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Wojczulanis-Jakubas K, Hoover B, Jakubas D, Fort J, Grémillet D, Gavrilo M, Zielińska S, Zagalska-Neubauer M. Diversity of major histocompatibility complex of II B gene and mate choice in a monogamous and long-lived seabird, the Little Auk (Alle alle). PLoS One 2024; 19:e0304275. [PMID: 38865310 PMCID: PMC11168636 DOI: 10.1371/journal.pone.0304275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 05/09/2024] [Indexed: 06/14/2024] Open
Abstract
The major histocompatibility complex (MHC) plays a key role in the adaptive immune system of vertebrates, and is known to influence mate choice in many species. In birds, the MHC has been extensively examined but mainly in galliforms and passerines while other taxa that represent specific ecological and evolutionary life-histories, like seabirds, are underexamined. Here, we characterized diversity of MHC Class II B exon 2 in a colonial pelagic seabird, the Little Auk (or Dovekie Alle alle). We further examined whether MHC variation could be maintained through balancing selection and disassortative mating. We found high polymorphism at the genotyped MHC fragment, characterizing 99 distinct alleles across 140 individuals from three populations. The alleles frequencies exhibited a similar skewed distribution in both sexes, with the four most commonly occurring alleles representing approximately 35% of allelic variation. The results of a Bayesian site-by-site selection analysis suggest evidence of balancing selection and no direct evidence for MHC-dependent disassortative mating preferences in the Little Auk. The latter result might be attributed to the high overall polymorphism of the examined fragment, which itself may be maintained by the large population size of the species.
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Affiliation(s)
| | - Brian Hoover
- Farallon Institute, Petaluma, California, United States of America
| | - Dariusz Jakubas
- Department of Vertebrate Ecology and Zoology, Faculty of Biology, University of Gdansk, Gdansk, Poland
| | - Jérôme Fort
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS – La Rochelle University, 17000 La Rochelle, France
| | - David Grémillet
- Excellence Chair Nouvelle Aquitaine - CEBC UMR 7372 CNRS, La Rochelle Université, Villiers-en-Bois, France & FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, South Africa
| | | | - Sylwia Zielińska
- Department of Molecular Biology, Faculty of Biology, University of Gdansk, Gdansk, Poland
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Hipfner JM, Prill MM, Studholme KR, Domalik AD, Tucker S, Jardine C, Maftei M, Wright KG, Beck JN, Bradley RW, Carle RD, Good TP, Hatch SA, Hodum PJ, Ito M, Pearson SF, Rojek NA, Slater L, Watanuki Y, Will AP, Bindoff AD, Crossin GT, Drever MC, Burg TM. Geolocator tagging links distributions in the non-breeding season to population genetic structure in a sentinel North Pacific seabird. PLoS One 2020; 15:e0240056. [PMID: 33166314 PMCID: PMC7652296 DOI: 10.1371/journal.pone.0240056] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 09/17/2020] [Indexed: 12/15/2022] Open
Abstract
We tested the hypothesis that segregation in wintering areas is associated with population differentiation in a sentinel North Pacific seabird, the rhinoceros auklet (Cerorhinca monocerata). We collected tissue samples for genetic analyses on five breeding colonies in the western Pacific Ocean (Japan) and on 13 colonies in the eastern Pacific Ocean (California to Alaska), and deployed light-level geolocator tags on 12 eastern Pacific colonies to delineate wintering areas. Geolocator tags were deployed previously on one colony in Japan. There was strong genetic differentiation between populations in the eastern vs. western Pacific Ocean, likely due to two factors. First, glaciation over the North Pacific in the late Pleistocene might have forced a southward range shift that historically isolated the eastern and western populations. And second, deep-ocean habitat along the northern continental shelf appears to act as a barrier to movement; abundant on both sides of the North Pacific, the rhinoceros auklet is virtually absent as a breeder in the Aleutian Islands and Bering Sea, and no tagged birds crossed the North Pacific in the non-breeding season. While genetic differentiation was strongest between the eastern vs. western Pacific, there was also extensive differentiation within both regional groups. In pairwise comparisons among the eastern Pacific colonies, the standardized measure of genetic differentiation (FꞌST) was negatively correlated with the extent of spatial overlap in wintering areas. That result supports the hypothesis that segregation in the non-breeding season is linked to genetic structure. Philopatry and a neritic foraging habit probably also contribute to the structuring. Widely distributed, vulnerable to anthropogenic stressors, and exhibiting extensive genetic structure, the rhinoceros auklet is fully indicative of the scope of the conservation challenges posed by seabirds.
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Affiliation(s)
- J. Mark Hipfner
- Wildlife Research Division, Environment and Climate Change Canada, Delta, British Columbia, Canada
- * E-mail:
| | - Marie M. Prill
- Department of Biology, University of Lethbridge, Lethbridge, Alberta, Canada
| | | | - Alice D. Domalik
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Strahan Tucker
- Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | | | - Mark Maftei
- Wildlife Research Division, Environment and Climate Change Canada, Delta, British Columbia, Canada
| | - Kenneth G. Wright
- Wildlife Research Division, Environment and Climate Change Canada, Delta, British Columbia, Canada
| | - Jessie N. Beck
- Oikonos Ecosystems Knowledge, Santa Cruz, California, United States of America
| | - Russell W. Bradley
- Point Blue Conservation Science, Petaluma, California, United States of America
| | - Ryan D. Carle
- Oikonos Ecosystems Knowledge, Santa Cruz, California, United States of America
| | - Thomas P. Good
- Northwest Fisheries Science Centre, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Seattle, Washington, United States of America
| | - Scott A. Hatch
- Institute for Seabird Research and Conservation, Anchorage, Alaska, United States of America
| | - Peter J. Hodum
- Department of Biology, University of Puget Sound, Tacoma, Washington, United States of America
| | - Motohiro Ito
- Department of Applied Biosciences, Toyo University, Bunkyō-ku, Japan
| | - Scott F. Pearson
- Washington Department of Fish and Wildlife, Olympia, Washington, United States of America
| | - Nora A. Rojek
- United States Fish and Wildlife Service, Homer, Alaska, United States of America
| | - Leslie Slater
- United States Fish and Wildlife Service, Homer, Alaska, United States of America
| | - Yutaka Watanuki
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
| | - Alexis P. Will
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Aidan D. Bindoff
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Tasmania, Australia
| | - Glenn T. Crossin
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Mark C. Drever
- Wildlife Research Division, Environment and Climate Change Canada, Delta, British Columbia, Canada
| | - Theresa M. Burg
- Department of Biology, University of Lethbridge, Lethbridge, Alberta, Canada
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Cruz-López M, Fernández G, Hipperson H, Palacios E, Cavitt J, Galindo-Espinosa D, Gómez Del Angel S, Pruner R, Gonzalez O, Burke T, Küpper C. Allelic diversity and patterns of selection at the major histocompatibility complex class I and II loci in a threatened shorebird, the Snowy Plover (Charadrius nivosus). BMC Evol Biol 2020; 20:114. [PMID: 32912143 PMCID: PMC7488298 DOI: 10.1186/s12862-020-01676-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 08/20/2020] [Indexed: 12/02/2022] Open
Abstract
Background Understanding the structure and variability of adaptive loci such as the major histocompatibility complex (MHC) genes is a primary research goal for evolutionary and conservation genetics. Typically, classical MHC genes show high polymorphism and are under strong balancing selection, as their products trigger the adaptive immune response in vertebrates. Here, we assess the allelic diversity and patterns of selection for MHC class I and class II loci in a threatened shorebird with highly flexible mating and parental care behaviour, the Snowy Plover (Charadrius nivosus) across its broad geographic range. Results We determined the allelic and nucleotide diversity for MHC class I and class II genes using samples of 250 individuals from eight breeding population of Snowy Plovers. We found 40 alleles at MHC class I and six alleles at MHC class II, with individuals carrying two to seven different alleles (mean 3.70) at MHC class I and up to two alleles (mean 1.45) at MHC class II. Diversity was higher in the peptide-binding region, which suggests balancing selection. The MHC class I locus showed stronger signatures of both positive and negative selection than the MHC class II locus. Most alleles were present in more than one population. If present, private alleles generally occurred at very low frequencies in each population, except for the private alleles of MHC class I in one island population (Puerto Rico, lineage tenuirostris). Conclusion Snowy Plovers exhibited an intermediate level of diversity at the MHC, similar to that reported in other Charadriiformes. The differences found in the patterns of selection between the class I and II loci are consistent with the hypothesis that different mechanisms shape the sequence evolution of MHC class I and class II genes. The rarity of private alleles across populations is consistent with high natal and breeding dispersal and the low genetic structure previously observed at neutral genetic markers in this species.
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Affiliation(s)
- Medardo Cruz-López
- Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, Cd. México, Mexico.
| | - Guillermo Fernández
- Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Apartado Postal 811, 82040, Mazatlán, Sinaloa, Mexico
| | - Helen Hipperson
- NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Eduardo Palacios
- Centro de Investigación Científica y de Educación Superior de Ensenada, Unidad La Paz, Miraflores 334, Col. Bellavista, 23050, La Paz, Baja California Sur, Mexico
| | - John Cavitt
- Avian Ecology Laboratory Department of Zoology, Weber State University, Ogden, UT, 84408, USA
| | - Daniel Galindo-Espinosa
- Departamento Académico de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, Carretera al Sur km 5.5, A.P. 19-B, 23080, La Paz, B.C.S., Mexico
| | - Salvador Gómez Del Angel
- Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, Cd. México, Mexico
| | - Raya Pruner
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, Panama City, FL, USA
| | - Oscar Gonzalez
- Grupo Aves del Perú, Gómez del Carpio 135, Barrio Medico, 34, Lima, Peru.,Department of Natural Sciences, Emmanuel College, Franklin Springs, GA, 30369, USA
| | - Terry Burke
- NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Clemens Küpper
- Max Planck Institute for Ornithology, Eberhard-Gwinner-Strasse, 82319, Seewiesen, Germany.
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Hoover B, Alcaide M, Jennings S, Sin SYW, Edwards SV, Nevitt GA. Ecology can inform genetics: Disassortative mating contributes to MHC polymorphism in Leach's storm-petrels (Oceanodroma leucorhoa). Mol Ecol 2018; 27:3371-3385. [PMID: 30010226 DOI: 10.1111/mec.14801] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/31/2018] [Accepted: 06/20/2018] [Indexed: 01/03/2023]
Abstract
Studies of MHC-based mate choice in wild populations often test hypotheses on species exhibiting female choice and male-male competition, which reflects the general prevalence of females as the choosy sex in natural systems. Here, we examined mutual mate-choice patterns in a small burrow-nesting seabird, the Leach's storm-petrel (Oceanodroma leucorhoa), using the major histocompatibility complex (MHC). The life history and ecology of this species are extreme: both partners work together to fledge a single chick during the breeding season, a task that requires regularly travelling hundreds of kilometres to and from foraging grounds over a 6- to 8-week provisioning period. Using a 5-year data set unprecedented for this species (n = 1078 adults and 925 chicks), we found a positive relationship between variation in the likelihood of female reproductive success and heterozygosity at Ocle-DAB2, a MHC class IIB locus. Contrary to previous reports rejecting disassortative mating as a mechanism for maintaining genetic polymorphism in this species, here we show that males make significant disassortative mate-choice decisions. Variability in female reproductive success suggests that the most common homozygous females (Ocle-DAB2*01/Ocle-DAB2*01) may be physiologically disadvantaged and, therefore, less preferred as lifelong partners for choosy males. The results from this study support the role of mate choice in maintaining high levels of MHC variability in a wild seabird species and highlight the need to incorporate a broader ecological framework and sufficient sample sizes into studies of MHC-based mating patterns in wild populations in general.
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Affiliation(s)
- Brian Hoover
- Graduate Group in Ecology, University of California, Davis, California
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
| | - Miguel Alcaide
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Sarah Jennings
- Graduate Group in Ecology, University of California, Davis, California
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
| | - Simon Yung Wa Sin
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
| | - Gabrielle A Nevitt
- Graduate Group in Ecology, University of California, Davis, California
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
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Elbers JP, Clostio RW, Taylor SS. Neutral Genetic Processes Influence MHC Evolution in Threatened Gopher Tortoises (Gopherus polyphemus). J Hered 2017; 108:515-523. [PMID: 28387863 DOI: 10.1093/jhered/esx034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 04/04/2017] [Indexed: 11/12/2022] Open
Abstract
Levels of adaptive genetic variation influence how species deal with environmental and ecological change, but these levels are frequently inferred using neutral genetic markers. Major histocompatibility complex (MHC) genes play a key role in the adaptive branch of the immune system and have been used extensively to estimate levels of adaptive genetic variation. Parts of the peptide binding region, sites where MHC molecules directly interact with pathogen and self-proteins, were sequenced from a MHC class I (95/441 tortoises) and class II (245/441 tortoises) gene in threatened and nonthreatened populations of gopher tortoises (Gopherus polyphemus), and adaptive genetic variation at MHC genes was compared to neutral genetic variation derived from 10 microsatellite loci (441 tortoises). Genetic diversity at the MHC class II locus and microsatellites was greater in populations in the nonthreatened portion of the gopher tortoise's range (MHC class II difference in mean A = 8.11, AR = 0.79, HO = 0.51, and HE = 0.16; microsatellite difference in mean A = 1.05 and AR = 0.47). Only MHC class II sequences showed evidence of positive selection (dN/dS > 1, Z = 1.81, P = 0.04). Historical gene flow as estimated with Migrate-N was greater than recent migration estimated with BayesAss, suggesting that populations were better connected in the past when habitat was less fragmented. MHC genetic differentiation was correlated with microsatellite differentiation (Mantel r = 0.431, P = 0.001) suggesting neutral genetic processes are influencing MHC evolution, and advantageous MHC alleles could be lost due to genetic drift.
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Affiliation(s)
- Jean P Elbers
- School of Renewable Natural Resources, Louisiana State University and AgCenter, 227 RNR Bldg., Baton Rouge, LA 70803; and Department of Biology, University of Louisiana at Lafayette, Lafayette, LA
| | - Rachel W Clostio
- School of Renewable Natural Resources, Louisiana State University and AgCenter, 227 RNR Bldg., Baton Rouge, LA 70803; and Department of Biology, University of Louisiana at Lafayette, Lafayette, LA
| | - Sabrina S Taylor
- School of Renewable Natural Resources, Louisiana State University and AgCenter, 227 RNR Bldg., Baton Rouge, LA 70803; and Department of Biology, University of Louisiana at Lafayette, Lafayette, LA
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Cutrera AP, Mora MS. Selection on MHC in a Context of Historical Demographic Change in 2 Closely Distributed Species of Tuco-tucos (Ctenomys australis and C. talarum). J Hered 2017; 108:628-639. [PMID: 28605534 DOI: 10.1093/jhered/esx054] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 06/07/2017] [Indexed: 11/12/2022] Open
Abstract
Selection necessarily acts within the same current and historical demographic framework as neutral evolutionary processes, and the outcome of the interplay between these forces may vary according to their relative strength. In this study, we compare the variation at a major histocompatibility complex (MHC) locus (DRB exon 2), typically subject to strong diversifying selection, and mitochondrial diversity (D-loop) across populations encompassing the entire distribution of 2 species of South American subterranean rodents: Ctenomys australis and C. talarum (tuco-tucos). Although these species are parapatric along most of their distribution, historically they have followed distinct demographic trajectories associated with sea level changes during the Quaternary. We surveyed 8 populations of C. australis and 15 of C. talarum, from which we analyzed 70 and 212 D-loop haplotypes and 91 and 346 DRB genotypes, respectively. Both species have gone through a recent demographic expansion; however, the signal of this process only encompasses the entire distribution of one of the species: C. australis. While balancing selection on MHC in C. talarum-enhanced DRB diversity at the local level compared to D-loop, although not promoting divergence among populations, in C. australis local diversifying selection may have driven higher population differentiation at DRB than at D-loop. Our findings reinforce the idea that the relative strength of selection acting on MHC genes varies spatially and temporally within and among species, even between species using the same macrohabitat and exposed to similar immune challenges.
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Affiliation(s)
- Ana Paula Cutrera
- Instituto de Investigaciones Marinas y Costeras, CONICET - Universidad Nacional de Mar del Plata, Funes 3350, Mar del Plata (7600), Argentina
| | - Matías Sebastián Mora
- Instituto de Investigaciones Marinas y Costeras, CONICET - Universidad Nacional de Mar del Plata, Funes 3350, Mar del Plata (7600), Argentina
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Historical gene flow and profound spatial genetic structure among golden pheasant populations suggested by multi-locus analysis. Mol Phylogenet Evol 2017; 110:93-103. [PMID: 28286102 DOI: 10.1016/j.ympev.2017.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 12/06/2016] [Accepted: 03/06/2017] [Indexed: 12/23/2022]
Abstract
Major histocompatibility complex (MHC) is a good marker system for geographical genetics since they are functional genes in the immune system that are likely to affect the fitness of the individual, and the survival and evolutionary potential of a population in a changing environment. Golden pheasant (Chrysolophus pictus) is a wild Phasianidae distributed in central and north China. In this study, we used a locus-specific genotyping technique for MHC IIB genes of golden pheasant. Combining with microsatellites (simple sequence repeat, SSR) and mitochondrial DNA (mtDNA) D-loop region, we investigated the demographic history and illuminate genetic structure of this bird in detail. SYR (south of Yangtze river) - NYR (north of Yangtze river) lineages, separated by Yangtze River, were defined in genetic structure of MHC IIB. NYR was supposed as refuge during glacial period, suggested by diversity parameters and more ancient alleles in this region. Based on this hypothesis, there was gene flow from NYR to SYR, which was proved by three pieces of evidence: (1) distinct demographic histories of SYR (kept stable) and NYR (experienced expansion); (2) specific affiliation of LC in genetic structure of SSR and MHC genes; (3) significant gene flow from NYR to SYR. Moreover, we also found balancing selection by combination of three Grouping A2's regions (SC, QL and North) into one in Grouping B4 (NYR) and no pattern of isolation by distance (IBD) found in MHC IIB, whereas for SSR we found a relatively strong and significant IBD. Several mechanisms in the evolution of MHC IIB genes, including recombination, historically positive selection, trans-species evolution and concerted evolution, were shown by molecular and phylogenetic analysis. Overall these results suggest the Yangtze River was inferred to be a geological barrier for this avian and NYR might experience population expansion, which invaded into a neighboring region. This study contributes to the understanding of the effects of geographic features on contemporary patterns of genetic variation in the golden pheasant in China, and helps us to define the adaptive unite (AU) for this avian.
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Li D, Sun K, Zhao Y, Lin A, Li S, Jiang Y, Feng J. Polymorphism in the major histocompatibility complex (MHC class II B) genes of the Rufous-backed Bunting ( Emberiza jankowskii). PeerJ 2017; 5:e2917. [PMID: 28149689 PMCID: PMC5270597 DOI: 10.7717/peerj.2917] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 12/16/2016] [Indexed: 11/23/2022] Open
Abstract
Genetic diversity is one of the pillars of conservation biology research. High genetic diversity and abundant genetic variation in an organism may be suggestive of capacity to adapt to various environmental changes. The major histocompatibility complex (MHC) is known to be highly polymorphic and plays an important role in immune function. It is also considered an ideal model system to investigate genetic diversity in wildlife populations. The Rufous-backed Bunting (Emberiza jankowskii) is an endangered species that has experienced a sharp decline in both population and habitat size. Many historically significant populations are no longer present in previously populated regions, with only three breeding populations present in Inner Mongolia (i.e., the Aolunhua, Gahaitu and Lubei557 populations). Efforts focused on facilitating the conservation of the Rufous-backed Bunting (Emberiza jankowskii) are becoming increasingly important. However, the genetic diversity of E. jankowskii has not been investigated. In the present study, polymorphism in exon 2 of the MHCIIB of E. jankowskii was investigated. This polymorphism was subsequently compared with a related species, the Meadow Bunting (Emberiza cioides). A total of 1.59 alleles/individual were detected in E. jankowskii and 1.73 alleles/individual were identified in E. cioides. The maximum number of alleles per individual from the three E. jankowskii populations suggest the existence of at least three functional loci, while the maximum number of alleles per individual from the three E. cioides populations suggest the presence of at least four functional loci. Two of the alleles were shared between the E. jankowskii and E. cioides. Among the 12 unique alleles identified in E. jankowskii, 10.17 segregating sites per allele were detected, and the nucleotide diversity was 0.1865. Among the 17 unique alleles identified in E. cioides, eight segregating sites per allele were detected, and the nucleotide diversity was 0.1667. Overall, compared to other passerine birds, a relatively low level of MHC polymorphism was revealed in E. jankowskii, which was similar to that in E. cioides. Positive selection was detected by PAML/SLAC/FEL analyses in the region encoding the peptide-binding region in both species, and no recombination was detected. Phylogenetic analysis showed that the alleles from E. jankowskii and E. cioides belong to the same clade and the two species shared similar alleles, suggesting the occurrence of a trans-species polymorphism between the two Emberiza species.
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Affiliation(s)
- Dan Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China; College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Keping Sun
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University , Changchun , China
| | - Yunjiao Zhao
- College of Animal Science and Technology, Jilin Agricultural University , Changchun , China
| | - Aiqing Lin
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University , Changchun , China
| | - Shi Li
- College of Animal Science and Technology, Jilin Agricultural University , Changchun , China
| | - Yunlei Jiang
- College of Animal Science and Technology, Jilin Agricultural University , Changchun , China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University , Changchun , China
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Rico Y, Ethier DM, Davy CM, Sayers J, Weir RD, Swanson BJ, Nocera JJ, Kyle CJ. Spatial patterns of immunogenetic and neutral variation underscore the conservation value of small, isolated American badger populations. Evol Appl 2016; 9:1271-1284. [PMID: 27877205 PMCID: PMC5108218 DOI: 10.1111/eva.12410] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 07/14/2016] [Indexed: 12/29/2022] Open
Abstract
Small and isolated populations often exhibit low genetic diversity due to drift and inbreeding, but may simultaneously harbour adaptive variation. We investigate spatial distributions of immunogenetic variation in American badger subspecies (Taxidea taxus), as a proxy for evaluating their evolutionary potential across the northern extent of the species' range. We compared genetic structure of 20 microsatellites and the major histocompatibility complex (MHC DRB exon 2) to evaluate whether small, isolated populations show low adaptive polymorphism relative to large and well-connected populations. Our results suggest that gene flow plays a prominent role in shaping MHC polymorphism across large spatial scales, while the interplay between gene flow and selection was stronger towards the northern peripheries. The similarity of MHC alleles within subspecies relative to their neutral genetic differentiation suggests that adaptive divergence among subspecies can be maintained despite ongoing gene flow along subspecies boundaries. Neutral genetic diversity was low in small relative to large populations, but MHC diversity within individuals was high in small populations. Despite reduced neutral genetic variation, small and isolated populations harbour functional variation that likely contribute to the species evolutionary potential at the northern range. Our findings suggest that conservation approaches should focus on managing adaptive variation across the species range rather than protecting subspecies per se.
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Affiliation(s)
- Yessica Rico
- Forensic Science DepartmentTrent UniversityPeterboroughONCanada
- Natural Resources DNA Profiling and Forensics CentreTrent UniversityPeterboroughONCanada
- Present address: CONACYTInstituto de Ecología A.C.Centro Regional del BajíoAvenida Lázaro Cárdenas 253PátzcuaroMichoacán61600México
| | - Danielle M. Ethier
- Ontario Badger ProjectGuelphONCanada
- Department of Integrative BiologyUniversity of GuelphGuelphONCanada
| | - Christina M. Davy
- Forensic Science DepartmentTrent UniversityPeterboroughONCanada
- Natural Resources DNA Profiling and Forensics CentreTrent UniversityPeterboroughONCanada
| | | | - Richard D. Weir
- Ecosystems Protection & Sustainability BranchMinistry of EnvironmentVictoriaBCCanada
| | | | - Joseph J. Nocera
- Wildlife Research and Monitoring SectionMinistry of Natural Resources & ForestryPeterboroughONCanada
| | - Christopher J. Kyle
- Forensic Science DepartmentTrent UniversityPeterboroughONCanada
- Natural Resources DNA Profiling and Forensics CentreTrent UniversityPeterboroughONCanada
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Population genetic diversity and geographical differentiation of MHC class II DAB genes in the vulnerable Chinese egret (Egretta eulophotes). CONSERV GENET 2016. [DOI: 10.1007/s10592-016-0876-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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11
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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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12
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Grueber CE. Comparative genomics for biodiversity conservation. Comput Struct Biotechnol J 2015; 13:370-5. [PMID: 26106461 PMCID: PMC4475778 DOI: 10.1016/j.csbj.2015.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 05/13/2015] [Accepted: 05/15/2015] [Indexed: 12/31/2022] Open
Abstract
Genomic approaches are gathering momentum in biology and emerging opportunities lie in the creative use of comparative molecular methods for revealing the processes that influence diversity of wildlife. However, few comparative genomic studies are performed with explicit and specific objectives to aid conservation of wild populations. Here I provide a brief overview of comparative genomic approaches that offer specific benefits to biodiversity conservation. Because conservation examples are few, I draw on research from other areas to demonstrate how comparing genomic data across taxa may be used to inform the characterisation of conservation units and studies of hybridisation, as well as studies that provide conservation outcomes from a better understanding of the drivers of divergence. A comparative approach can also provide valuable insight into the threatening processes that impact rare species, such as emerging diseases and their management in conservation. In addition to these opportunities, I note areas where additional research is warranted. Overall, comparing and contrasting the genomic composition of threatened and other species provide several useful tools for helping to preserve the molecular biodiversity of the global ecosystem.
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Lillie M, Grueber CE, Sutton JT, Howitt R, Bishop PJ, Gleeson D, Belov K. Selection on MHC class II supertypes in the New Zealand endemic Hochstetter's frog. BMC Evol Biol 2015; 15:63. [PMID: 25886729 PMCID: PMC4415247 DOI: 10.1186/s12862-015-0342-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/27/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The New Zealand native frogs, family Leiopelmatidae, are among the most archaic in the world. Leiopelma hochstetteri (Hochstetter's frog) is a small, semi-aquatic frog with numerous, fragmented populations scattered across New Zealand's North Island. We characterized a major histocompatibility complex (MHC) class II B gene (DAB) in L. hochstetteri from a spleen transcriptome, and then compared its diversity to neutral microsatellite markers to assess the adaptive genetic diversity of five populations ("evolutionarily significant units", ESUs). RESULTS L. hochstetteri possessed very high MHC diversity, with 74 DAB alleles characterized. Extremely high differentiation was observed at the DAB locus, with only two alleles shared between populations, a pattern that was not reflected in the microsatellites. Clustering analysis on putative peptide binding residues of the DAB alleles indicated four functional supertypes, all of which were represented in 4 of 5 populations, albeit at different frequencies. Otawa was an exception to these observations, with only two DAB alleles present. CONCLUSIONS This study of MHC diversity highlights extreme population differentiation at this functional locus. Supertype differentiation was high among populations, suggesting spatial and/or temporal variation in selection pressures. Low DAB diversity in Otawa may limit this population's adaptive potential to future pathogenic challenges.
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Affiliation(s)
- Mette Lillie
- Faculty of Veterinary Science, University of Sydney, Sydney, Australia.
| | - Catherine E Grueber
- Faculty of Veterinary Science, University of Sydney, Sydney, Australia.
- San Diego Zoo Global, San Diego, USA.
| | - Jolene T Sutton
- Department of Biology, University of Hawai'i at Mānoa, Honolulu, USA.
| | | | - Phillip J Bishop
- Department of Biology, University of Otago, Dunedin, New Zealand.
| | - Dianne Gleeson
- Landcare Research, Auckland, New Zealand.
- Institute for Applied Ecology, University of Canberra, Bruce, Australia.
| | - Katherine Belov
- Faculty of Veterinary Science, University of Sydney, Sydney, Australia.
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