tissues of hibernating bats, resulting in disruption of hibernation behavior, premature energy depletion, and subsequent death. We used whole-genome sequencing to investigate changes in allele frequencies within a population of Myotis lucifugus in eastern North America to search for genetic resistance to WNS. Our results show low FST values within the population across time, i.e., prior to WNS (Pre-WNS) compared to the population that has survived WNS (Post-WNS). However, when dividing the population with a geographical cut-off between the states of Pennsylvania and New York, a sharp increase in values on scaffold GL429776 is evident in the Post-WNS samples. Genes present in the diverged area are associated with thermoregulation and promotion of brown fat production. Thus, although WNS may not have subjected the entire M. lucifugus population to selective pressure, it may have selected for specific alleles in Pennsylvania through decreased gene flow within the population. However, the persistence of remnant sub-populations in the aftermath of WNS is likely due to multiple factors in bat life history.
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17
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Hosotani S, Nishita Y, Masuda R. Genetic diversity and evolution of the MHC class II DRB gene in the Japanese marten, Martes melampus (Carnivora: Mustelidae). MAMMAL RES 2020. [DOI: 10.1007/s13364-020-00506-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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Lansink GMJ, Esparza-Salas R, Joensuu M, Koskela A, Bujnáková D, Kleven O, Flagstad Ø, Ollila T, Kojola I, Aspi J, Kvist L. Population genetics of the wolverine in Finland: the road to recovery? CONSERV GENET 2020. [DOI: 10.1007/s10592-020-01264-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
AbstractAfter decades, even centuries of persecution, large carnivore populations are widely recovering in Europe. Considering the recent recovery of the wolverine (Gulo gulo) in Finland, our aim was to evaluate genetic variation using 14 microsatellites and mtDNA control region (579 bp) in order (1) to determine whether the species is represented by a single genetic population within Finland, (2) to quantify the genetic diversity, and (3) to estimate the effective population size. We found two major genetic clusters divided between eastern and northern Finland based on microsatellites (FST = 0.100) but also a significant pattern of isolation by distance. Wolverines in western Finland had a genetic signature similar to the northern cluster, which can be explained by former translocations of wolverines from northern to western Finland. For both main clusters, most estimates of the effective population size Ne were below 50. Nevertheless, the genetic diversity was higher in the eastern cluster (HE = 0.57, AR = 4.0, AP = 0.3) than in the northern cluster (HE = 0.49, AR = 3.7, AP = 0.1). Migration between the clusters was low. Two mtDNA haplotypes were found: one common and identical to Scandinavian wolverines; the other rare and not previously detected. The rare haplotype was more prominent in the eastern genetic cluster. Combining all available data, we infer that the genetic population structure within Finland is shaped by a recent bottleneck, isolation by distance, human-aided translocations and postglacial recolonization routes.
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19
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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: 11.8] [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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20
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Talarico L, Babik W, Marta S, Pietrocini V, Mattoccia M. MHC structuring and divergent allele advantage in a urodele amphibian: a hierarchical multi-scale approach. Heredity (Edinb) 2019; 123:593-607. [PMID: 31036951 PMCID: PMC6972932 DOI: 10.1038/s41437-019-0221-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/31/2019] [Accepted: 03/31/2019] [Indexed: 12/27/2022] Open
Abstract
Proteins encoded by extraordinarily polymorphic major histocompatibility complex (MHC) genes are involved in the adaptive immune response. Balancing selection is believed to maintain MHC polymorphism in the long term, although neutral processes also play a role in shaping MHC diversity. However, the relative contribution of these processes is poorly understood. Here we characterized MHC class II variation of a low-dispersal, pond-breeding newt (Triturus carnifex) over a restricted, geographically structured area. We aimed to (1) evaluate the contribution of selection and neutral processes to shaping MHC diversity at two geographic scales, and (2) test for signatures of divergent allele advantage (DAA), which is a potentially important mechanism of balancing selection. The dominant role of selection in shaping MHC variation was suggested by the lack of correlation between MHC and neutral (microsatellite) variation. Although most variation occurred within populations for both types of markers, they differed in the extent of structuring at the two spatial scales. MHC structuring was more pronounced at local scales, suggesting the role of local selection, while structuring was not detectable at a larger scale, possibly due to the effect of balancing selection. Microsatellites showed the opposite pattern. As expected under DAA, the observed genotypes combined more sequence diversity than expected under a random association of alleles. Thus, DAA may contribute to maintaining MHC polymorphism, which is ancient, as supported by signatures of historical positive selection and trans-species polymorphism. Our results point to the importance of a multi-scale approach in studying MHC variation, especially in low-dispersal taxa, which are genetically structured at fine spatial scales.
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Affiliation(s)
- Lorenzo Talarico
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, Rome, 00133, Italy.
| | - Wiesław Babik
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Kraków, 30-387, Poland
| | - Silvio Marta
- Department of Environmental Sciences and Policy, University of Milan, Via G. Celoria 26, Milan, 20133, Italy
| | - Venusta Pietrocini
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, Rome, 00133, Italy
| | - Marco Mattoccia
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, Rome, 00133, Italy
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21
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Pearson SK, Bull CM, Gardner MG. Selection outweighs drift at a fine scale: Lack of MHC differentiation within a family living lizard across geographically close but disconnected rocky outcrops. Mol Ecol 2018; 27:2204-2214. [PMID: 29603473 DOI: 10.1111/mec.14571] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 02/26/2018] [Accepted: 03/01/2018] [Indexed: 11/30/2022]
Abstract
The highly polymorphic genes of the major histocompatibility complex (MHC) are involved in disease resistance, mate choice and kin recognition. Therefore, they are widely used markers for investigating adaptive variation. Although selection is the key driver, gene flow and genetic drift also influence adaptive genetic variation, sometimes in opposing ways and with consequences for adaptive potential. To further understand the processes that generate MHC variation, it is helpful to compare variation at the MHC with that at neutral genetic loci. Differences in MHC and neutral genetic variation are useful for inferring the relative influence of selection, gene flow and drift on MHC variation. To date, such investigations have usually been undertaken at a broad spatial scale. Yet, evolutionary and ecological processes can occur at a fine spatial scale, particularly in small or fragmented populations. We investigated spatial patterns of MHC variation among three geographically close, naturally discrete, sampling sites of Egernia stokesii, an Australian lizard. The MHC of E. stokesii has recently been characterized, and there is evidence for historical selection on the MHC. We found E. stokesii MHC weakly differentiated among sites compared to microsatellites, suggesting selection, acting similarly at each site, has outweighed any effects of low gene flow or of genetic drift on E. stokesii MHC variation. Our findings demonstrate the strength of selection in shaping patterns of MHC variation or consistency at a fine spatial scale.
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Affiliation(s)
- Sarah K Pearson
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - C Michael Bull
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Michael G Gardner
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia.,Evolutionary Biology Unit, South Australian Museum, Adelaide, SA, Australia
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22
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Donaldson ME, Rico Y, Hueffer K, Rando HM, Kukekova AV, Kyle CJ. Development of a genotype-by-sequencing immunogenetic assay as exemplified by screening for variation in red fox with and without endemic rabies exposure. Ecol Evol 2017; 8:572-583. [PMID: 29321894 PMCID: PMC5756825 DOI: 10.1002/ece3.3583] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/28/2017] [Accepted: 10/02/2017] [Indexed: 12/30/2022] Open
Abstract
Pathogens are recognized as major drivers of local adaptation in wildlife systems. By determining which gene variants are favored in local interactions among populations with and without disease, spatially explicit adaptive responses to pathogens can be elucidated. Much of our current understanding of host responses to disease comes from a small number of genes associated with an immune response. High‐throughput sequencing (HTS) technologies, such as genotype‐by‐sequencing (GBS), facilitate expanded explorations of genomic variation among populations. Hybridization‐based GBS techniques can be leveraged in systems not well characterized for specific variants associated with disease outcome to “capture” specific genes and regulatory regions known to influence expression and disease outcome. We developed a multiplexed, sequence capture assay for red foxes to simultaneously assess ~300‐kbp of genomic sequence from 116 adaptive, intrinsic, and innate immunity genes of predicted adaptive significance and their putative upstream regulatory regions along with 23 neutral microsatellite regions to control for demographic effects. The assay was applied to 45 fox DNA samples from Alaska, where three arctic rabies strains are geographically restricted and endemic to coastal tundra regions, yet absent from the boreal interior. The assay provided 61.5% on‐target enrichment with relatively even sequence coverage across all targeted loci and samples (mean = 50×), which allowed us to elucidate genetic variation across introns, exons, and potential regulatory regions (4,819 SNPs). Challenges remained in accurately describing microsatellite variation using this technique; however, longer‐read HTS technologies should overcome these issues. We used these data to conduct preliminary analyses and detected genetic structure in a subset of red fox immune‐related genes between regions with and without endemic arctic rabies. This assay provides a template to assess immunogenetic variation in wildlife disease systems.
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Affiliation(s)
- Michael E Donaldson
- Environmental and Life Sciences Graduate Program Trent University Peterborough ON Canada
| | - Yessica Rico
- CONACYT Instituto de Ecología A.C.Centro Regional del Bajio Pátzcuaro Michoacán Mexico
| | - Karsten Hueffer
- Department of Veterinary Medicine University of Alaska Fairbanks Fairbanks AK USA
| | - Halie M Rando
- Department of Animal Sciences College of ACES University of Illinois at Urbana-Champaign Urbana IL USA
| | - Anna V Kukekova
- Department of Animal Sciences College of ACES University of Illinois at Urbana-Champaign Urbana IL USA
| | - Christopher J Kyle
- Environmental and Life Sciences Graduate Program Trent University Peterborough ON Canada.,Forensic Science Department Trent University Peterborough ON Canada
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23
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Donaldson ME, Davy CM, Willis CKR, McBurney S, Park A, Kyle CJ. Profiling the immunome of little brown myotis provides a yardstick for measuring the genetic response to white-nose syndrome. Evol Appl 2017; 10:1076-1090. [PMID: 29151862 PMCID: PMC5680615 DOI: 10.1111/eva.12514] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 06/26/2017] [Indexed: 12/19/2022] Open
Abstract
White‐nose syndrome (WNS) has devastated populations of hibernating bats in eastern North America, leading to emergency conservation listings for several species including the previously ubiquitous little brown myotis (Myotis lucifugus). However, some bat populations near the epicenter of the WNS panzootic appear to be stabilizing after initial precipitous declines, which could reflect a selective immunogenetic sweep. To investigate the hypothesis that WNS exerts significant selection on the immunome of affected bat populations, we developed a novel, high‐throughput sequence capture assay targeting 138 adaptive, intrinsic, and innate immunity genes of putative adaptive significance, as well as their respective regulatory regions (~370 kbp of genomic sequence/individual). We used the assay to explore baseline immunogenetic variation in M. lucifugus and to investigate whether particular immune genes/variants are associated with WNS susceptibility. We also used our assay to detect 1,038 putatively neutral single nucleotide polymorphisms and characterize contemporary population structure, providing context for the identification of local immunogenetic adaptation. Sequence capture provided a cost‐effective, “all‐in‐one” assay to test for neutral genetic and immunogenetic structure and revealed fine‐scale, baseline immunogenetic differentiation between sampling sites <600 km apart. We identified functional immunogenetic variants in M. lucifugus associated with WNS susceptibility. This study lays the foundations for future investigations of rangewide immunogenetic adaptation to WNS in M. lucifugus and provides a blueprint for studies of evolutionary rescue in other host–pathogen systems.
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Affiliation(s)
- Michael E Donaldson
- Environmental and Life Sciences Graduate Program Trent University Peterborough ON Canada
| | - Christina M Davy
- Environmental and Life Sciences Graduate Program Trent University Peterborough ON Canada.,Wildlife Research and Monitoring Section Ontario Ministry of Natural Resources and Forestry Peterborough ON Canada
| | - Craig K R Willis
- Department of Biology and Centre for Forest Interdisciplinary Research (C-FIR) University of Winnipeg Winnipeg MB Canada
| | - Scott McBurney
- Canadian Wildlife Health Cooperative Atlantic Region Atlantic Veterinary College University of Prince Edward Island Charlottetown PEI Canada
| | - Allysia Park
- Canadian Wildlife Health Cooperative Atlantic Region Atlantic Veterinary College University of Prince Edward Island Charlottetown PEI Canada
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24
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Cortázar-Chinarro M, Lattenkamp EZ, Meyer-Lucht Y, Luquet E, Laurila A, Höglund J. Drift, selection, or migration? Processes affecting genetic differentiation and variation along a latitudinal gradient in an amphibian. BMC Evol Biol 2017; 17:189. [PMID: 28806900 PMCID: PMC5557520 DOI: 10.1186/s12862-017-1022-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 07/26/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Past events like fluctuations in population size and post-glacial colonization processes may influence the relative importance of genetic drift, migration and selection when determining the present day patterns of genetic variation. We disentangle how drift, selection and migration shape neutral and adaptive genetic variation in 12 moor frog populations along a 1700 km latitudinal gradient. We studied genetic differentiation and variation at a MHC exon II locus and a set of 18 microsatellites. RESULTS Using outlier analyses, we identified the MHC II exon 2 (corresponding to the β-2 domain) locus and one microsatellite locus (RCO8640) to be subject to diversifying selection, while five microsatellite loci showed signals of stabilizing selection among populations. STRUCTURE and DAPC analyses on the neutral microsatellites assigned populations to a northern and a southern cluster, reflecting two different post-glacial colonization routes found in previous studies. Genetic variation overall was lower in the northern cluster. The signature of selection on MHC exon II was weaker in the northern cluster, possibly as a consequence of smaller and more fragmented populations. CONCLUSION Our results show that historical demographic processes combined with selection and drift have led to a complex pattern of differentiation along the gradient where some loci are more divergent among populations than predicted from drift expectations due to diversifying selection, while other loci are more uniform among populations due to stabilizing selection. Importantly, both overall and MHC genetic variation are lower at northern latitudes. Due to lower evolutionary potential, the low genetic variation in northern populations may increase the risk of extinction when confronted with emerging pathogens and climate change.
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Affiliation(s)
- Maria Cortázar-Chinarro
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden.
| | - Ella Z Lattenkamp
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
- Present address: Department of Neurogenetics of Vocal Communication, Max Planck Institute of Psycholinguistics, Box 310, 6500, Nijmegen, Netherlands
| | - Yvonne Meyer-Lucht
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
| | - Emilien Luquet
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
- Present address: Université Claude Bernard - Lyon I, CNRS, UMR 5023 - LEHNA, 3-6, rue Raphaël Dubois - Bâtiments Darwin C and Forel, 69622 Villeurbanne Cedex 43, Boulevard du 11 novembre, 1918, Lyon, France
| | - Anssi Laurila
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
| | - Jacob Höglund
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
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25
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Abduriyim S, Nishita Y, Kosintsev PA, Raichev E, Väinölä R, Kryukov AP, Abramov AV, Kaneko Y, Masuda R. Diversity and evolution of MHC class II DRB gene in the Eurasian badger genus Meles (Mammalia: Mustelidae). Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blx077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Small-scale intraspecific patterns of adaptive immunogenetic polymorphisms and neutral variation in Lake Superior lake trout. Immunogenetics 2017; 70:53-66. [PMID: 28547520 DOI: 10.1007/s00251-017-0996-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 04/26/2017] [Indexed: 10/19/2022]
Abstract
Many fishes express high levels of intraspecific variability, often linked to resource partitioning. Several studies show that a species' evolutionary trajectory of adaptive divergence can undergo reversals caused by changes in its environment. Such a reversal in neutral genetic and morphological variation among lake trout Salvelinus namaycush ecomorphs appears to be underway in Lake Superior. However, a water depth gradient in neutral genetic divergence was found to be associated with intraspecific diversity in the lake. To investigate patterns of adaptive immunogenetic variation among lake trout ecomorphs, we used Illumina high-throughput sequencing. The population's genetic structure of the major histocompatibility complex (MHC Class IIβ exon 2) and 18 microsatellite loci were compared to disentangle neutral and selective processes at a small geographic scale. Both MHC and microsatellite variation were partitioned more by water depth stratum than by ecomorph. Several metrics showed strong clustering by water depth in MHC alleles, but not microsatellites. We report a 75% increase in the number of MHC alleles shared between the predominant shallow and deep water ecomorphs since a previous lake trout MHC study at the same locale (c. 1990s data). This result is consistent with the reverse speciation hypothesis, although adaptive MHC polymorphisms persist along an ecological gradient. Finally, results suggested that the lake trout have multiple copies of the MHC II locus consistent with a historic genomic duplication event. Our findings indicated that conservation approaches for this species could focus on managing various ecological habitats by depth, in addition to regulating the fisheries specific to ecomorphs.
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27
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Santonastaso T, Lighten J, van Oosterhout C, Jones KL, Foufopoulos J, Anthony NM. The effects of historical fragmentation on major histocompatibility complex class II β and microsatellite variation in the Aegean island reptile, Podarcis erhardii. Ecol Evol 2017; 7:4568-4581. [PMID: 28690787 PMCID: PMC5496512 DOI: 10.1002/ece3.3022] [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: 08/15/2016] [Revised: 03/16/2017] [Accepted: 03/27/2017] [Indexed: 01/29/2023] Open
Abstract
The major histocompatibility complex (MHC) plays a key role in disease resistance and is the most polymorphic gene region in vertebrates. Although habitat fragmentation is predicted to lead to a loss in MHC variation through drift, the impact of other evolutionary forces may counter this effect. Here we assess the impact of selection, drift, migration, and recombination on MHC class II and microsatellite variability in 14 island populations of the Aegean wall lizard Podarcis erhardii. Lizards were sampled from islands within the Cyclades (Greece) formed by rising sea levels as the last glacial maximum approximately 20,000 before present. Bathymetric data were used to determine the area and age of each island, allowing us to infer the corresponding magnitude and timing of genetic bottlenecks associated with island formation. Both MHC and microsatellite variation were positively associated with island area, supporting the hypothesis that drift governs neutral and adaptive variation in this system. However, MHC but not microsatellite variability declined significantly with island age. This discrepancy is likely due to the fact that microsatellites attain mutation‐drift equilibrium more rapidly than MHC. Although we detected signals of balancing selection, recombination and migration, the effects of these evolutionary processes appeared negligible relative to drift. This study demonstrates how land bridge islands can provide novel insights into the impact of historical fragmentation on genetic diversity as well as help disentangle the effects of different evolutionary forces on neutral and adaptive diversity.
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Affiliation(s)
- Trent Santonastaso
- Department of Biological Sciences University of New Orleans New Orleans LA USA
| | - Jackie Lighten
- School of Environmental Sciences University of East Anglia Norwich Research Park Norwich UK
| | - Cock van Oosterhout
- School of Environmental Sciences University of East Anglia Norwich Research Park Norwich UK
| | - Kenneth L Jones
- Department of Biochemistry and Molecular Genetics University of Colorado Denver School of Medicine Denver CO USA
| | - Johannes Foufopoulos
- School of the Environment and Sustainability University of Michigan Ann Arbor MI USA
| | - Nicola M Anthony
- Department of Biological Sciences University of New Orleans New Orleans LA USA
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28
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Historical gene flow and profound spatial genetic structure among golden pheasant populations suggested by multi-locus analysis. Mol Phylogenet Evol 2017; 110:93-103. [PMID: 28286102 DOI: 10.1016/j.ympev.2017.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 12/06/2016] [Accepted: 03/06/2017] [Indexed: 12/23/2022]
Abstract
Major histocompatibility complex (MHC) is a good marker system for geographical genetics since they are functional genes in the immune system that are likely to affect the fitness of the individual, and the survival and evolutionary potential of a population in a changing environment. Golden pheasant (Chrysolophus pictus) is a wild Phasianidae distributed in central and north China. In this study, we used a locus-specific genotyping technique for MHC IIB genes of golden pheasant. Combining with microsatellites (simple sequence repeat, SSR) and mitochondrial DNA (mtDNA) D-loop region, we investigated the demographic history and illuminate genetic structure of this bird in detail. SYR (south of Yangtze river) - NYR (north of Yangtze river) lineages, separated by Yangtze River, were defined in genetic structure of MHC IIB. NYR was supposed as refuge during glacial period, suggested by diversity parameters and more ancient alleles in this region. Based on this hypothesis, there was gene flow from NYR to SYR, which was proved by three pieces of evidence: (1) distinct demographic histories of SYR (kept stable) and NYR (experienced expansion); (2) specific affiliation of LC in genetic structure of SSR and MHC genes; (3) significant gene flow from NYR to SYR. Moreover, we also found balancing selection by combination of three Grouping A2's regions (SC, QL and North) into one in Grouping B4 (NYR) and no pattern of isolation by distance (IBD) found in MHC IIB, whereas for SSR we found a relatively strong and significant IBD. Several mechanisms in the evolution of MHC IIB genes, including recombination, historically positive selection, trans-species evolution and concerted evolution, were shown by molecular and phylogenetic analysis. Overall these results suggest the Yangtze River was inferred to be a geological barrier for this avian and NYR might experience population expansion, which invaded into a neighboring region. This study contributes to the understanding of the effects of geographic features on contemporary patterns of genetic variation in the golden pheasant in China, and helps us to define the adaptive unite (AU) for this avian.
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29
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Rico Y, Ethier DM, Davy CM, Sayers J, Weir RD, Swanson BJ, Nocera JJ, Kyle CJ. Spatial patterns of immunogenetic and neutral variation underscore the conservation value of small, isolated American badger populations. Evol Appl 2016; 9:1271-1284. [PMID: 27877205 PMCID: PMC5108218 DOI: 10.1111/eva.12410] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 07/14/2016] [Indexed: 12/29/2022] Open
Abstract
Small and isolated populations often exhibit low genetic diversity due to drift and inbreeding, but may simultaneously harbour adaptive variation. We investigate spatial distributions of immunogenetic variation in American badger subspecies (Taxidea taxus), as a proxy for evaluating their evolutionary potential across the northern extent of the species' range. We compared genetic structure of 20 microsatellites and the major histocompatibility complex (MHC DRB exon 2) to evaluate whether small, isolated populations show low adaptive polymorphism relative to large and well-connected populations. Our results suggest that gene flow plays a prominent role in shaping MHC polymorphism across large spatial scales, while the interplay between gene flow and selection was stronger towards the northern peripheries. The similarity of MHC alleles within subspecies relative to their neutral genetic differentiation suggests that adaptive divergence among subspecies can be maintained despite ongoing gene flow along subspecies boundaries. Neutral genetic diversity was low in small relative to large populations, but MHC diversity within individuals was high in small populations. Despite reduced neutral genetic variation, small and isolated populations harbour functional variation that likely contribute to the species evolutionary potential at the northern range. Our findings suggest that conservation approaches should focus on managing adaptive variation across the species range rather than protecting subspecies per se.
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Affiliation(s)
- Yessica Rico
- Forensic Science DepartmentTrent UniversityPeterboroughONCanada
- Natural Resources DNA Profiling and Forensics CentreTrent UniversityPeterboroughONCanada
- Present address: CONACYTInstituto de Ecología A.C.Centro Regional del BajíoAvenida Lázaro Cárdenas 253PátzcuaroMichoacán61600México
| | - Danielle M. Ethier
- Ontario Badger ProjectGuelphONCanada
- Department of Integrative BiologyUniversity of GuelphGuelphONCanada
| | - Christina M. Davy
- Forensic Science DepartmentTrent UniversityPeterboroughONCanada
- Natural Resources DNA Profiling and Forensics CentreTrent UniversityPeterboroughONCanada
| | | | - Richard D. Weir
- Ecosystems Protection & Sustainability BranchMinistry of EnvironmentVictoriaBCCanada
| | | | - Joseph J. Nocera
- Wildlife Research and Monitoring SectionMinistry of Natural Resources & ForestryPeterboroughONCanada
| | - Christopher J. Kyle
- Forensic Science DepartmentTrent UniversityPeterboroughONCanada
- Natural Resources DNA Profiling and Forensics CentreTrent UniversityPeterboroughONCanada
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