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Dong PP, Wang RR, Abduriyim S. Diversity and evolution of the MHC class II DRB gene in the Capra sibirica experienced a demographic fluctuation in China. Sci Rep 2023; 13:19352. [PMID: 37935954 PMCID: PMC10630338 DOI: 10.1038/s41598-023-46717-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/03/2023] [Indexed: 11/09/2023] Open
Abstract
The major histocompatibility complex (MHC) genes are the most polymorphic genes in vertebrates, and their proteins play a critical role in adaptive immunity for defense against a variety of pathogens. MHC diversity was lost in many species after experiencing a decline in size. To understand the variation and evolution of MHC genes in the Siberian ibex, Capra sibirica, which has undergone a population decline, we analyzed the variation of the second exon of MHC class II DRB genes in samples collected from five geographic localities in Xinjiang, China, that belong to three diverged mitochondrial clades. Consequently, we identified a total of 26 putative functional alleles (PFAs) with 260 bp in length from 43 individuals, and found one (for 27 individuals) to three (for 5 individuals) PFAs per individual, indicating the presence of one or two DRB loci per haploid genome. The Casi-DRB1*16 was the most frequently occurring PFA, Casi-DRB1*22 was found in only seven individuals, 14 PFAs occurred once, 7 PFAs twice, implying high frequency of rare PFAs. Interestingly, more than half (15) of the PFAs were specific to clade I, only two and three PFAs were specific to clades II and III, respectively. So, we assume that the polygamy and sexual segregation nature of this species likely contributed to the allelic diversity of DRB genes. Genetic diversity indices showed that PFAs of clade II were lower in nucleotide, amino acid, and supertype diversity compared to those of the other two clades. The pattern of allele sharing and FST values between the three clades was to some extent in agreement with the pattern observed in mitochondrial DNA divergence. In addition, recombination analyses revealed no evidence for significant signatures of recombination events. Alleles shared by clades III and the other two clades diverged 6 million years ago, and systematic neighbor grids showed Trans-species polymorphism. Together with the PAML and MEME analyses, the results indicated that the DRB gene in C. sibirica evolved under balancing and positive selection. However, by comparison, it can be clearly seen that different populations were under different selective pressures. Our results are valuable in understanding the diversity and evolution of the DRB gene in a mountain living C. sibirica and in making decisions on future long-term protection strategies.
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Affiliation(s)
- Pei-Pei Dong
- College of Life Science, Shihezi University, Shihezi, 832003, Xinjiang, China
| | - Rui-Rui Wang
- College of Life Science, Shihezi University, Shihezi, 832003, Xinjiang, China
| | - Shamshidin Abduriyim
- College of Life Science, Shihezi University, Shihezi, 832003, Xinjiang, China.
- Xinjiang Production and Construction Corps Key Laboratory of Oasis Town and Mountain-Basin System Ecology, Shihezi University, Shihezi, 832003, Xinjiang, China.
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Napolitano C, Sacristán I, Acuña F, Aguilar E, García S, López-Jara MJ, Cabello J, Hidalgo-Hermoso E, Poulin E, Grueber CE. Assessing micro-macroparasite selective pressures and anthropogenic disturbance as drivers of immune gene diversity in a Neotropical wild cat. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 897:166289. [PMID: 37591403 DOI: 10.1016/j.scitotenv.2023.166289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 08/11/2023] [Accepted: 08/12/2023] [Indexed: 08/19/2023]
Abstract
Anthropogenic environmental change is reducing available habitat for wild species, providing novel selection pressures such as infectious diseases and causing species to interact in new ways. The potential for emerging infectious diseases and zoonoses at the interface between humans, domestic animals, and wild species is a key global concern. In vertebrates, diversity at the major histocompatibility complex MHC is critical to disease resilience, and its study in wild populations provides insights into eco-evolutionary dynamics that human activities alter. In natural populations, variation at MHC loci is partly maintained by balancing selection, driven by pathogenic selective pressures. We hypothesize that MHC genetic diversity differs between guigna populations inhabiting human-dominated landscapes (higher pathogen pressures) versus more natural habitats (lower pathogen pressures). We predict that MHC diversity in guignas would be highest in human-dominated landscapes compared with continuous forest habitats. We also expected to find higher MHC diversity in guignas infected with micro and macro parasites (higher parasite load) versus non infected guignas. We characterized for the first time the genetic diversity at three MHC class I and II exons in 128 wild guignas (Leopardus guigna) across their distribution range in Chile (32-46° S) and Argentina, representing landscapes with varying levels of human disturbance. We integrated MHC sequence diversity with multiple measures of anthropogenic disturbance and both micro and macro parasite infection data. We also assessed signatures of positive selection acting on MHC genes. We found significantly higher MHC class I diversity in guignas inhabiting landscapes where houses were present, and with lower percentage of vegetation cover, and also in animals with more severe cardiorespiratory helminth infection (richness and intensity) and micro-macroparasite co-infection. This comprehensive, landscape-level assessment further enhances our knowledge on the evolutionary dynamics and adaptive potential of vertebrates in the face of emerging infectious disease threats and increasing anthropogenic impacts.
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Affiliation(s)
- Constanza Napolitano
- Departamento de Ciencias Biológicas y Biodiversidad, Universidad de Los Lagos, Osorno, Chile; Institute of Ecology and Biodiversity (IEB), Concepción, Chile; Cape Horn International Center (CHIC), Puerto Williams, Chile.
| | - Irene Sacristán
- Universidad Andres Bello, Santiago, Chile; Animal Health Research Centre, National Institute for Agricultural and Food Research and Technology (INIA), Centro Superior de Investigaciones Científicas (CSIC), Valdeolmos, Madrid, Spain
| | - Francisca Acuña
- Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Emilio Aguilar
- Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Sebastián García
- Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - María José López-Jara
- Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Javier Cabello
- Chiloé Silvestre Center for the Conservation of Biodiversity, Ancud, Chile
| | | | - Elie Poulin
- Institute of Ecology and Biodiversity (IEB), Concepción, Chile; Millennium Institute of Biodiversity of Antarctic and Subantarctic Ecosystems and Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Catherine E Grueber
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, Australia
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Awadi A, Suchentrunk F, Knauer F, Smith S, Tolesa Z, Ben Slimen H. Spatial diversity of MHC class II DRB exon2 sequences in North African cape hares (Lepus capensis): positive selection and climatic adaptation signals. Mamm Biol 2022. [DOI: 10.1007/s42991-022-00258-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Buzan E, Potušek S, Duniš L, Pokorny B. Neutral and Selective Processes Shape MHC Diversity in Roe Deer in Slovenia. Animals (Basel) 2022; 12:ani12060723. [PMID: 35327121 PMCID: PMC8944837 DOI: 10.3390/ani12060723] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 02/23/2022] [Accepted: 03/10/2022] [Indexed: 12/21/2022] Open
Abstract
Simple Summary Disease prevention and appropriate wildlife management are among the major challenges in wildlife conservation. In the present study, we made a first assessment of the variability of major histocompatibility complex (MHC) genes in roe deer in Slovenia and evaluated local population adaptation by comparing MHC variability with neutral microsatellites. We discovered three new MHC DRB exon 2 alleles in addition to seven previously described in the literature. Moreover, we found evidence of historical positive selection, as selection analysis indicated that approx. 10% of the encoded amino acids were subjected to episodic positive selection. This study provides the basis for further research on immunogenetic variation in roe deer and highlights opportunities to incorporate genetic data into science-based population management. Abstract Disease control and containment in free-ranging populations is one of the greatest challenges in wildlife management. Despite the importance of major histocompatibility complex (MHC) genes for immune response, an assessment of the diversity and occurrence of these genes is still rare in European roe deer, the most abundant and widespread large mammal in Europe. Therefore, we examined immunogenetic variation in roe deer in Slovenia to identify species adaptation by comparing the genetic diversity of the MHC genes with the data on neutral microsatellites. We found ten MHC DRB alleles, three of which are novel. Evidence for historical positive selection on the MHC was found using the maximum likelihood codon method. Patterns of MHC allelic distribution were not congruent with neutral population genetic findings. The lack of population genetic differentiation in MHC genes compared to existing structure in neutral markers suggests that MHC polymorphism was influenced primarily by balancing selection and, to a lesser extent, by neutral processes such as genetic drift, with no clear evidence of local adaptation. Selection analyses indicated that approx. 10% of amino acids encoded under episodic positive selection. This study represents one of the first steps towards establishing an immunogenetic map of roe deer populations across Europe, aiming to better support science-based management of this important game species.
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Affiliation(s)
- Elena Buzan
- Faculty of Mathematics, Natural Sciences, and Information Technologies, University of Primorska, Glagoljaška 8, 6000 Koper, Slovenia; (S.P.); (L.D.)
- Environmental Protection College, Trg Mladosti 7, 3320 Velenje, Slovenia;
- Correspondence: ; Tel.: +38-65-6117570; Fax: +38-65-61175
| | - Sandra Potušek
- Faculty of Mathematics, Natural Sciences, and Information Technologies, University of Primorska, Glagoljaška 8, 6000 Koper, Slovenia; (S.P.); (L.D.)
| | - Luka Duniš
- Faculty of Mathematics, Natural Sciences, and Information Technologies, University of Primorska, Glagoljaška 8, 6000 Koper, Slovenia; (S.P.); (L.D.)
| | - Boštjan Pokorny
- Environmental Protection College, Trg Mladosti 7, 3320 Velenje, Slovenia;
- Slovenian Forestry Institute, Večna pot 2, 1000 Ljubljana, Slovenia
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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: 0.5] [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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6
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Quéméré E, Rossi S, Petit E, Marchand P, Merlet J, Game Y, Galan M, Gilot-Fromont E. Genetic epidemiology of the Alpine ibex reservoir of persistent and virulent brucellosis outbreak. Sci Rep 2020; 10:4400. [PMID: 32157133 PMCID: PMC7064506 DOI: 10.1038/s41598-020-61299-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 02/25/2020] [Indexed: 01/23/2023] Open
Abstract
While it is now broadly accepted that inter-individual variation in the outcomes of host-pathogen interactions is at least partially genetically controlled, host immunogenetic characteristics are rarely investigated in wildlife epidemiological studies. Furthermore, most immunogenetic studies in the wild focused solely on the major histocompatibility complex (MHC) diversity despite it accounts for only a fraction of the genetic variation in pathogen resistance. Here, we investigated immunogenetic diversity of the Alpine ibex (Capra ibex) population of the Bargy massif, reservoir of a virulent outbreak of brucellosis. We analysed the polymorphism and associations with disease resistance of the MHC Class II Drb gene and several non-MHC genes (Toll-like receptor genes, Slc11A1) involved in the innate immune response to Brucella in domestic ungulates. We found a very low neutral genetic diversity and a unique MHC Drb haplotype in this population founded few decades ago from a small number of individuals. By contrast, other immunity-related genes have maintained polymorphism and some showed significant associations with the brucellosis infection status hence suggesting a predominant role of pathogen-mediated selection in their recent evolutionary trajectory. Our results highlight the need to monitor immunogenetic variation in wildlife epidemiological studies and to look beyond the MHC.
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Affiliation(s)
- Erwan Quéméré
- CEFS, INRAE, Université de Toulouse, Castanet-Tolosan, France.
- ESE, Ecology and Ecosystems Health, Agrocampus Ouest, INRAE, 35042 Rennes, France.
| | - Sophie Rossi
- Office Français de la Biodiversité, Unité Sanitaire de la Faune, Gap, France
| | - Elodie Petit
- Office Français de la Biodiversité, Unité Ongulés sauvages, Gières, France
| | - Pascal Marchand
- Office Français de la Biodiversité, Unité Ongulés sauvages, Gières, France
| | - Joël Merlet
- CEFS, INRAE, Université de Toulouse, Castanet-Tolosan, France
| | - Yvette Game
- Laboratoire Départemental d'Analyses Vétérinaires de Savoie, Chambéry, France
| | - Maxime Galan
- CBGP, INRAE, CIRAD, IRD, Montpellier SupAgro, Univ Montpellier, Montpellier, France
| | - Emmanuelle Gilot-Fromont
- Université de Lyon, VetAgro Sup - Campus vétérinaire de Lyon, Marcy l'Étoile, France
- Université de Lyon 1, UMR CNRS 5558 Laboratoire de Biométrie et Biologie Evolutive (LBBE), Villeurbanne, France
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7
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Sequence diversity of MHC class-II DRB gene in gazelles (Gazella subgutturosa) raised in Sanliurfa of Turkey. J Genet 2018. [DOI: 10.1007/s12041-018-0974-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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8
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Brambilla A, Keller L, Bassano B, Grossen C. Heterozygosity-fitness correlation at the major histocompatibility complex despite low variation in Alpine ibex ( Capra ibex). Evol Appl 2018; 11:631-644. [PMID: 29875807 PMCID: PMC5979623 DOI: 10.1111/eva.12575] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/30/2017] [Indexed: 01/06/2023] Open
Abstract
Crucial for the long-term survival of wild populations is their ability to fight diseases. Disease outbreaks can lead to severe population size reductions, which makes endangered and reintroduced species especially vulnerable. In vertebrates, the major histocompatibility complex (MHC) plays an important role in determining the immune response. Species that went through severe bottlenecks often show very low levels of genetic diversity at the MHC. Due to the known link between the MHC and immune response, such species are expected to be at particular risk in case of disease outbreaks. However, so far, only few studies have shown that low MHC diversity is correlated with increased disease susceptibility in species after severe bottlenecks. We investigated genetic variation at the MHC and its correlations with disease resistance and other fitness-related traits in Alpine ibex (Capra ibex), a wild goat species that underwent a strong bottleneck in the last century and that is known to have extremely low genetic variability, both genome-wide and at the MHC. We studied MHC variation in male ibex of Gran Paradiso National Park, the population used as a source for all postbottleneck reintroductions. We found that individual MHC heterozygosity (based on six microsatellites) was not correlated with genome-wide neutral heterozygosity. MHC heterozygosity, but not genome-wide heterozygosity, was positively correlated with resistance to infectious keratoconjunctivitis and with body mass. Our results show that genetic variation at the MHC plays an important role in disease resistance and, hence, should be taken into account for successfully managing species conservation.
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Affiliation(s)
- Alice Brambilla
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurich (ZH)Switzerland
- Alpine Wildlife Research CentreGran Paradiso National ParkNoasca (TO)Italy
| | - Lukas Keller
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurich (ZH)Switzerland
| | - Bruno Bassano
- Alpine Wildlife Research CentreGran Paradiso National ParkNoasca (TO)Italy
| | - Christine Grossen
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurich (ZH)Switzerland
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9
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Angelone S, Jowers MJ, Molinar Min AR, Fandos P, Prieto P, Pasquetti M, Cano-Manuel FJ, Mentaberre G, Olvera JRL, Ráez-Bravo A, Espinosa J, Pérez JM, Soriguer RC, Rossi L, Granados JE. Hidden MHC genetic diversity in the Iberian ibex (Capra pyrenaica). BMC Genet 2018; 19:28. [PMID: 29739323 PMCID: PMC5941765 DOI: 10.1186/s12863-018-0616-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 04/30/2018] [Indexed: 01/09/2023] Open
Abstract
Background Defining hidden genetic diversity within species is of great significance when attempting to maintain the evolutionary potential of natural populations and conduct appropriate management. Our hypothesis is that isolated (and eventually small) wild animal populations hide unexpected genetic diversity due to their maintenance of ancient polymorphisms or introgressions. Results We tested this hypothesis using the Iberian ibex (Capra pyrenaica) as an example. Previous studies based on large sample sizes taken from its principal populations have revealed that the Iberian ibex has a remarkably small MHC DRB1 diversity (only six remnant alleles) as a result of recent population bottlenecks and a marked demographic decline that has led to the extinction of two recognized subspecies. Extending on the geographic range to include non-studied isolated Iberian ibex populations, we sequenced a new MHC DRB1 in what seemed three small isolated populations in Southern Spain (n = 132). The findings indicate a higher genetic diversity than previously reported in this important gene. The newly discovered allele, MHC DRB1*7, is identical to one reported in the domestic goat C. aegagrus hircus. Whether or not this is the result of ancient polymorphisms maintained by balancing selection or, alternatively, introgressions from domestic goats through hybridization needs to be clarified in future studies. However, hybridization between Iberian ibex and domestic goats has been reported in Spain and the fact that the newly discovered allele is only present in one of the small isolated populations and not in the others suggests introgression. The new discovered allele is not expected to increase fitness in C. pyrenaica since it generates the same protein as the existing MHC DRB1*6. Analysis of a microsatellite locus (OLADRB1) near the new MHC DRB1*7 gene reveals a linkage disequilibrium between these two loci. The allele OLADRB1, 187 bp in length, was unambiguously linked to the MHC DRB1*7 allele. This enabled us to perform a DRB-STR matching method for the recently discovered MHC allele. Conclusions This finding is critical for the conservation of the Iberian ibex since it directly affects the identification of the units of this species that should be managed and conserved separately (Evolutionarily Significant Units). Electronic supplementary material The online version of this article (10.1186/s12863-018-0616-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Samer Angelone
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Américo Vespucio s/n, 41092, Sevilla, Spain. .,Institute of Evolutionary Biology and Environmental Studies (IEU), University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland.
| | - Michael J Jowers
- CIBIO/ InBIO (Centro de Investigação em Biodiversidade e Recursos Genéticos), Universidade do Porto, Campus Agrario De Vairão, 4485-661, Vairão, Portugal
| | - Anna Rita Molinar Min
- Dipartimento di Scienze Veterinarie, Universita` degli Studi di Torino, Grugliasco, Italy
| | - Paulino Fandos
- Agencia de Medio Ambiente y Agua, E-41092, Sevilla, Isla de la Cartuja, Spain
| | - Paloma Prieto
- Parque Natural Sierras de Cazorla, Segura y Las Villas, Martínez Falero11, E-23470, Cazorla, Jaén, Spain
| | - Mario Pasquetti
- Dipartimento di Scienze Veterinarie, Universita` degli Studi di Torino, Grugliasco, Italy
| | | | - Gregorio Mentaberre
- Servei d'Ecopatologia de Fauna Salvatge (SEFAS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), E-08193 Bellaterra, Barcelona, Spain
| | - Jorge Ramón López Olvera
- Servei d'Ecopatologia de Fauna Salvatge (SEFAS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), E-08193 Bellaterra, Barcelona, Spain
| | - Arián Ráez-Bravo
- Servei d'Ecopatologia de Fauna Salvatge (SEFAS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), E-08193 Bellaterra, Barcelona, Spain
| | - José Espinosa
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus Las Lagunillas, s.n., E-23071, Jaén, Spain
| | - Jesús M Pérez
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus Las Lagunillas, s.n., E-23071, Jaén, Spain
| | - Ramón C Soriguer
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Américo Vespucio s/n, 41092, Sevilla, Spain
| | - Luca Rossi
- Dipartimento di Scienze Veterinarie, Universita` degli Studi di Torino, Grugliasco, Italy
| | - José Enrique Granados
- Espacio Natural Sierra Nevada, Carretera Antigua de Sierra Nevada, Km 7, E-18071, Pinos Genil, Granada, Spain
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10
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Mulder KP, Cortazar-Chinarro M, Harris DJ, Crottini A, Campbell Grant EH, Fleischer RC, Savage AE. Evolutionary dynamics of an expressed MHC class IIβ locus in the Ranidae (Anura) uncovered by genome walking and high-throughput amplicon sequencing. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 76:177-188. [PMID: 28587861 DOI: 10.1016/j.dci.2017.05.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 05/30/2017] [Accepted: 05/30/2017] [Indexed: 06/07/2023]
Abstract
The Major Histocompatibility Complex (MHC) is a genomic region encoding immune loci that are important and frequently used markers in studies of adaptive genetic variation and disease resistance. Given the primary role of infectious diseases in contributing to global amphibian declines, we characterized the hypervariable exon 2 and flanking introns of the MHC Class IIβ chain for 17 species of frogs in the Ranidae, a speciose and cosmopolitan family facing widespread pathogen infections and declines. We find high levels of genetic variation concentrated in the Peptide Binding Region (PBR) of the exon. Ten codons are under positive selection, nine of which are located in the mammal-defined PBR. We hypothesize that the tenth codon (residue 21) is an amphibian-specific PBR site that may be important in disease resistance. Trans-species and trans-generic polymorphisms are evident from exon-based genealogies, and co-phylogenetic analyses between intron, exon and mitochondrial based reconstructions reveal incongruent topologies, likely due to different locus histories. We developed two sets of barcoded adapters that reliably amplify a single and likely functional locus in all screened species using both 454 and Illumina based sequencing methods. These primers provide a resource for multiplexing and directly sequencing hundreds of samples in a single sequencing run, avoiding the labour and chimeric sequences associated with cloning, and enabling MHC population genetic analyses. Although the primers are currently limited to the 17 species we tested, these sequences and protocols provide a useful genetic resource and can serve as a starting point for future disease, adaptation and conservation studies across a range of anuran taxa.
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Affiliation(s)
- Kevin P Mulder
- Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, 3001 Connecticut Avenue NW, Washington, DC 20008, USA; CIBIO/InBIO, Research Centre in Biodiversity and Genetic Resources, Rua Padre Armando Quintas 7, Campus Agrário de Vairão, 4485-661 Vairão, Portugal
| | - Maria Cortazar-Chinarro
- Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden
| | - D James Harris
- CIBIO/InBIO, Research Centre in Biodiversity and Genetic Resources, Rua Padre Armando Quintas 7, Campus Agrário de Vairão, 4485-661 Vairão, Portugal
| | - Angelica Crottini
- CIBIO/InBIO, Research Centre in Biodiversity and Genetic Resources, Rua Padre Armando Quintas 7, Campus Agrário de Vairão, 4485-661 Vairão, Portugal
| | - Evan H Campbell Grant
- United States Geological Survey, Patuxent Wildlife Research Center, SO Conte Anadromous Fish Research Lab, 1 Migratory Way, Turner Falls, MA 01376, USA
| | - Robert C Fleischer
- Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, 3001 Connecticut Avenue NW, Washington, DC 20008, USA
| | - Anna E Savage
- Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, 3001 Connecticut Avenue NW, Washington, DC 20008, USA; Department of Biology, University of Central Florida, 4110 Libra Drive, Orlando, FL 32816, USA.
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11
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Savage AE, Mulder KP, Torres T, Wells S. Lost but not forgotten: MHC genotypes predict overwinter survival despite depauperate MHC diversity in a declining frog. CONSERV GENET 2017. [DOI: 10.1007/s10592-017-1001-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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12
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Marmesat E, Schmidt K, Saveljev AP, Seryodkin IV, Godoy JA. Retention of functional variation despite extreme genomic erosion: MHC allelic repertoires in the Lynx genus. BMC Evol Biol 2017; 17:158. [PMID: 28676046 PMCID: PMC5496644 DOI: 10.1186/s12862-017-1006-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/23/2017] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Demographic bottlenecks erode genetic diversity and may increase endangered species' extinction risk via decreased fitness and adaptive potential. The genetic status of species is generally assessed using neutral markers, whose dynamic can differ from that of functional variation due to selection. The MHC is a multigene family described as the most important genetic component of the mammalian immune system, with broad implications in ecology and evolution. The genus Lynx includes four species differing immensely in demographic history and population size, which provides a suitable model to study the genetic consequences of demographic declines: the Iberian lynx being an extremely bottlenecked species and the three remaining ones representing common and widely distributed species. We compared variation in the most variable exon of the MHCI and MHCII-DRB loci among the four species of the Lynx genus. RESULTS The Iberian lynx was characterised by lower number of MHC alleles than its sister species (the Eurasian lynx). However, it maintained most of the functional genetic variation at MHC loci present in the remaining and genetically healthier lynx species at all nucleotide, amino acid, and supertype levels. CONCLUSIONS Species-wide functional genetic diversity can be maintained even in the face of severe population bottlenecks, which caused devastating whole genome genetic erosion. This could be the consequence of divergent alleles being retained across paralogous loci, an outcome that, in the face of frequent gene conversion, may have been favoured by balancing selection.
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Affiliation(s)
- Elena Marmesat
- Department of Integrative Ecology, Estación Biológica de Doñana (CSIC), C/Américo Vespucio, 26, 41092, Sevilla, Spain
| | - Krzysztof Schmidt
- Mammal Research Institute, Polish Academy of Sciences, 17-230, Białowieża, Poland
| | - Alexander P Saveljev
- Department of Animal Ecology, Russian Research Institute of Game Management and Fur Farming, 79 Preobrazhenskaya Str, Kirov, 610000, Russia
| | - Ivan V Seryodkin
- Laboratory of Ecology and Conservation of Animals, Pacific Institute of Geography of Far East Branch of Russian Academy of Sciences, 7 Radio Street, Vladivostok, 690041, Russia
- Far Eastern Federal University, 8 Sukhanova Street, Vladivostok, 690091, Russia
| | - José A Godoy
- Department of Integrative Ecology, Estación Biológica de Doñana (CSIC), C/Américo Vespucio, 26, 41092, Sevilla, Spain.
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13
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Heinrich SK, Hofer H, Courtiol A, Melzheimer J, Dehnhard M, Czirják GÁ, Wachter B. Cheetahs have a stronger constitutive innate immunity than leopards. Sci Rep 2017; 7:44837. [PMID: 28333126 PMCID: PMC5363065 DOI: 10.1038/srep44837] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 02/14/2017] [Indexed: 11/21/2022] Open
Abstract
As a textbook case for the importance of genetics in conservation, absence of genetic variability at the major histocompatibility complex (MHC) is thought to endanger species viability, since it is considered crucial for pathogen resistance. An alternative view of the immune system inspired by life history theory posits that a strong response should evolve in other components of the immune system if there is little variation in the MHC. In contrast to the leopard (Panthera pardus), the cheetah (Acinonyx jubatus) has a relatively low genetic variability at the MHC, yet free-ranging cheetahs are healthy. By comparing the functional competence of the humoral immune system of both species in sympatric populations in Namibia, we demonstrate that cheetahs have a higher constitutive innate but lower induced innate and adaptive immunity than leopards. We conclude (1) immunocompetence of cheetahs is higher than previously thought; (2) studying both innate and adaptive components of immune systems will enrich conservation science.
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Affiliation(s)
- Sonja K. Heinrich
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | - Heribert Hofer
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | - Alexandre Courtiol
- Department of Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | - Jörg Melzheimer
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | - Martin Dehnhard
- Department of Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | - Gábor Á. Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | - Bettina Wachter
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
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14
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Roffler GH, Amish SJ, Smith S, Cosart T, Kardos M, Schwartz MK, Luikart G. SNP discovery in candidate adaptive genes using exon capture in a free-ranging alpine ungulate. Mol Ecol Resour 2016; 16:1147-64. [PMID: 27327375 DOI: 10.1111/1755-0998.12560] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 06/04/2016] [Accepted: 06/07/2016] [Indexed: 11/30/2022]
Abstract
Identification of genes underlying genomic signatures of natural selection is key to understanding adaptation to local conditions. We used targeted resequencing to identify SNP markers in 5321 candidate adaptive genes associated with known immunological, metabolic and growth functions in ovids and other ungulates. We selectively targeted 8161 exons in protein-coding and nearby 5' and 3' untranslated regions of chosen candidate genes. Targeted sequences were taken from bighorn sheep (Ovis canadensis) exon capture data and directly from the domestic sheep genome (Ovis aries v. 3; oviAri3). The bighorn sheep sequences used in the Dall's sheep (Ovis dalli dalli) exon capture aligned to 2350 genes on the oviAri3 genome with an average of 2 exons each. We developed a microfluidic qPCR-based SNP chip to genotype 476 Dall's sheep from locations across their range and test for patterns of selection. Using multiple corroborating approaches (lositan and bayescan), we detected 28 SNP loci potentially under selection. We additionally identified candidate loci significantly associated with latitude, longitude, precipitation and temperature, suggesting local environmental adaptation. The three methods demonstrated consistent support for natural selection on nine genes with immune and disease-regulating functions (e.g. Ovar-DRA, APC, BATF2, MAGEB18), cell regulation signalling pathways (e.g. KRIT1, PI3K, ORRC3), and respiratory health (CYSLTR1). Characterizing adaptive allele distributions from novel genetic techniques will facilitate investigation of the influence of environmental variation on local adaptation of a northern alpine ungulate throughout its range. This research demonstrated the utility of exon capture for gene-targeted SNP discovery and subsequent SNP chip genotyping using low-quality samples in a nonmodel species.
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Affiliation(s)
- Gretchen H Roffler
- Alaska Science Center, U.S. Geological Survey, 4210 University Drive, Anchorage, AK, 99508, USA.,Wildlife Biology Program, Department of Ecosystem Sciences and Conservation, College of Forestry and Conservation, University of Montana, Missoula, MT, 59812, USA
| | - Stephen J Amish
- Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Seth Smith
- Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Ted Cosart
- Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Marty Kardos
- Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA.,Evolutionary Biology Centre, Uppsala University, SE-75236, Uppsala, Sweden
| | - Michael K Schwartz
- Evolutionary Biology Centre, Uppsala University, SE-75236, Uppsala, Sweden.,US Forest Service Rocky Mountain Research Station, National Genomics Center for Wildlife and Fish Conservation, 800 E. Beckwith Ave., Missoula, MT, 59801, USA
| | - Gordon Luikart
- Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA.,Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, USA
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15
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Biedrzycka A, Kloch A. Development of novel associations between MHC alleles and susceptibility to parasitic infections in an isolated population of an endangered mammal. INFECTION GENETICS AND EVOLUTION 2016; 44:210-217. [PMID: 27423515 DOI: 10.1016/j.meegid.2016.07.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/11/2016] [Accepted: 07/12/2016] [Indexed: 10/21/2022]
Abstract
The role of pathogens in dynamics of endangered species is not fully understood, and the effect of infection often interacts with other processes affecting those species, such as fragmentation and isolation or loss of genetic variation. Small, isolated populations are prone to losing functional alleles due to demographic processes and genetic drift, which may diminish their ability to resist infection if immune genes are affected. Demographic processes may also alter the selective pressure exerted by a parasite, as they influence the rate of parasite transmission between individuals. In the present paper we studied changes in parasite infection levels and genetic variability in an isolated population of spotted suslik (Spermophillus suslicus). Over a three-year period (approx. three generations), when the population size remained relatively stable, we observed a considerable increase in parasite prevalence and infection intensity, followed by the development of novel associations between MHC DRB alleles and parasite burden. Contrary to expectations, the change in MHC allele frequency over time was not consistent with the effect of the allele - for instance, Spsu-DRB*07, associated with higher intensity of infection with a nematode Capillaria sp., increased in frequency from 11.8 to 20.2%. Yet, we found no signatures of selection in the studied loci. Our results show that an isolated, stable population may experience a sudden increase in parasitic infections, resulting in a development of novel associations between MHC alleles and parasite susceptibility/resistance, even though no signatures of selection can be found.
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Affiliation(s)
- Aleksandra Biedrzycka
- Institute of Nature Conservation, Polish Academy of Sciences, al. A. Mickiewicza 33, 31-120 Kraków, Poland.
| | - Agnieszka Kloch
- Department of Ecology, Biological and Chemical Research Centre, Faculty of Biology, University of Warsaw, ul. Żwirki i Wigury 101, 02-089 Warszawa, Poland.
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16
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Jaeger CP, Duvall MR, Swanson BJ, Phillips CA, Dreslik MJ, Baker SJ, King RB. Microsatellite and major histocompatibility complex variation in an endangered rattlesnake, the Eastern Massasauga (Sistrurus catenatus). Ecol Evol 2016; 6:3991-4003. [PMID: 27516858 PMCID: PMC4874855 DOI: 10.1002/ece3.2159] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 01/18/2023] Open
Abstract
Genetic diversity is fundamental to maintaining the long-term viability of populations, yet reduced genetic variation is often associated with small, isolated populations. To examine the relationship between demography and genetic variation, variation at hypervariable loci (e.g., microsatellite DNA loci) is often measured. However, these loci are selectively neutral (or near neutral) and may not accurately reflect genomewide variation. Variation at functional trait loci, such as the major histocompatibility complex (MHC), can provide a better assessment of adaptive genetic variation in fragmented populations. We compared patterns of microsatellite and MHC variation across three Eastern Massasauga (Sistrurus catenatus) populations representing a gradient of demographic histories to assess the relative roles of natural selection and genetic drift. Using 454 deep amplicon sequencing, we identified 24 putatively functional MHC IIB exon 2 alleles belonging to a minimum of six loci. Analysis of synonymous and nonsynonymous substitution rates provided evidence of historical positive selection at the nucleotide level, and Tajima's D provided support for balancing selection in each population. As predicted, estimates of microsatellite allelic richness, observed, heterozygosity, and expected heterozygosity varied among populations in a pattern qualitatively consistent with demographic history and abundance. While MHC allelic richness at the population and individual levels revealed similar trends, MHC nucleotide diversity was unexpectedly high in the smallest population. Overall, these results suggest that genetic variation in the Eastern Massasauga populations in Illinois has been shaped by multiple evolutionary mechanisms. Thus, conservation efforts should consider both neutral and functional genetic variation when managing captive and wild Eastern Massasauga populations.
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Affiliation(s)
- Collin P. Jaeger
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
| | - Melvin R. Duvall
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
| | - Bradley J. Swanson
- Department of BiologyCentral Michigan UniversityMt. PleasantMichigan48859
| | - Christopher A. Phillips
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Michael J. Dreslik
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Sarah J. Baker
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Richard B. King
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
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17
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Buhler S, Nunes JM, Sanchez-Mazas A. HLA class I molecular variation and peptide-binding properties suggest a model of joint divergent asymmetric selection. Immunogenetics 2016; 68:401-416. [PMID: 27233953 PMCID: PMC4911380 DOI: 10.1007/s00251-016-0918-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/17/2016] [Indexed: 01/20/2023]
Abstract
The main function of HLA class I molecules is to present pathogen-derived peptides to cytotoxic T lymphocytes. This function is assumed to drive the maintenance of an extraordinary amount of polymorphism at each HLA locus, providing an immune advantage to heterozygote individuals capable to present larger repertories of peptides than homozygotes. This seems contradictory, however, with a reduced diversity at individual HLA loci exhibited by some isolated populations. This study shows that the level of functional diversity predicted for the two HLA-A and HLA-B genes considered simultaneously is similar (almost invariant) between 46 human populations, even when a reduced diversity exists at each locus. We thus propose that HLA-A and HLA-B evolved through a model of joint divergent asymmetric selection conferring all populations an equivalent immune potential. The distinct pattern observed for HLA-C is explained by its functional evolution towards killer cell immunoglobulin-like receptor (KIR) activity regulation rather than peptide presentation.
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Affiliation(s)
- Stéphane Buhler
- Laboratory of Anthropology, Genetics and Peopling History, Department of Genetics and Evolution, Anthropology Unit, University of Geneva, Geneva, Switzerland. .,Transplantation Immunology Unit & National Reference Laboratory for Histocompatibility, Department of Genetic and Laboratory Medicine, Geneva University Hospital, Geneva, Switzerland.
| | - José Manuel Nunes
- Laboratory of Anthropology, Genetics and Peopling History, Department of Genetics and Evolution, Anthropology Unit, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Alicia Sanchez-Mazas
- Laboratory of Anthropology, Genetics and Peopling History, Department of Genetics and Evolution, Anthropology Unit, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
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18
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Ballingall KT, McIntyre A, Lin Z, Timmerman N, Matthysen E, Lurz PW, Melville L, Wallace A, Meredith AL, Romeo C, Wauters LA, Sainsbury AW, McInnes CJ. Limited diversity associated with duplicated class II MHC-DRB genes in the red squirrel population in the United Kingdom compared with continental Europe. CONSERV GENET 2016. [DOI: 10.1007/s10592-016-0852-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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19
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Cai R, Shafer ABA, Laguardia A, Lin Z, Liu S, Hu D. Recombination and selection in the major histocompatibility complex of the endangered forest musk deer (Moschus berezovskii). Sci Rep 2015; 5:17285. [PMID: 26603338 PMCID: PMC4658564 DOI: 10.1038/srep17285] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 10/28/2015] [Indexed: 11/18/2022] Open
Abstract
The forest musk deer (Moschus berezovskii) is a high elevation species distributed across western China and northern Vietnam. Once abundant, habitat loss and poaching has led to a dramatic decrease in population numbers prompting the IUCN to list the species as endangered. Here, we characterized the genetic diversity of a Major Histocompatibility Complex (MHC) locus and teased apart driving factors shaping its variation. Seven DRB exon 2 alleles were identified among a group of randomly sampled forest musk deer from a captive population in the Sichuan province of China. Compared to other endangered or captive ungulates, forest musk deer have relatively low levels of MHC genetic diversity. Non-synonymous substitutions primarily occurred in the putative peptide-binding region (PBR), with analyses suggesting that recombination and selection has shaped the genetic diversity across the locus. Specifically, inter-allelic recombination generated novel allelic combinations, with evidence for both positive selection acting on the PBR and negative selection on the non-PBR. An improved understanding of functional genetic variability of the MHC will facilitate better design and management of captive breeding programs for this endangered species.
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Affiliation(s)
- Ruibo Cai
- College of Nature Conservation, Beijing Forestry University, China
| | | | - Alice Laguardia
- College of Nature Conservation, Beijing Forestry University, China
| | - Zhenzhen Lin
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Shuqiang Liu
- College of Nature Conservation, Beijing Forestry University, China
| | - Defu Hu
- College of Nature Conservation, Beijing Forestry University, China
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20
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Li B, Xu Y, Ma J. Allelic characterization of the second DRB locus of major histocompatibility complex class II in Ussuri sika deer (Cervus nippon hortulorum): highlighting the trans-species evolution of DRB alleles within Cervidae. Anim Cells Syst (Seoul) 2013. [DOI: 10.1080/19768354.2013.826280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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21
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Osborne AJ, Zavodna M, Chilvers BL, Robertson BC, Negro SS, Kennedy MA, Gemmell NJ. Extensive variation at MHC DRB in the New Zealand sea lion (Phocarctos hookeri) provides evidence for balancing selection. Heredity (Edinb) 2013; 111:44-56. [PMID: 23572124 PMCID: PMC3692317 DOI: 10.1038/hdy.2013.18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Revised: 12/20/2012] [Accepted: 01/28/2013] [Indexed: 11/09/2022] Open
Abstract
Marine mammals are often reported to possess reduced variation of major histocompatibility complex (MHC) genes compared with their terrestrial counterparts. We evaluated diversity at two MHC class II B genes, DQB and DRB, in the New Zealand sea lion (Phocarctos hookeri, NZSL) a species that has suffered high mortality owing to bacterial epizootics, using Sanger sequencing and haplotype reconstruction, together with next-generation sequencing. Despite this species' prolonged history of small population size and highly restricted distribution, we demonstrate extensive diversity at MHC DRB with 26 alleles, whereas MHC DQB is dimorphic. We identify four DRB codons, predicted to be involved in antigen binding, that are evolving under adaptive evolution. Our data suggest diversity at DRB may be maintained by balancing selection, consistent with the role of this locus as an antigen-binding region and the species' recent history of mass mortality during a series of bacterial epizootics. Phylogenetic analyses of DQB and DRB sequences from pinnipeds and other carnivores revealed significant allelic diversity, but little phylogenetic depth or structure among pinniped alleles; thus, we could neither confirm nor refute the possibility of trans-species polymorphism in this group. The phylogenetic pattern observed however, suggests some significant evolutionary constraint on these loci in the recent past, with the pattern consistent with that expected following an epizootic event. These data may help further elucidate some of the genetic factors underlying the unusually high susceptibility to bacterial infection of the threatened NZSL, and help us to better understand the extent and pattern of MHC diversity in pinnipeds.
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Affiliation(s)
- A J Osborne
- Centre for Reproduction and Genomics, Department of Anatomy, University of Otago, Dunedin, New Zealand.
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22
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Aguilar JRD, Schut E, Merino S, Martínez J, Komdeur J, Westerdahl H. MHC class II B diversity in blue tits: a preliminary study. Ecol Evol 2013; 3:1878-89. [PMID: 23919136 PMCID: PMC3728931 DOI: 10.1002/ece3.598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 04/17/2013] [Indexed: 12/18/2022] Open
Abstract
In this study, we partly characterize major histocompatibility complex (MHC) class II B in the blue tit (Cyanistes caeruleus). A total of 22 individuals from three different European locations: Spain, The Netherlands, and Sweden were screened for MHC allelic diversity. The MHC genes were investigated using both PCR-based methods and unamplified genomic DNA with restriction fragment length polymorphism (RFLP) and southern blots. A total of 13 different exon 2 sequences were obtained independently from DNA and/or RNA, thus confirming gene transcription and likely functionality of the genes. Nine out of 13 alleles were found in more than one country, and two alleles appeared in all countries. Positive selection was detected in the region coding for the peptide binding region (PBR). A maximum of three alleles per individual was detected by sequencing and the RFLP pattern consisted of 4-7 fragments, indicating a minimum number of 2-4 loci per individual. A phylogenetic analysis, demonstrated that the blue tit sequences are divergent compared to sequences from other passerines resembling a different MHC lineage than those possessed by most passerines studied to date.
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Affiliation(s)
- Juan Rivero-de Aguilar
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC)J. Gutiérrez Abascal 2, E-28006, Madrid, Spain
| | - Elske Schut
- Behavioural Ecology and Self-Organization, The University of GroningenPO Box 11103, 9700 CC, Groningen, The Netherlands
| | - Santiago Merino
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC)J. Gutiérrez Abascal 2, E-28006, Madrid, Spain
| | - Javier Martínez
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de AlcaláAlcalá de Henares, E-28871, Madrid, Spain
| | - Jan Komdeur
- Behavioural Ecology and Self-Organization, The University of GroningenPO Box 11103, 9700 CC, Groningen, The Netherlands
| | - Helena Westerdahl
- Molecular Ecology and Evolution Lab, Ecology Building, Lund UniversitySölvegatan 37, SE-22362, Lund, Sweden
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Yasukochi Y, Kurosaki T, Yoneda M, Koike H, Satta Y. MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus. BMC Evol Biol 2012. [PMID: 23190438 PMCID: PMC3575356 DOI: 10.1186/1471-2148-12-230] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background The major histocompatibility complex (MHC) genes are one of the most important genetic systems in the vertebrate immune response. The diversity of MHC genes may directly influence the survival of individuals against infectious disease. However, there has been no investigation of MHC diversity in the Asiatic black bear (Ursus thibetanus). Here, we analyzed 270-bp nucleotide sequences of the entire exon 2 region of the MHC DQB gene by using 188 samples from the Japanese black bear (Ursus thibetanus japonicus) from 12 local populations. Results Among 185 of 188 samples, we identified 44 MHC variants that encoded 31 different amino acid sequences (allotypes) and one putative pseudogene. The phylogenetic analysis suggests that MHC variants detected from the Japanese black bear are derived from the DQB locus. One of the 31 DQB allotypes, Urth-DQB*01, was found to be common to all local populations. Moreover, this allotype was shared between the black bear on the Asian continent and the Japanese black bear, suggesting that Urth-DQB*01 might have been maintained in the ancestral black bear population for at least 300,000 years. Our findings, from calculating the ratio of non-synonymous to synonymous substitutions, indicate that balancing selection has maintained genetic variation of peptide-binding residues at the DQB locus of the Japanese black bear. From examination of genotype frequencies among local populations, we observed a considerably lower level of observed heterozygosity than expected. Conclusions The low level of observed heterozygosity suggests that genetic drift reduced DQB diversity in the Japanese black bear due to a bottleneck event at the population or species level. The decline of DQB diversity might have been accelerated by the loss of rare variants that have been maintained by negative frequency-dependent selection. Nevertheless, DQB diversity of the black bear appears to be relatively high compared with some other endangered mammalian species. This result suggests that the Japanese black bears may also retain more potential resistance against pathogens than other endangered mammalian species. To prevent further decline of potential resistance against pathogens, a conservation policy for the Japanese black bear should be designed to maintain MHC rare variants in each local population.
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Affiliation(s)
- Yoshiki Yasukochi
- Department of Evolutionary Studies of Biosystems, the Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193, Japan.
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Alasaad S, Fickel J, Rossi L, Sarasa M, BenÃ-tez-Camacho B, Granados JE, Soriguer RC. Applicability of major histocompatibility complex DRB1 alleles as markers to detect vertebrate hybridization: a case study from Iberian ibex × domestic goat in southern Spain. Acta Vet Scand 2012; 54:56. [PMID: 23006678 PMCID: PMC3511808 DOI: 10.1186/1751-0147-54-56] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 09/18/2012] [Indexed: 11/16/2022] Open
Abstract
Background Hybridization between closely related wild and domestic species is of great concern because it can alter the evolutionary integrity of the affected populations. The high allelic variability of Major Histocompatibility Complex (MHC) loci usually excludes them from being used in studies to detect hybridization events. However, if a) the parental species don’t share alleles, and b) one of the parental species possesses an exceptionally low number of alleles (to facilitate analysis), then even MHC loci have the potential to detect hybrids. Results By genotyping the exon2 of the MHC class II DRB1 locus, we were able to detect hybridization between domestic goats (Capra hircus) and free-ranging Iberian ibex (Capra pyrenaica hispanica) by molecular means. Conclusions This is the first documentation of a Capra pyrenaica × Capra hircus hybridization, which presented us the opportunity to test the applicability of MHC loci as new, simple, cost-effective, and time-saving approach to detect hybridization between wild species and their domesticated relatives, thus adding value to MHC genes role in animal conservation and management.
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25
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Barbour EK, Saade MF, Sleiman FT, Hamadeh SK, Mouneimne Y, Kassaifi Z, Kayali G, Harakeh S, Jaber LS, Shaib HA. Optimization of Saanen sperm genes amplification: evaluation of standardized protocols in genetically uncharacterized rural goats reared under a subtropical environment. Trop Anim Health Prod 2012; 44:1513-9. [PMID: 22350811 DOI: 10.1007/s11250-012-0096-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2012] [Indexed: 11/27/2022]
Abstract
The purpose of this research is to optimize quantitatively the amplification of specific sperm genes in reference genomically characterized Saanen goat and to evaluate the standardized protocols applicability on sperms of uncharacterized genome of rural goats reared under subtropical environment for inclusion in future selection programs. The optimization of the protocols in Saanen sperms included three production genes (growth hormone (GH) exons 2, 3, and 4, αS1-casein (CSN1S1), and α-lactalbumin) and two health genes (MHC class II DRB and prion (PrP)). The optimization was based on varying the primers concentrations and the inclusion of a PCR cosolvent (Triton X). The impact of the studied variables on statistically significant increase in the yield of amplicons was noticed in four out of five (80%) optimized protocols, namely in those related to GH, CSN1S1, α-lactalbumin, and PrP genes (P < 0.05). There was no significant difference in the yield of amplicons related to MHC class II DRB gene, regardless of the variables used (P > 0.05). The applicability of the optimized protocols of Saanen sperm genes on amplification of uncharacterized rural goat sperms revealed a 100% success in tested individuals for amplification of GH, CSN1S1, α-lactalbumin, and MHC class II DRB genes and a 75% success for the PrP gene. The significant success in applicability of the Saanen quantitatively optimized protocols to other uncharacterized genome of rural goats allows for their inclusion in future selection, targeting the sustainability of this farming system in a subtropical environment and the improvement of the farmers livelihood.
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Affiliation(s)
- Elie K Barbour
- Animal and Veterinary Sciences Department, Faculty of Agricultural and Food Sciences (FAFS), American University of Beirut (AUB), P.O.Box 11-0236, Beirut, Lebanon.
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Shafer ABA, Fan CW, Cote SD, Coltman DW. (Lack of) Genetic Diversity in Immune Genes Predates Glacial Isolation in the North American Mountain Goat (Oreamnos americanus). J Hered 2012; 103:371-9. [DOI: 10.1093/jhered/esr138] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Ploshnitsa AI, Goltsman ME, Macdonald DW, Kennedy LJ, Sommer S. Impact of historical founder effects and a recent bottleneck on MHC variability in Commander Arctic foxes (Vulpes lagopus). Ecol Evol 2012; 2:165-80. [PMID: 22408734 PMCID: PMC3297186 DOI: 10.1002/ece3.42] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 08/24/2011] [Accepted: 08/26/2011] [Indexed: 11/11/2022] Open
Abstract
Populations of Arctic foxes (Vulpes lagopus) have been isolated on two of the Commander Islands (Bering and Mednyi) from the circumpolar distributed mainland population since the Pleistocene. In 1970-1980, an epizootic outbreak of mange caused a severe population decline on Mednyi Island. Genes of the major histocompatibility complex (MHC) play a primary role in infectious disease resistance. The main objectives of our study were to compare contemporary variation of MHC class II in mainland and island Arctic foxes, and to document the effects of the isolation and the recent bottleneck on MHC polymorphism by analyzing samples from historical and contemporary Arctic foxes. In 184 individuals, we found 25 unique MHC class II DRB and DQB alleles, and identified evidence of balancing selection maintaining allelic lineages over time at both loci. Twenty different MHC alleles were observed in mainland foxes and eight in Bering Island foxes. The historical Mednyi population contained five alleles and all contemporary individuals were monomorphic at both DRB and DQB. Our data indicate that despite positive and diversifying selection leading to elevated rates of amino acid replacement in functionally important antigen-binding sites, below a certain population size, balancing selection may not be strong enough to maintain genetic diversity in functionally important genes. This may have important fitness consequences and might explain the high pathogen susceptibility in some island populations. This is the first study that compares MHC diversity before and after a bottleneck in a wild canid population using DNA from museum samples.
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Kennedy LJ, Randall DA, Knobel D, Brown JJ, Fooks AR, Argaw K, Shiferaw F, Ollier WER, Sillero-Zubiri C, Macdonald DW, Laurenson MK. Major histocompatibility complex diversity in the endangered Ethiopian wolf (Canis simensis). ACTA ACUST UNITED AC 2011; 77:118-25. [PMID: 21214524 DOI: 10.1111/j.1399-0039.2010.01591.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The major histocompatibility complex (MHC) influences immune response to infection and vaccination. In most species, MHC genes are highly polymorphic, but few wild canid populations have been investigated. In Ethiopian wolves, we identified four DLA (dog leucocyte antigen)-DRB1, two DLA-DQA1 and five DQB1 alleles. Ethiopian wolves, the world's rarest canids with fewer than 500 animals worldwide, are further endangered and threatened by rabies. Major rabies outbreaks in the Bale Mountains of southern Ethiopia (where over half of the Ethiopian wolf population is located) have killed over 75% of wolves in the affected sub-populations. In 2004, following a rabies outbreak, 77 wolves were vaccinated, and 19 were subsequently recaptured to monitor the effectiveness of the intervention. Pre- and post-vaccination rabies antibody titres were available for 18 animals, and all of the animals sero-converted after vaccination. We compared the haplotype frequencies of this group of 18 with the post-vaccination antibody titre, and showed that one haplotype was associated with a lower response (uncorrected P < 0.03). In general, Ethiopian wolves probably have an adequate amount of MHC variation to ensure the survival of the species. However, we sampled only the largest Ethiopian wolf population in Bale, and did not take the smaller populations further north into consideration.
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Affiliation(s)
- L J Kennedy
- Centre for Integrated Genomic Medical Research, University of Manchester, Manchester, UK.
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30
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Agudo R, Alcaide M, Rico C, Lemus JA, Blanco G, Hiraldo F, Donázar JA. Major histocompatibility complex variation in insular populations of the Egyptian vulture: inferences about the roles of genetic drift and selection. Mol Ecol 2011; 20:2329-40. [PMID: 21535276 DOI: 10.1111/j.1365-294x.2011.05107.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Insular populations have attracted the attention of evolutionary biologists because of their morphological and ecological peculiarities with respect to their mainland counterparts. Founder effects and genetic drift are known to distribute neutral genetic variability in these demes. However, elucidating whether these evolutionary forces have also shaped adaptive variation is crucial to evaluate the real impact of reduced genetic variation in small populations. Genes of the major histocompatibility complex (MHC) are classical examples of evolutionarily relevant loci because of their well-known role in pathogen confrontation and clearance. In this study, we aim to disentangle the partial roles of genetic drift and natural selection in the spatial distribution of MHC variation in insular populations. To this end, we integrate the study of neutral (22 microsatellites and one mtDNA locus) and MHC class II variation in one mainland (Iberia) and two insular populations (Fuerteventura and Menorca) of the endangered Egyptian vulture (Neophron percnopterus). Overall, the distribution of the frequencies of individual MHC alleles (n=17 alleles from two class II B loci) does not significantly depart from neutral expectations, which indicates a prominent role for genetic drift over selection. However, our results point towards an interesting co-evolution of gene duplicates that maintains different pairs of divergent alleles in strong linkage disequilibrium on islands. We hypothesize that the co-evolution of genes may counteract the loss of genetic diversity in insular demes, maximize antigen recognition capabilities when gene diversity is reduced, and promote the co-segregation of the most efficient allele combinations to cope with local pathogen communities.
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Affiliation(s)
- Rosa Agudo
- Department of Conservation Biology, Doñana Biological Station-CSIC, Avenida Américo Vespucio s/n, E-41092 Sevilla, Spain.
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31
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Castro-Prieto A, Wachter B, Sommer S. Cheetah paradigm revisited: MHC diversity in the world's largest free-ranging population. Mol Biol Evol 2011; 28:1455-68. [PMID: 21183613 PMCID: PMC7187558 DOI: 10.1093/molbev/msq330] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
For more than two decades, the cheetah (Acinonyx jubatus) has been considered a paradigm of disease vulnerability associated with low genetic diversity, particularly at the immune genes of the major histocompatibility complex (MHC). Cheetahs have been used as a classic example in numerous conservation genetics textbooks as well as in many related scientific publications. However, earlier studies used methods with low resolution to quantify MHC diversity and/or small sample sizes. Furthermore, high disease susceptibility was reported only for captive cheetahs, whereas free-ranging cheetahs show no signs of infectious diseases and a good general health status. We examined whether the diversity at MHC class I and class II-DRB loci in 149 Namibian cheetahs was higher than previously reported using single-strand conformation polymorphism analysis, cloning, and sequencing. MHC genes were examined at the genomic and transcriptomic levels. We detected ten MHC class I and four class II-DRB alleles, of which nine MHC class I and all class II-DRB alleles were expressed. Phylogenetic analyses and individual genotypes suggested that the alleles belong to four MHC class I and three class II-DRB putative loci. Evidence of positive selection was detected in both MHC loci. Our study indicated that the low number of MHC class I alleles previously observed in cheetahs was due to a smaller sample size examined. On the other hand, the low number of MHC class II-DRB alleles previously observed in cheetahs was further confirmed. Compared with other mammalian species including felids, cheetahs showed low levels of MHC diversity, but this does not seem to influence the immunocompetence of free-ranging cheetahs in Namibia and contradicts the previous conclusion that the cheetah is a paradigm species of disease vulnerability.
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Affiliation(s)
| | - Bettina Wachter
- Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Simone Sommer
- Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
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Ortego J, Yannic G, Shafer ABA, Mainguy J, Festa-Bianchet M, Coltman DW, Côté SD. Temporal dynamics of genetic variability in a mountain goat (Oreamnos americanus) population. Mol Ecol 2011; 20:1601-11. [PMID: 21366746 DOI: 10.1111/j.1365-294x.2011.05022.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The association between population dynamics and genetic variability is of fundamental importance for both evolutionary and conservation biology. We combined long-term population monitoring and molecular genetic data from 123 offspring and their parents at 28 microsatellite loci to investigate changes in genetic diversity over 14 cohorts in a small and relatively isolated population of mountain goats (Oreamnos americanus) during a period of demographic increase. Offspring heterozygosity decreased while parental genetic similarity and inbreeding coefficients (F(IS) ) increased over the study period (1995-2008). Immigrants introduced three novel alleles into the population and matings between residents and immigrants produced more heterozygous offspring than local crosses, suggesting that immigration can increase population genetic variability. The population experienced genetic drift over the study period, reflected by a reduced allelic richness over time and an 'isolation-by-time' pattern of genetic structure. The temporal decline of individual genetic diversity despite increasing population size probably resulted from a combination of genetic drift due to small effective population size, inbreeding and insufficient counterbalancing by immigration. This study highlights the importance of long-term genetic monitoring to understand how demographic processes influence temporal changes of genetic diversity in long-lived organisms.
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Affiliation(s)
- Joaquín Ortego
- Département de biologie and Centre d'études nordiques, Université Laval, 1045 avenue de Médecine, Québec, Canada.
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Kennedy LJ, Modrell A, Groves P, Wei Z, Single RM, Happ GM. Genetic diversity of the major histocompatibility complex class II in Alaskan caribou herds. Int J Immunogenet 2010; 38:109-19. [PMID: 21054806 DOI: 10.1111/j.1744-313x.2010.00973.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have sampled five different herds of caribou in Alaska to ascertain their major histocompatibility complex (MHC) class II diversity, and to assess whether the herds were significantly different in their MHC class II allele profiles. We complemented the MHC results with data from nine neutral microsatellite markers. The results indicate that while the microsatellites are diverse, there are no significant differences between the herds. However, for the MHC, we have shown that there is diversity at three of the four loci studied, the different herds have significantly different MHC class II allele profiles. It is also clear that although some of the herds have overlapping ranges, they are still different for their MHC class II alleles.
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Affiliation(s)
- L J Kennedy
- Centre for Integrated Genomic Medical Research, University of Manchester, Manchester, UK.
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Worley K, Collet J, Spurgin LG, Cornwallis C, Pizzari T, Richardson DS. MHC heterozygosity and survival in red junglefowl. Mol Ecol 2010; 19:3064-75. [PMID: 20618904 DOI: 10.1111/j.1365-294x.2010.04724.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Genes of the major histocompatibility complex (MHC) form a vital part of the vertebrate immune system and play a major role in pathogen resistance. The extremely high levels of polymorphism observed at the MHC are hypothesised to be driven by pathogen-mediated selection. Although the exact nature of selection remains unclear, three main hypotheses have been put forward; heterozygote advantage, negative frequency-dependence and fluctuating selection. Here, we report the effects of MHC genotype on survival in a cohort of semi-natural red junglefowl (Gallus gallus) that suffered severe mortality as a result of an outbreak of the disease coccidiosis. The cohort was followed from hatching until 250 days of age, approximately the age of sexual maturity in this species, during which time over 80% of the birds died. We show that on average birds with MHC heterozygote genotypes survived infection longer than homozygotes and that this effect was independent of genome-wide heterozygosity, estimated across microsatellite loci. This MHC effect appeared to be caused by a single susceptible haplotype (CD_c) the effect of which was masked in all heterozygote genotypes by other dominant haplotypes. The CD_c homozygous genotype had lower survival than all other genotypes, but CD_c heterozygous genotypes had survival probabilities equal to the most resistant homozygote genotype. Importantly, no heterozygotes conferred greater resistance than the most resistant homozygote genotype, indicating that the observed survival advantage of MHC heterozygotes was the product of dominant, rather than overdominant processes. This pattern and effect of MHC diversity in our population could reflect the processes ongoing in similarly small, fragmented natural populations.
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Affiliation(s)
- Kirsty Worley
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
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35
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Variety matters: adaptive genetic diversity and parasite load in two mouse opossums from the Brazilian Atlantic forest. CONSERV GENET 2010. [DOI: 10.1007/s10592-010-0093-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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36
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Shafer ABA, Côté SD, Coltman DW. HOT SPOTS OF GENETIC DIVERSITY DESCENDED FROM MULTIPLE PLEISTOCENE REFUGIA IN AN ALPINE UNGULATE. Evolution 2010; 65:125-38. [DOI: 10.1111/j.1558-5646.2010.01109.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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37
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Liu JX, Ely B. Evolution of an MHC class Ia gene fragment in four North American Morone species. JOURNAL OF FISH BIOLOGY 2010; 76:1984-1994. [PMID: 20557651 DOI: 10.1111/j.1095-8649.2010.02588.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A nucleotide sequence analysis of a fragment of a Morone MHC class Ia gene detected high levels of polymorphism in striped bass Morone saxatilis, white perch Morone americana and yellow bass Morone mississippiensis. Extremely low levels of MHC diversity, however, were detected in white bass Morone chrysops, suggesting the possibility of a severe population bottleneck for this species.
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Affiliation(s)
- J-X Liu
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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38
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Shafer AB, Hall JC. Placing the mountain goat: A total evidence approach to testing alternative hypotheses. Mol Phylogenet Evol 2010; 55:18-25. [DOI: 10.1016/j.ympev.2010.01.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 12/01/2009] [Accepted: 01/15/2010] [Indexed: 12/24/2022]
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Radwan J, Biedrzycka A, Babik W. Does reduced MHC diversity decrease viability of vertebrate populations? BIOLOGICAL CONSERVATION 2010; 143:537-544. [PMID: 32226082 PMCID: PMC7092871 DOI: 10.1016/j.biocon.2009.07.026] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 07/09/2009] [Accepted: 07/27/2009] [Indexed: 05/12/2023]
Abstract
Loss of genetic variation may render populations more vulnerable to pathogens due to inbreeding depression and depletion of variation in genes responsible for immunity against parasites. Here we review the evidence for the significance of variation in genes of the Major Histocompatibility Complex (MHC) for conservation efforts. MHC molecules present pathogen-derived antigens to the effector cells of the immune system and thus trigger the adaptive immune response. Some MHC genes are the most variable functional genes in the vertebrate genome. Their variation is clearly of adaptive significance and there is considerable evidence that its maintenance is mainly due to balancing selection imposed by pathogens. However, while the evidence for selection shaping MHC variation on the historical timescale is compelling, a correlation between levels of MHC variation and variation at neutral loci is often observed, indicating that on a shorter timescale drift also substantially affects MHC, leading to depletion of MHC diversity. The evidence that the loss of MHC variation negatively affects population survival is so far equivocal and difficult to separate from effects of general inbreeding. Some species with depleted MHC variation seem to be particularly susceptible to infection, but other species thrive and expand following severe bottlenecks that have drastically limited their MHC variation. However, while the latter demonstrate that MHC variation is not always critical for population survival, these species may in fact represent rare examples of survival despite of the loss of MHC variation. There is clearly a compelling need for data that would disclose the possible consequences of MHC diversity for population viability. In particular, we need more data on the impact of MHC allelic richness on the abundance of parasites or prevalence of disease in populations, while controlling for the role of general inbreeding. Before such evidence accumulates, captive breeding programs and other conservation measures aimed at inbreeding avoidance should be favoured over those protecting only MHC variation, especially since inbreeding avoidance programs would usually conserve both types of genetic diversity simultaneously.
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Affiliation(s)
- Jacek Radwan
- Institute of Nature Conservation, Polish Academy of Sciences, Al. Mickiewicza 33, 31-120 Kraków, Poland
| | - Aleksandra Biedrzycka
- Institute of Nature Conservation, Polish Academy of Sciences, Al. Mickiewicza 33, 31-120 Kraków, Poland
| | - Wiesław Babik
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, Poland
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MAINGUY JULIEN, CÔTÉ STEEVED, COLTMAN DAVIDW. Multilocus heterozygosity, parental relatedness and individual fitness components in a wild mountain goat,Oreamnos americanuspopulation. Mol Ecol 2009; 18:2297-306. [DOI: 10.1111/j.1365-294x.2009.04197.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Babik W, Pabijan M, Arntzen JW, Cogâlniceanu D, Durka W, Radwan J. Long-term survival of a urodele amphibian despite depleted major histocompatibility complex variation. Mol Ecol 2009; 18:769-81. [PMID: 19207255 DOI: 10.1111/j.1365-294x.2008.04057.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- W Babik
- Department of Community Ecology, Helmholtz Centre for Environmental Research-UFZ, Theodor-Lieser-Str 4, 06120 Halle/Saale, Germany.
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Fernández-de-Mera IG, Vicente J, Pérez de la Lastra JM, Mangold AJ, Naranjo V, Fierro Y, de la Fuente J, Gortázar C. Reduced major histocompatibility complex class II polymorphism in a hunter-managed isolated Iberian red deer population. J Zool (1987) 2009. [DOI: 10.1111/j.1469-7998.2008.00524.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Vassilakos D, Natoli A, Dahlheim M, Hoelzel AR. Balancing and directional selection at exon-2 of the MHC DQB1 locus among populations of odontocete cetaceans. Mol Biol Evol 2009; 26:681-9. [PMID: 19126865 DOI: 10.1093/molbev/msn296] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The diversity of exon-2 (peptide-binding region) of the DQB1 locus (Class II, major histocompatibility complex, MHC) was investigated on an extended sample of populations of three focal cetacean species (two sibling delphinid species and another in the same family). We tested the hypothesis that dolphin populations with a worldwide distribution across different habitats and geographic regions will be under differential selective pressure by comparing DQB1 variation with variation at neutral markers and by investigating putative functional residues within the exon-2 sequence at the population level. Variation at the DQB1 locus was not correlated to neutral differentiation (assessed by comparison with microsatellite DNA markers), and overall F(ST) values were significantly lower for the MHC locus, consistent with expectations for balancing selection. Measures of heterozygosity and d(n)/d(s) ratios were also consistent with balancing selection. However, outliers in the F(ST) comparisons and the analysis of putative functional residues suggested incidences of directional selection in local populations.
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Affiliation(s)
- Demetrios Vassilakos
- School of Biological and Biomedical Sciences, University of Durham, United Kingdom
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