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Yan J, Song C, Liang J, La Y, Lai J, Pan R, Huang Z, Li B, Zhang P. Moderate Genetic Diversity of MHC Genes in an Isolated Small Population of Black-and-White Snub-Nosed Monkeys ( Rhinopithecus bieti). Animals (Basel) 2024; 14:2276. [PMID: 39123802 PMCID: PMC11310952 DOI: 10.3390/ani14152276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 08/01/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024] Open
Abstract
Genetic diversity is an essential indicator that echoes the natural selection and environmental adaptation of a species. Isolated small populations are vulnerable to genetic drift, inbreeding, and limited gene flow; thus, assessing their genetic diversity is critical in conservation. In this study, we studied the genetic diversity of black-and-white snub-nosed monkeys (Rhinopithecus bieti) using neutral microsatellites and five adaptive major histocompatibility complex (MHC) genes. Two DQA1 alleles, two DQB1 alleles, two DRB1 alleles, two DRB5 alleles, and three DPB1 alleles were isolated from a population. The results indicate that neutral microsatellites demonstrate a high degree of heterozygosity and polymorphism, while adaptive MHC genes display a high degree of heterozygosity and moderate polymorphism. The results also show that balancing selection has prominently influenced the MHC diversity of the species during evolution: (1) significant positive selection is identified at several amino acid sites (primarily at and near antigen-binding sites) of the DRB1, DRB5, and DQB1 genes; (2) phylogenetic analyses display the patterns of trans-species evolution for all MHC loci. This study provides valuable genetic diversity insights into black-and-white snub-nosed monkeys, which dwell at the highest altitude and have experienced the harshest environmental selection of all primates globally since the Pleistocene. Such results provide valuable scientific evidence and a reference for making or amending conservation strategies for this endangered primate species.
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Affiliation(s)
- Jibing Yan
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
| | - Chunmei Song
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
| | - Jiaqi Liang
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
| | - Yanni La
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
| | - Jiandong Lai
- Baima Snow Mountain National Nature Reserve Administrative Bureau, Diqing 674500, China;
| | - Ruliang Pan
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
- International Center of Biodiversity and Primat Conservation, Dali University, Dali 671003, China
- School of Human Sciences, The University of Western Australia, Perth, WA 6009, Australia
| | - Zhipang Huang
- Institute of Eastern-Himalaya Biodiversity Research, Dali University, Dali 671003, China;
| | - Baoguo Li
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
- Shaanxi Institute of Zoology, Xi’an 710032, China
- College of Life Science, Yanan University, Yanan 710032, China
| | - Pei Zhang
- Shaanxi Key Laboratory of Animal Conservation, College of Life Sciences, Northwest University, Xi’an 710069, China; (J.Y.); (C.S.); (J.L.); (Y.L.); (R.P.)
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2
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Minias P, Podlaszczuk P, Indykiewicz P, Ledwoń M, Nowakowski J, Chyb A, Janiszewski T. Genetic variation at innate and adaptive immune genes - contrasting patterns of differentiation and local adaptation in a wild gull. Heredity (Edinb) 2023; 131:282-291. [PMID: 37553491 PMCID: PMC10539538 DOI: 10.1038/s41437-023-00645-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/15/2023] [Accepted: 07/30/2023] [Indexed: 08/10/2023] Open
Abstract
Immunogenetic variation in natural vertebrate populations is expected to respond to spatial and temporal fluctuations in pathogen assemblages. While spatial heterogeneity in pathogen-driven selection enhances local immunogenetic adaptations and population divergence, different immune genes may yield contrasting responses to the environment. Here, we investigated population differentiation at the key pathogen recognition genes of the innate and adaptive immune system in a colonial bird species, the black-headed gull Chroicocephalus ridibundus. We assessed genetic variation at three toll-like receptor (TLR) genes (innate immunity) and the major histocompatibility complex (MHC) class I and II genes (adaptive immunity) in gulls from seven colonies scattered across Poland. As expected, we found much greater polymorphism at the MHC than TLRs. Population differentiation at the MHC class II, but not MHC-I, was significantly stronger than at neutral microsatellite loci, suggesting local adaptation. This could reflect spatial variation in the composition of extracellular parasite communities (e.g., helminths), possibly driven by sharp differences in habitat structure between colonies. Despite contrasting patterns of population differentiation, both MHC classes showed similar regimes of diversifying selection. Some significant population differentiation was also observed at TLRs, suggesting that innate immune receptors may respond to fine-scale spatial variation in pathogen pressure, although this pattern could have been enhanced by drift. Our results suggested that local adaptation at the pathogen recognition immune genes can be maintained at relatively small or moderate spatial scales in species with high dispersal potential and they highlighted the complexity of immunogenetic responses of animals to heterogeneous environments.
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Affiliation(s)
- Piotr Minias
- Department of Biodiversity Studies and Bioeducation, Faculty of Biology and Environmental Protection, University of Łódź, Banacha 1/3, 90-237, Łódź, Poland.
| | - Patrycja Podlaszczuk
- Department of Biodiversity Studies and Bioeducation, Faculty of Biology and Environmental Protection, University of Łódź, Banacha 1/3, 90-237, Łódź, Poland
| | - Piotr Indykiewicz
- Department of Biology and Animal Environment, Faculty of Animal Breeding and Biology, Bydgoszcz University of Science and Technology, Mazowiecka 28, 85-084, Bydgoszcz, Poland
| | - Mateusz Ledwoń
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016, Kraków, Poland
| | - Jacek Nowakowski
- Department of Ecology and Environmental Protection, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Plac Łódzki 3, 10-727, Olsztyn, Poland
| | - Amelia Chyb
- Department of Biodiversity Studies and Bioeducation, Faculty of Biology and Environmental Protection, University of Łódź, Banacha 1/3, 90-237, Łódź, Poland
| | - Tomasz Janiszewski
- Department of Biodiversity Studies and Bioeducation, Faculty of Biology and Environmental Protection, University of Łódź, Banacha 1/3, 90-237, Łódź, Poland
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3
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Przesmycka K, Herdegen-Radwan M, Phillips KP, Mohammed RS, Radwan J. The quest for good genes: Epigamic traits, fitness, MHC and multilocus heterozygosity in the guppy. Mol Ecol 2023; 32:5055-5070. [PMID: 37492990 DOI: 10.1111/mec.17083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/29/2023] [Accepted: 07/11/2023] [Indexed: 07/27/2023]
Abstract
The 'good genes' hypothesis for the evolution of male secondary sexual traits poses that female preferences for such traits are driven by indirect genetic benefits. However, support for the hypothesis remains ambiguous, and, in particular, the genetic basis for the benefits has rarely been investigated. Here, we use seminatural populations of Trinidadian guppies to investigate whether sexually selected traits (orange, black and iridescent colouration, gonopodium length and body size) predict fitness measured as the number of grandoffspring, a metric that integrates across fitness components and sexes. Furthermore, we tested whether two potential sources of genetic benefits-major histocompatibility complex (MHC) genotypes and multilocus heterozygosity (MLH)-are significant predictors of fitness and of the size of sexually selected traits. We found a significant, nonlinear effect of the area of black pigmentation and male body size on the number of grandoffspring, suggesting stabilizing selection on black area, and nonlinear selection favouring small body size. MLH was heritable (h2 = 0.14) and significantly predicted the number of grandoffspring, indicating the potential for genetic benefits based on heterozygosity. We also found support for local heterozygosity effects, which may reflect a noneven distribution of genetic load across the genome. MHC genotype was not significantly associated with any tested fitness component, or with the load of Gyrodactylus parasites. Neither MHC nor MLH was significant predictor of sexually selected traits. Overall, our results highlight the role of heterozygosity in determining fitness, but do not provide support for male sexually selected traits being indicators of genetic quality.
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Affiliation(s)
- Karolina Przesmycka
- Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | | | - Karl P Phillips
- Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
- School of Biological Earth and Environmental Sciences, University College Cork, Cork, Ireland
- Canadian Rivers Institute, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Ryan S Mohammed
- Department of Biology, Auburn University, Auburn, Alabama, USA
| | - Jacek Radwan
- Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
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4
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Lam DK, Frantz AC, Burke T, Geffen E, Sin SYW. Both selection and drift drive the spatial pattern of adaptive genetic variation in a wild mammal. Evolution 2023; 77:221-238. [PMID: 36626810 DOI: 10.1093/evolut/qpac014] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 10/03/2022] [Accepted: 11/04/2022] [Indexed: 01/12/2023]
Abstract
The major histocompatibility complex (MHC) has been intensively studied for the relative effects of different evolutionary forces in recent decades. Pathogen-mediated balancing selection is generally thought to explain the high polymorphism observed in MHC genes, but it is still unclear to what extent MHC diversity is shaped by selection relative to neutral drift. In this study, we genotyped MHC class II DRB genes and 15 neutral microsatellite loci across 26 geographic populations of European badgers (Meles meles) covering most of their geographic range. By comparing variation of microsatellite and diversity of MHC at different levels, we demonstrate that both balancing selection and drift have shaped the evolution of MHC genes. When only MHC allelic identity was investigated, the spatial pattern of MHC variation was similar to that of microsatellites. By contrast, when functional aspects of the MHC diversity (e.g., immunological supertypes) were considered, balancing selection appears to decrease genetic structuring across populations. Our comprehensive sampling and analytical approach enable us to conclude that the likely mechanisms of selection are heterozygote advantage and/or rare-allele advantage. This study is a clear demonstration of how both balancing selection and genetic drift simultaneously affect the evolution of MHC genes in a widely distributed wild mammal.
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Affiliation(s)
- Derek Kong Lam
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Alain C Frantz
- Musée National d'Histoire Naturelle, Luxembourg, Luxembourg
| | - Terry Burke
- Ecology and Evolutionary Biology, School of Biosciences, University of Sheffield, Sheffield, United Kingdom
| | - Eli Geffen
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Simon Yung Wa Sin
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
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5
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Li X, Liu T, Li A, Xiao Y, Sun K, Feng J. Diversifying selection and climatic effects on major histocompatibility complex class
II
gene diversity in the greater horseshoe bat. Evol Appl 2023; 16:688-704. [PMID: 36969140 PMCID: PMC10033860 DOI: 10.1111/eva.13528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 01/09/2023] Open
Abstract
Heterogeneous pathogenic stress can shape major histocompatibility complex (MHC) diversity by influencing the functional plasticity of the immune response. Therefore, MHC diversity could reflect environmental stress, demonstrating its importance in uncovering the mechanisms of adaptive genetic variation. In this study, we combined neutral microsatellite loci, an immune-related MHC II-DRB locus, and climatic factors to unravel the mechanisms affecting the diversity and genetic differentiation of MHC genes in the greater horseshoe bat (Rhinolophus ferrumequinum), a species with a wide geographical distribution that has three distinct genetic lineages in China. First, increased genetic differentiation at the MHC locus among populations compared using microsatellites indicated diversifying selection. Second, the genetic differentiation of MHC and microsatellites were significantly correlated, suggesting that demographic processes exist. However, MHC genetic differentiation was significantly correlated with geographical distance among populations, even after controlling for the neutral markers, suggesting a major effect of selection. Third, although the MHC genetic differentiation was larger than that for microsatellites, there was no significant difference in the genetic differentiation between the two markers among genetic lineages, indicating the effect of balancing selection. Fourth, combined with climatic factors, MHC diversity and supertypes showed significant correlations with temperature and precipitation, but not with the phylogeographic structure of R. ferrumequinum, suggesting an effect of local adaptation driven by climate on MHC diversity. Moreover, the number of MHC supertypes varied between populations and lineages, suggesting regional characteristics and support for local adaptation. Taken together, the results of our study provide insights into the adaptive evolutionary driving forces at different geographic scales in R. ferrumequinum. In addition, climate factors may have played a vital role in driving adaptive evolution in this species.
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Affiliation(s)
- Xiaolin Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
- Key Laboratory of Vegetation Ecology, Ministry of Education Changchun China
| | - Tong Liu
- College of Life Science, Jilin Agricultural University Changchun China
| | - Aoqiang Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Yanhong Xiao
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Keping Sun
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
- Key Laboratory of Vegetation Ecology, Ministry of Education Changchun China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
- College of Life Science, Jilin Agricultural University Changchun China
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6
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Otto M, Zheng Y, Wiehe T. Recombination, selection and the evolution of tandem gene arrays. Genetics 2022; 221:6572811. [PMID: 35460227 PMCID: PMC9252282 DOI: 10.1093/genetics/iyac052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/17/2022] [Indexed: 11/16/2022] Open
Abstract
Multigene families—immunity genes or sensory receptors, for instance—are often subject to diversifying selection. Allelic diversity may be favored not only through balancing or frequency-dependent selection at individual loci but also by associating different alleles in multicopy gene families. Using a combination of analytical calculations and simulations, we explored a population genetic model of epistatic selection and unequal recombination, where a trade-off exists between the benefit of allelic diversity and the cost of copy abundance. Starting from the neutral case, where we showed that gene copy number is Gamma distributed at equilibrium, we derived also the mean and shape of the limiting distribution under selection. Considering a more general model, which includes variable population size and population substructure, we explored by simulations mean fitness and some summary statistics of the copy number distribution. We determined the relative effects of selection, recombination, and demographic parameters in maintaining allelic diversity and shaping the mean fitness of a population. One way to control the variance of copy number is by lowering the rate of unequal recombination. Indeed, when encoding recombination by a rate modifier locus, we observe exactly this prediction. Finally, we analyzed the empirical copy number distribution of 3 genes in human and estimated recombination and selection parameters of our model.
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Affiliation(s)
- Moritz Otto
- Institut für Genetik, Universität zu Köln, Zülpicher Straße 47a, 50674 Köln, Germany
| | - Yichen Zheng
- Institut für Genetik, Universität zu Köln, Zülpicher Straße 47a, 50674 Köln, Germany
| | - Thomas Wiehe
- Institut für Genetik, Universität zu Köln, Zülpicher Straße 47a, 50674 Köln, Germany
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7
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Pikus E, Włodarczyk R, Jedlikowski J, Minias P. Urbanization processes drive divergence at the major histocompatibility complex in a common waterbird. PeerJ 2021; 9:e12264. [PMID: 34707940 PMCID: PMC8500109 DOI: 10.7717/peerj.12264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/16/2021] [Indexed: 11/20/2022] Open
Abstract
Urban sprawl is one of the most common landscape alterations occurring worldwide, and there is a growing list of species that are recognised to have adapted to urban life. To be successful, processes of urban colonization by wildlife require a broad spectrum of phenotypic (e.g., behavioural or physiological) adjustments, but evidence for genetic adaptations is much scarcer. One hypothesis proposes that different pathogen-driven selective pressures between urban and non-urban landscapes leads to adaptations in host immune genes. Here, we examined urbanization-related differentiation at the key pathogen-recognition genes of vertebrate adaptive immunity-the major histocompatibility complex (MHC)-in a common waterbird, the Eurasian coot (Fulica atra). Samples were collected from an old urban population (established before the 1950s), a new urban population (established in the 2000s), and two rural populations from central Poland. We found strong significant divergence (as measured with Jost's D) at the MHC class II between the old urban population and the remaining (new urban and rural) populations. Also, there was a moderate, but significant divergence at the MHC between the new urban population and two rural populations, while no divergence was found between the two rural populations. The total number of MHC alleles and the number of private (population-specific) MHC alleles was lower in old urban populations, as compared to the rural ones. These patterns of differentiation at the MHC were not consistent with patterns found for neutral genetic markers (microsatellites), which showed few differences between the populations. Our results indicate that MHC allele composition depended on the level of anthropogenic disturbance and the time which passed since urban colonization, possibly due to the processes of genotype sorting and local adaptation. As such, our study contributes to the understanding of genetic mechanisms associated with urbanization processes in wildlife.
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Affiliation(s)
- Ewa Pikus
- Department of Biodiversity Studies and Bioeducation, University of Łódź, Łódź, Poland
| | - Radosław Włodarczyk
- Department of Biodiversity Studies and Bioeducation, University of Łódź, Łódź, Poland
| | - Jan Jedlikowski
- Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Piotr Minias
- Department of Biodiversity Studies and Bioeducation, University of Łódź, Łódź, Poland
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8
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Li X, Liu T, Li A, Zhang L, Dai W, Jin L, Sun K, Feng J. Genetic polymorphisms and the independent evolution of major histocompatibility complex class II‐
DRB
in sibling bat species
Rhinolophus episcopus
and
Rhinolophus siamensis. J ZOOL SYST EVOL RES 2021. [DOI: 10.1111/jzs.12462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Xiaolin Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Tong Liu
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Aoqiang Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Lin Zhang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Wentao Dai
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Longru Jin
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Keping Sun
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
- Key Laboratory of Vegetation Ecology Ministry of Education Changchun China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
- College of Life Science Jilin Agricultural University Changchun China
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9
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Smallbone W, Ellison A, Poulton S, van Oosterhout C, Cable J. Depletion of MHC supertype during domestication can compromise immunocompetence. Mol Ecol 2020; 30:736-746. [PMID: 33274493 PMCID: PMC7898906 DOI: 10.1111/mec.15763] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 11/23/2020] [Accepted: 11/26/2020] [Indexed: 12/27/2022]
Abstract
The major histocompatibility complex (MHC) plays an important role in infectious disease resistance. The presence of certain MHC alleles and functionally similar groups of MHC alleles (i.e., supertypes) has been associated with resistance to particular parasite species. Farmed and domesticated fish stocks are often depleted in their MHC alleles and supertype diversity, possibly as a consequence of artificial selection for desirable traits, inbreeding (loss of heterozygosity), genetic drift (loss of allelic diversity) and/or reduced parasite biodiversity. Here we quantify the effects of depletion of MHC class II genotype and supertype variation on resistance to the parasite Gyrodactylus turnbulli in guppies (Poecilia reticulata). Compared to the descendants of wild‐caught guppies, ornamental fish had a significantly reduced MHC variation (i.e., the numbers of MHC alleles and supertypes per individual, and per population). In addition, ornamental fish were significantly more susceptible to G. turnbulli infections, accumulating peak intensity 10 times higher than that of their wildtype counterparts. Four out of 13 supertypes were associated with a significantly reduced parasite load, and the presence of some supertypes had a dramatic effect on the intensity of infection. Remarkably, the ornamental and wildtype fish differed in the supertypes that were associated with parasite resistance. Analysis with a genetic algorithm showed that resistance‐conferring supertypes of the wildtype and ornamental fish shared two unique amino acids in the peptide‐binding region of the MHC that were not found in any other alleles. These data show that the supertype demarcation captures some, but not all, of the variation in the immune function of the alleles. This study highlights the importance of managing functional MHC diversity in livestock, and suggests there might be some immunological redundancy among MHC supertypes.
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Affiliation(s)
| | - Amy Ellison
- School of Biosciences, Cardiff University, Cardiff, UK
| | - Simon Poulton
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Cock van Oosterhout
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Joanne Cable
- School of Biosciences, Cardiff University, Cardiff, UK
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10
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Balancing selection versus allele and supertype turnover in MHC class II genes in guppies. Heredity (Edinb) 2020; 126:548-560. [PMID: 32985616 DOI: 10.1038/s41437-020-00369-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 09/03/2020] [Accepted: 09/07/2020] [Indexed: 01/10/2023] Open
Abstract
Selection pressure from parasites is thought to be a major force shaping the extreme polymorphism of the major histocompatibility complex (MHC) genes, but the modes and consequences of selection remain unclear. Here, we analyse MHC class II and microsatellite diversity in 16 guppy (Poecilia reticulata) populations from two islands (Trinidad and Tobago) that have been separated for at least 10 ky. Within-population MHC diversity was high, but allele sharing was limited within islands and even lower between islands, suggesting relatively fast turnover of alleles. Allelic lineages strongly supported in phylogenetic analyses tended to be island-specific, suggesting rapid lineage sorting, and an expansion of an allelic lineage private to Tobago was observed. New alleles appear to be generated locally at a detectably high frequency. We did not detect a consistent signature of local adaptation, but FST outlier analysis suggested that balancing selection may be the more general process behind spatial variation in MHC allele frequencies in this system, particularly within Trinidad. We found no evidence for divergent allele advantage within populations, or for decreased genetic structuring of MHC supertypes compared to MHC alleles. The dynamic and complex nature of MHC evolution we observed in guppies, coupled with some evidence for balancing selection shaping MHC allele frequencies, are consistent with Red Queen processes of host-parasite coevolution.
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11
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Okano M, Miyamae J, Suzuki S, Nishiya K, Katakura F, Kulski JK, Moritomo T, Shiina T. Identification of Novel Alleles and Structural Haplotypes of Major Histocompatibility Complex Class I and DRB Genes in Domestic Cat ( Felis catus) by a Newly Developed NGS-Based Genotyping Method. Front Genet 2020; 11:750. [PMID: 32760428 PMCID: PMC7375346 DOI: 10.3389/fgene.2020.00750] [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: 04/02/2020] [Accepted: 06/23/2020] [Indexed: 12/24/2022] Open
Abstract
The major histocompatibility complex (MHC) is a highly polymorphic and duplicated genomic region that encodes transplantation and immune regulatory molecules. Although it is well-known that particular MHC allelic polymorphisms and haplotypes are genetically relate to immune-mediated diseases detailed information of the cat MHC (Feline Leukocyte Antigen; FLA) genetic and haplotypic structure and diversity is limited in comparison to humans and many other species. In this study, to better understand the degree and types of allele and allelic haplotype diversity of FLA-class I (FLA-I) and FLA-DRB loci in domestic cats, we identified six expressible FLA-I loci in peripheral white blood cells by in silico estimation of the coding exons and NGS-based amplicon sequencing using five unrelated cats. We then used a newly developed NGS-based genotyping method to genotype and annotate 32 FLA-I and 16 FLA-DRB sequences in two families of 20 domestic cats. A total of 14 FLA-I and seven FLA-DRB were identified as novel polymorphic sequences. Phylogenetic analyses grouped the sequences into six FLA-I (FLA-E/H/K, FLA-A, FLA-J, FLA-L, FLA-O and a tentatively named FLA-E/H/K_Rec) and four FLA-DRB (FLA-DRB1, FLA-DRB3, FLA-DRB4, and FLA-DRB5) lineages. Pedigree analysis of two cat families revealed eight distinct FLA structural haplotypes (Class I - DRB) with five to eight FLA-I and two to three FLA-DRB transcribed loci per haplotype. It is evident that the eight FLA haplotypes were generated by gene duplications and deletions, and rearrangements by genetic recombination with the accumulation and/or inheritance of novel polymorphisms. These findings are useful for further genetic diversity analysis and disease association studies among cat breeds and in veterinary medicine.
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Affiliation(s)
- Masaharu Okano
- Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Jiro Miyamae
- Faculty of Veterinary Medicine, Okayama University of Science, Imabari, Japan
| | - Shingo Suzuki
- Division of Basic Medical Science and Molecular Medicine, Department of Molecular Life Science, Tokai University, Isehara, Japan
| | - Kohei Nishiya
- Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Fumihiko Katakura
- Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Jerzy K Kulski
- Division of Basic Medical Science and Molecular Medicine, Department of Molecular Life Science, Tokai University, Isehara, Japan.,Faculty of Health and Medical Sciences, UWA Medical School, The University of Western Australia, Perth, WA, Australia
| | - Tadaaki Moritomo
- Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Takashi Shiina
- Division of Basic Medical Science and Molecular Medicine, Department of Molecular Life Science, Tokai University, Isehara, Japan
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12
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Radwan J, Babik W, Kaufman J, Lenz TL, Winternitz J. Advances in the Evolutionary Understanding of MHC Polymorphism. Trends Genet 2020; 36:298-311. [DOI: 10.1016/j.tig.2020.01.008] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/13/2020] [Accepted: 01/14/2020] [Indexed: 12/26/2022]
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13
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Gaigher A, Burri R, San-Jose LM, Roulin A, Fumagalli L. Lack of statistical power as a major limitation in understanding MHC-mediated immunocompetence in wild vertebrate populations. Mol Ecol 2019; 28:5115-5132. [PMID: 31614047 DOI: 10.1111/mec.15276] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 10/07/2019] [Accepted: 10/11/2019] [Indexed: 01/09/2023]
Abstract
Disentangling the sources of variation in developing an effective immune response against pathogens is of major interest to immunoecology and evolutionary biology. To date, the link between immunocompetence and genetic variation at the major histocompatibility complex (MHC) has received little attention in wild animals, despite the key role of MHC genes in activating the adaptive immune system. Although several studies point to a link between MHC and immunocompetence, negative findings have also been reported. Such disparate findings suggest that limited statistical power might be affecting studies on this topic, owing to insufficient sample sizes and/or a generally small effect of MHC on the immunocompetence of wild vertebrates. To clarify this issue, we investigated the link between MHC variation and seven immunocompetence proxies in a large sample of barn owls and estimated the effect sizes and statistical power of this and published studies on this topic. We found that MHC poorly explained variation in immunocompetence of barn owls, with small-to-moderate associations between MHC and immunocompetence in owls (effect size: .1 ≥ r ≤ .3) similar to other vertebrates studied to date. Such small-to-moderate effects were largely associated with insufficient power, which was only sufficient (>0.8) to detect moderate-to-large effect sizes (r ≥ .3). Thus, studies linking MHC variation with immunocompetence in wild populations are underpowered to detect MHC effects, which are likely to be of generally small magnitude. Larger sample sizes (>200) will be required to achieve sufficient power in future studies aiming to robustly test for a link between MHC variation and immunocompetence.
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Affiliation(s)
- Arnaud Gaigher
- Department of Ecology and Evolution, Laboratory for Conservation Biology, Biophore, University of Lausanne, Lausanne, Switzerland.,Department of Computational Biology, Génopode, University of Lausanne, Lausanne, Switzerland.,CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão, Portugal
| | - Reto Burri
- Department of Population Ecology, Institute of Ecology & Evolution, Friedrich Schiller University Jena, Jena, Germany
| | - Luis M San-Jose
- Department of Ecology and Evolution, Biophore, University of Lausanne, Lausanne, Switzerland.,Laboratoire Évolution & Diversité Biologique, UMR 5174, CNRS, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Alexandre Roulin
- Department of Ecology and Evolution, Biophore, University of Lausanne, Lausanne, Switzerland
| | - Luca Fumagalli
- Department of Ecology and Evolution, Laboratory for Conservation Biology, Biophore, University of Lausanne, Lausanne, Switzerland
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14
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Talarico L, Babik W, Marta S, Pietrocini V, Mattoccia M. MHC structuring and divergent allele advantage in a urodele amphibian: a hierarchical multi-scale approach. Heredity (Edinb) 2019; 123:593-607. [PMID: 31036951 PMCID: PMC6972932 DOI: 10.1038/s41437-019-0221-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/31/2019] [Accepted: 03/31/2019] [Indexed: 12/27/2022] Open
Abstract
Proteins encoded by extraordinarily polymorphic major histocompatibility complex (MHC) genes are involved in the adaptive immune response. Balancing selection is believed to maintain MHC polymorphism in the long term, although neutral processes also play a role in shaping MHC diversity. However, the relative contribution of these processes is poorly understood. Here we characterized MHC class II variation of a low-dispersal, pond-breeding newt (Triturus carnifex) over a restricted, geographically structured area. We aimed to (1) evaluate the contribution of selection and neutral processes to shaping MHC diversity at two geographic scales, and (2) test for signatures of divergent allele advantage (DAA), which is a potentially important mechanism of balancing selection. The dominant role of selection in shaping MHC variation was suggested by the lack of correlation between MHC and neutral (microsatellite) variation. Although most variation occurred within populations for both types of markers, they differed in the extent of structuring at the two spatial scales. MHC structuring was more pronounced at local scales, suggesting the role of local selection, while structuring was not detectable at a larger scale, possibly due to the effect of balancing selection. Microsatellites showed the opposite pattern. As expected under DAA, the observed genotypes combined more sequence diversity than expected under a random association of alleles. Thus, DAA may contribute to maintaining MHC polymorphism, which is ancient, as supported by signatures of historical positive selection and trans-species polymorphism. Our results point to the importance of a multi-scale approach in studying MHC variation, especially in low-dispersal taxa, which are genetically structured at fine spatial scales.
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Affiliation(s)
- Lorenzo Talarico
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, Rome, 00133, Italy.
| | - Wiesław Babik
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Kraków, 30-387, Poland
| | - Silvio Marta
- Department of Environmental Sciences and Policy, University of Milan, Via G. Celoria 26, Milan, 20133, Italy
| | - Venusta Pietrocini
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, Rome, 00133, Italy
| | - Marco Mattoccia
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, Rome, 00133, Italy
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15
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Castillo JA, Agathos SN. A genome-wide scan for genes under balancing selection in the plant pathogen Ralstonia solanacearum. BMC Evol Biol 2019; 19:123. [PMID: 31208326 PMCID: PMC6580516 DOI: 10.1186/s12862-019-1456-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 06/10/2019] [Indexed: 02/07/2023] Open
Abstract
Background Plant pathogens are under significant selective pressure by the plant host. Consequently, they are expected to have adapted to this condition or contribute to evading plant defenses. In order to acquire long-term fitness, plant bacterial pathogens are usually forced to maintain advantageous genetic diversity in populations. This strategy ensures that different alleles in the pathogen’s gene pool are maintained in a population at frequencies larger than expected under neutral evolution. This selective process, known as balancing selection, is the subject of this work in the context of a common bacterial phytopathogen. We performed a genome-wide scan of Ralstonia solanacearum species complex, an aggressive plant bacterial pathogen that shows broad host range and causes a devastating disease called ‘bacterial wilt’. Results Using a sliding window approach, we analyzed 57 genomes from three phylotypes of the R. solanacearum species complex to detect signatures of balancing selection. A total of 161 windows showed extreme values in three summary statistics of population genetics: Tajima’s D, θw and Fu & Li’s D*. We discarded any confounding effects due to demographic events by means of coalescent simulations of genetic data. The prospective windows correspond to 78 genes with known function that map in any of the two main replicons (1.7% of total number of genes). The candidate genes under balancing selection are related to primary metabolism and other basal activities (51.3%) or directly associated to virulence (48.7%), the latter being involved in key functions targeted to dismantle plant defenses or to participate in critical stages in the pathogenic process. Conclusions We identified various genes under balancing selection that play a significant role in basic metabolism as well as in virulence of the R. solanacearum species complex. These genes are useful to understand and monitor the evolution of bacterial pathogen populations and emerge as potential candidates for future treatments to induce specific plant immune responses. Electronic supplementary material The online version of this article (10.1186/s12862-019-1456-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- José A Castillo
- School of Biological Sciences and Engineering, Yachay Tech University, Hacienda San Jose s/n and Proyecto Yachay, Urcuquí, Ecuador.
| | - Spiros N Agathos
- School of Biological Sciences and Engineering, Yachay Tech University, Hacienda San Jose s/n and Proyecto Yachay, Urcuquí, Ecuador
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16
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Sagonas K, Runemark A, Antoniou A, Lymberakis P, Pafilis P, Valakos ED, Poulakakis N, Hansson B. Selection, drift, and introgression shape MHC polymorphism in lizards. Heredity (Edinb) 2019; 122:468-484. [PMID: 30258107 PMCID: PMC6460769 DOI: 10.1038/s41437-018-0146-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 07/27/2018] [Accepted: 08/09/2018] [Indexed: 01/12/2023] Open
Abstract
The major histocompatibility complex (MHC) has long served as a model for the evolution of adaptive genetic diversity in wild populations. Pathogen-mediated selection is thought to be a main driver of MHC diversity, but it remains elusive to what degree selection shapes MHC diversity in complex biogeographical scenarios where other evolutionary processes (e.g. genetic drift and introgression) may also be acting. Here we focus on two closely related green lizard species, Lacerta trilineata and L. viridis, to address the evolutionary forces acting on MHC diversity in populations with different biogeographic structure. We characterized MHC class I exon 2 and exon 3, and neutral diversity (microsatellites), to study the relative importance of selection, drift, and introgression in shaping MHC diversity. As expected, positive selection was a significant force shaping the high diversity of MHC genes in both species. Moreover, introgression significantly increased MHC diversity in mainland populations, with a primary direction of gene flow from L. viridis to L. trilineata. Finally, we found significantly fewer MHC alleles in island populations, but maintained MHC sequence and functional diversity, suggesting that positive selection counteracted the effect of drift. Overall, our data support that different evolutionary processes govern MHC diversity in different biogeographical scenarios: positive selection occurs broadly while introgression acts in sympatry and drift when the population sizes decrease.
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Affiliation(s)
- K Sagonas
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.
- Department of Human and Animal Physiology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistimioupoli Zografou, 15784, Athens, Greece.
| | - A Runemark
- Department of Biology, Lund University, Ecology Building, SE-223 62, Lund, Sweden
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - A Antoniou
- Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Gournes Pediados, 71003, Heraklion, Crete, Greece
| | - P Lymberakis
- Natural History Museum of Crete, School of Sciences and Engineering, University of Crete, 71409, Heraklion, Crete, Greece
| | - P Pafilis
- Department of Zoology and Marine Biology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistimioupoli Zografou, 15784, Athens, Greece
| | - E D Valakos
- Department of Human and Animal Physiology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistimioupoli Zografou, 15784, Athens, Greece
| | - N Poulakakis
- Natural History Museum of Crete, School of Sciences and Engineering, University of Crete, 71409, Heraklion, Crete, Greece
- Department of Biology, School of Sciences and Engineering, University of Crete, Vasilika Vouton, 71003, Heraklion, Crete, Greece
| | - B Hansson
- Department of Biology, Lund University, Ecology Building, SE-223 62, Lund, Sweden
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17
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Pérez-Espona S, Goodall-Copestake WP, Savirina A, Bobovikova J, Molina-Rubio C, Pérez-Barbería FJ. First assessment of MHC diversity in wild Scottish red deer populations. EUR J WILDLIFE RES 2019. [DOI: 10.1007/s10344-019-1254-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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Hacking J, Bradford T, Pierce K, Gardner M. De novo genotyping of the major histocompatibility complex in an Australian dragon lizard, Ctenophorus decresii. T ROY SOC SOUTH AUST 2018. [DOI: 10.1080/03721426.2018.1542259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Jessica Hacking
- College of Science and Engineering, Flinders University, Bedford Park, Australia
| | - Tessa Bradford
- College of Science and Engineering, Flinders University, Bedford Park, Australia
- Evolutionary Biology Unit, South Australian Museum, Adelaide, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Kelly Pierce
- College of Science and Engineering, Flinders University, Bedford Park, Australia
| | - Michael Gardner
- College of Science and Engineering, Flinders University, Bedford Park, Australia
- Evolutionary Biology Unit, South Australian Museum, Adelaide, Australia
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19
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Fijarczyk A, Dudek K, Niedzicka M, Babik W. Balancing selection and introgression of newt immune-response genes. Proc Biol Sci 2018; 285:20180819. [PMID: 30111606 PMCID: PMC6111169 DOI: 10.1098/rspb.2018.0819] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 07/18/2018] [Indexed: 12/20/2022] Open
Abstract
The importance of interspecific introgression as a source of adaptive variation is increasingly recognized. Theory predicts that beneficial genetic variants cross species boundaries easily even when interspecific hybridization is rare and gene flow is strongly constrained throughout the genome. However, it remains unclear whether certain classes of genes are particularly prone to adaptive introgression. Genes affected by balancing selection (BS) may constitute such a class, because forms of BS that favour novel, initially rare alleles, should facilitate introgression. We tested this hypothesis in hybridizing newts by comparing 13 genes with signatures of BS, in particular an excess of common non-synonymous polymorphisms, to the genomic background (154 genes). Parapatric hybridizing taxa were less differentiated in BS candidate genes than more closely related allopatric lineages, while the opposite was observed in the control genes. Coalescent and forward simulations that explored neutral and BS scenarios under isolation and migration showed that processes other than differential gene flow are unlikely to account for this pattern. We conclude that BS, probably involving a form of novel allele advantage, promotes introgression. This mechanism may be a source of adaptively relevant variation in hybridizing species over prolonged periods.
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Affiliation(s)
- Anna Fijarczyk
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland
- Institut de Biologie Intégrative et des Systèmes, Département de Biologie, Université Laval, 1030, Avenue de la Médecine, Québec, Canada G1V 0A6
| | - Katarzyna Dudek
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland
| | - Marta Niedzicka
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland
| | - Wiesław Babik
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland
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20
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Mable BK, Brysting AK, Jørgensen MH, Carbonell AKZ, Kiefer C, Ruiz-Duarte P, Lagesen K, Koch MA. Adding Complexity to Complexity: Gene Family Evolution in Polyploids. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00114] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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21
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Small-scale intraspecific patterns of adaptive immunogenetic polymorphisms and neutral variation in Lake Superior lake trout. Immunogenetics 2017; 70:53-66. [PMID: 28547520 DOI: 10.1007/s00251-017-0996-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 04/26/2017] [Indexed: 10/19/2022]
Abstract
Many fishes express high levels of intraspecific variability, often linked to resource partitioning. Several studies show that a species' evolutionary trajectory of adaptive divergence can undergo reversals caused by changes in its environment. Such a reversal in neutral genetic and morphological variation among lake trout Salvelinus namaycush ecomorphs appears to be underway in Lake Superior. However, a water depth gradient in neutral genetic divergence was found to be associated with intraspecific diversity in the lake. To investigate patterns of adaptive immunogenetic variation among lake trout ecomorphs, we used Illumina high-throughput sequencing. The population's genetic structure of the major histocompatibility complex (MHC Class IIβ exon 2) and 18 microsatellite loci were compared to disentangle neutral and selective processes at a small geographic scale. Both MHC and microsatellite variation were partitioned more by water depth stratum than by ecomorph. Several metrics showed strong clustering by water depth in MHC alleles, but not microsatellites. We report a 75% increase in the number of MHC alleles shared between the predominant shallow and deep water ecomorphs since a previous lake trout MHC study at the same locale (c. 1990s data). This result is consistent with the reverse speciation hypothesis, although adaptive MHC polymorphisms persist along an ecological gradient. Finally, results suggested that the lake trout have multiple copies of the MHC II locus consistent with a historic genomic duplication event. Our findings indicated that conservation approaches for this species could focus on managing various ecological habitats by depth, in addition to regulating the fisheries specific to ecomorphs.
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22
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Crispo E, Tunna HR, Hussain N, Rodriguez SS, Pavey SA, Jackson LJ, Rogers SM. The evolution of the major histocompatibility complex in upstream versus downstream river populations of the longnose dace. Ecol Evol 2017; 7:3297-3311. [PMID: 28515867 PMCID: PMC5433983 DOI: 10.1002/ece3.2839] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 01/28/2017] [Indexed: 11/10/2022] Open
Abstract
Populations in upstream versus downstream river locations can be exposed to vastly different environmental and ecological conditions and can thus harbor different genetic resources due to selection and neutral processes. An interesting question is how upstream–downstream directionality in rivers affects the evolution of immune response genes. We used next‐generation amplicon sequencing to identify eight alleles of the major histocompatibility complex (MHC) class II β exon 2 in the cyprinid longnose dace (Rhinichthys cataractae) from three rivers in Alberta, upstream and downstream of municipal and agricultural areas along contaminant gradients. We used these data to test for directional and balancing selection on the MHC. We also genotyped microsatellite loci to examine neutral population processes in this system. We found evidence for balancing selection on the MHC in the form of increased nonsynonymous variation relative to neutral expectations, and selection occurred at more amino acid residues upstream than downstream in two rivers. We found this pattern despite no population structure or isolation by distance, based on microsatellite data, at these sites. Overall, our results suggest that MHC evolution is driven by upstream–downstream directionality in fish inhabiting this system.
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Affiliation(s)
- Erika Crispo
- Department of Biological Sciences University of Calgary Calgary AB Canada
| | - Haley R Tunna
- Department of Biological Sciences University of Calgary Calgary AB Canada
| | - Noreen Hussain
- Department of Biology Pace University New York NY USA.,Present address: Touro College of Pharmacy New York NY USA
| | - Silvia S Rodriguez
- Department of Biology Pace University New York NY USA.,Present address: Developmental Biology Sloan-Kettering Institute New York NY USA
| | - Scott A Pavey
- University of New Brunswick Saint John & Canadian Rivers Institute Saint John NB Canada
| | - Leland J Jackson
- Department of Biological Sciences University of Calgary Calgary AB Canada
| | - Sean M Rogers
- Department of Biological Sciences University of Calgary Calgary AB Canada
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23
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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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24
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Biedrzycka A, Sebastian A, Migalska M, Westerdahl H, Radwan J. Testing genotyping strategies for ultra-deep sequencing of a co-amplifying gene family: MHC class I in a passerine bird. Mol Ecol Resour 2016; 17:642-655. [DOI: 10.1111/1755-0998.12612] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 02/10/2016] [Accepted: 08/23/2016] [Indexed: 12/15/2022]
Affiliation(s)
- Aleksandra Biedrzycka
- Institute of Nature Conservation; Polish Academy of Sciences; Al. Mickiewicza 33 31-120 Kraków Poland
| | - Alvaro Sebastian
- Evolutionary Biology Group; Faculty of Biology; Adam Mickiewicz University; ul. Umultowska 89 61-614 Poznań Poland
| | - Magdalena Migalska
- Evolutionary Biology Group; Faculty of Biology; Adam Mickiewicz University; ul. Umultowska 89 61-614 Poznań Poland
| | - Helena Westerdahl
- Department of Biology; Lund University; Ecology Building, Sölvegatan 37 223 62 Lund Sweden
| | - Jacek Radwan
- Evolutionary Biology Group; Faculty of Biology; Adam Mickiewicz University; ul. Umultowska 89 61-614 Poznań Poland
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25
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Pearson SK, Bradford TM, Ansari TH, Bull CM, Gardner MG. MHC genotyping from next-generation sequencing: detailed methodology for the gidgee skink, Egernia stokesii. T ROY SOC SOUTH AUST 2016. [DOI: 10.1080/03721426.2016.1216735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- S. K. Pearson
- School of Biological Sciences, Flinders University of South Australia, Bedford Park, Australia
| | - T. M. Bradford
- School of Biological Sciences, Flinders University of South Australia, Bedford Park, Australia
| | - T. H. Ansari
- School of Biological Sciences, Flinders University of South Australia, Bedford Park, Australia
| | - C. M. Bull
- School of Biological Sciences, Flinders University of South Australia, Bedford Park, Australia
| | - M. G. Gardner
- School of Biological Sciences, Flinders University of South Australia, Bedford Park, Australia
- Evolutionary Biology Unit, South Australian Museum, Adelaide, Australia
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26
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Egernia stokesii (gidgee skink) MHC I positively selected sites lack concordance with HLA peptide binding regions. Immunogenetics 2016; 69:49-61. [PMID: 27517292 DOI: 10.1007/s00251-016-0947-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 07/25/2016] [Indexed: 10/21/2022]
Abstract
Genes of the major histocompatibility complex (MHC) play an important role in vertebrate disease resistance, kin recognition and mate choice. Mammalian MHC is the most widely characterised of all vertebrates, and attention is often given to the peptide binding regions of the MHC because they are presumed to be under stronger selection than non-peptide binding regions. For vertebrates where the MHC is less well understood, researchers commonly use the amino acid positions of the peptide binding regions of the human leukocyte antigen (HLA) to infer the peptide binding regions within the MHC sequences of their taxon of interest. However, positively selected sites within MHC have been reported to lack correspondence with the HLA in fish, frogs, birds and reptiles including squamates. Despite squamate diversity, the MHC has been characterised in few snakes and lizards. The Egernia group of scincid lizards is appropriate for investigating mechanisms generating MHC variation, as their inclusion will add a new lineage (i.e. Scincidae) to studies of selection on the MHC. We aimed to identify positively selected sites within the MHC of Egernia stokesii and then determine if these sites corresponded with the peptide binding regions of the HLA. Six positively selected sites were identified within E. stokesii MHC I, only two were homologous with the HLA. E. stokesii positively selected sites corresponded more closely to non-lizard than other lizard taxa. The characterisation of the MHC of more intermediate taxa within the squamate order is necessary to understand the evolution of the MHC across all vertebrates.
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27
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Marmesat E, Soriano L, Mazzoni CJ, Sommer S, Godoy JA. PCR Strategies for Complete Allele Calling in Multigene Families Using High-Throughput Sequencing Approaches. PLoS One 2016; 11:e0157402. [PMID: 27294261 PMCID: PMC4905633 DOI: 10.1371/journal.pone.0157402] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/27/2016] [Indexed: 11/19/2022] Open
Abstract
The characterization of multigene families with high copy number variation is often approached through PCR amplification with highly degenerate primers to account for all expected variants flanking the region of interest. Such an approach often introduces PCR biases that result in an unbalanced representation of targets in high-throughput sequencing libraries that eventually results in incomplete detection of the targeted alleles. Here we confirm this result and propose two different amplification strategies to alleviate this problem. The first strategy (called pooled-PCRs) targets different subsets of alleles in multiple independent PCRs using different moderately degenerate primer pairs, whereas the second approach (called pooled-primers) uses a custom-made pool of non-degenerate primers in a single PCR. We compare their performance to the common use of a single PCR with highly degenerate primers using the MHC class I of the Iberian lynx as a model. We found both novel approaches to work similarly well and better than the conventional approach. They significantly scored more alleles per individual (11.33 ± 1.38 and 11.72 ± 0.89 vs 7.94 ± 1.95), yielded more complete allelic profiles (96.28 ± 8.46 and 99.50 ± 2.12 vs 63.76 ± 15.43), and revealed more alleles at a population level (13 vs 12). Finally, we could link each allele's amplification efficiency with the primer-mismatches in its flanking sequences and show that ultra-deep coverage offered by high-throughput technologies does not fully compensate for such biases, especially as real alleles may reach lower coverage than artefacts. Adopting either of the proposed amplification methods provides the opportunity to attain more complete allelic profiles at lower coverages, improving confidence over the downstream analyses and subsequent applications.
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Affiliation(s)
- Elena Marmesat
- Department of Integrative Ecology, Estación Biológica de Doñana (CSIC), Sevilla, Spain
| | - Laura Soriano
- Department of Integrative Ecology, Estación Biológica de Doñana (CSIC), Sevilla, Spain
| | - Camila J. Mazzoni
- Berlin Center for Genomics in Biodiversity Research (BeGenDiv), Berlin, Germany
- Leibniz Institute for Zoo and Wildlife Research (IZW), Berlin, Germany
| | - Simone Sommer
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | - José A. Godoy
- Department of Integrative Ecology, Estación Biológica de Doñana (CSIC), Sevilla, Spain
- * E-mail:
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28
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Gaigher A, Burri R, Gharib WH, Taberlet P, Roulin A, Fumagalli L. Family-assisted inference of the genetic architecture of major histocompatibility complex variation. Mol Ecol Resour 2016; 16:1353-1364. [DOI: 10.1111/1755-0998.12537] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 04/07/2016] [Accepted: 04/18/2016] [Indexed: 12/13/2022]
Affiliation(s)
- A. Gaigher
- Laboratory for Conservation Biology; Department of Ecology and Evolution; University of Lausanne; Biophore Lausanne CH-1015 Switzerland
| | - R. Burri
- Department of Evolutionary Biology; Uppsala University; Norbyvägen 18D SE-752 36 Uppsala Sweden
| | - W. H. Gharib
- Interfaculty Bioinformatics Unit; University of Bern; CH-3012 Bern Switzerland
| | - P. Taberlet
- CNRS; Laboratoire d'Ecologie Alpine (LECA); 38000 Grenoble France
- Laboratoire d'Ecologie Alpine (LECA); University of Grenoble Alpes; 38000 Grenoble France
| | - A. Roulin
- Laboratory for Conservation Biology; Department of Ecology and Evolution; University of Lausanne; Biophore Lausanne CH-1015 Switzerland
| | - L. Fumagalli
- Laboratory for Conservation Biology; Department of Ecology and Evolution; University of Lausanne; Biophore Lausanne CH-1015 Switzerland
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29
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Grogan KE, McGinnis GJ, Sauther ML, Cuozzo FP, Drea CM. Next-generation genotyping of hypervariable loci in many individuals of a non-model species: technical and theoretical implications. BMC Genomics 2016; 17:204. [PMID: 26957424 PMCID: PMC4782575 DOI: 10.1186/s12864-016-2503-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 02/18/2016] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Across species, diversity at the Major Histocompatibility Complex (MHC) is critical to disease resistance and population health; however, use of MHC diversity to quantify the genetic health of populations has been hampered by the extreme variation found in MHC genes. Next generation sequencing (NGS) technology generates sufficient data to genotype even the most diverse species, but workflows for distinguishing artifacts from alleles are still under development. We used NGS to evaluate the MHC diversity of over 300 captive and wild ring-tailed lemurs (Lemur catta: Primates: Mammalia). We modified a published workflow to address errors that arise from deep sequencing individuals and tested for evidence of selection at the most diverse MHC genes. RESULTS In addition to evaluating the accuracy of 454 Titanium and Ion Torrent PGM for genotyping large populations at hypervariable genes, we suggested modifications to improve current methods of allele calling. Using these modifications, we genotyped 302 out of 319 individuals, obtaining an average sequencing depth of over 1000 reads per amplicon. We identified 55 MHC-DRB alleles, 51 of which were previously undescribed, and provide the first sequences of five additional MHC genes: DOA, DOB, DPA, DQA, and DRA. The additional five MHC genes had one or two alleles each with little sequence variation; however, the 55 MHC-DRB alleles showed a high dN/dS ratio and trans-species polymorphism, indicating a history of positive selection. Because each individual possessed 1-7 MHC-DRB alleles, we suggest that ring-tailed lemurs have four, putatively functional, MHC-DRB copies. CONCLUSIONS In the future, accurate genotyping methods for NGS data will be critical to assessing genetic variation in non-model species. We recommend that future NGS studies increase the proportion of replicated samples, both within and across platforms, particularly for hypervariable genes like the MHC. Quantifying MHC diversity within non-model species is the first step to assessing the relationship of genetic diversity at functional loci to individual fitness and population viability. Owing to MHC-DRB diversity and copy number, ring-tailed lemurs may serve as an ideal model for estimating the interaction between genetic diversity, fitness, and environment, especially regarding endangered species.
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Affiliation(s)
- Kathleen E Grogan
- University Program in Ecology, Duke University, Durham, NC, USA.
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA.
- Emory University, Room 2006 O. Wayne Rollins Research Center, 1510 Clifton Rd NE, Atlanta, GA, 30322, USA.
| | | | - Michelle L Sauther
- Department of Anthropology, University of Colorado-Boulder, Boulder, CO, USA
| | - Frank P Cuozzo
- Department of Anthropology, University of North Dakota, Grand Forks, ND, USA
| | - Christine M Drea
- University Program in Ecology, Duke University, Durham, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Department of Biology, Duke University, Durham, USA
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30
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Buczek M, Okarma H, Demiaszkiewicz AW, Radwan J. MHC, parasites and antler development in red deer: no support for the Hamilton & Zuk hypothesis. J Evol Biol 2016; 29:617-32. [PMID: 26687843 DOI: 10.1111/jeb.12811] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 12/08/2015] [Accepted: 12/11/2015] [Indexed: 12/28/2022]
Abstract
The Hamilton-Zuk hypothesis proposes that the genetic benefits of preferences for elaborated secondary sexual traits have their origins in the arms race between hosts and parasites, which maintains genetic variance in parasite resistance. Infection, in turn, can be reflected in the expression of costly sexual ornaments. However, the link between immune genes, infection and the expression of secondary sexual traits has rarely been investigated. Here, we explored whether the presence and identity of functional variants (supertypes) of the highly polymorphic major histocompatibility complex (MHC), which is responsible for the recognition of parasites, predict the load of lung and gut parasites and antler development in the red deer (Cervus elaphus). While we found MHC supertypes to be associated with infection by a number of parasite species, including debilitating lung nematodes, we did not find support for the Hamilton-Zuk hypothesis. On the contrary, we found that lung nematode load was positively associated with antler development. We also found that the supertypes that were associated with resistance to certain parasites at the same time cause susceptibility to others. Such trade-offs may undermine the potential genetic benefits of mate choice for resistant partners.
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Affiliation(s)
- M Buczek
- Institute of Environmental Sciences, Jagiellonian University, Krakow, Poland
| | - H Okarma
- Institute of Nature Conservation, Polish Academy of Sciences, Kraków, Poland
| | | | - J Radwan
- Institute of Environmental Sciences, Jagiellonian University, Krakow, Poland.,Institute of Environmental Biology, Adam Mickiewicz University, Poznań, Poland
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31
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Seifertová M, Jarkovský J, Šimková A. Does the parasite-mediated selection drive the MHC class IIB diversity in wild populations of European chub (Squalius cephalus)? Parasitol Res 2015; 115:1401-15. [PMID: 26693717 DOI: 10.1007/s00436-015-4874-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/07/2015] [Indexed: 11/29/2022]
Abstract
The genes of major histocompatibility complex (MHC) provide an excellent opportunity to study host-parasite relationships because they are expected to evolve in response to parasites and variation in parasite communities. In this study, we investigated the potential role of parasite-mediated selection acting on MHC class IIB (DAB) genes in European chub (Squalius cephalus) natural populations. We found significant differences between populations in metazoan parasites, neutral and adaptive genetic diversities. The analyses based on pairwise data revealed that populations with dissimilar MHC allelic profiles were geographically distant populations with significantly different diversity in microsatellites and a dissimilar composition of parasite communities. The results from the generalized estimating equations method (GEE) on the level of individuals revealed that metazoan parasite load in European chub was influenced by the diversity of DAB alleles as well as by the diversity of neutral genetic markers and host traits reflecting condition and immunocompetence. The multivariate co-inertia analysis showed specific associations between DAB alleles and parasite species. DAB1-like alleles were more involved in associations with ectoparasites, while DAB3-like alleles were positively associated with endoparasites which could suggest potential differences between DAB genes caused by different selection pressure. Our study revealed that parasite-mediated selection is not the only variable affecting MHC diversity in European chub; however, we strongly support the role of neutral processes as the main driver of DAB diversity across populations. In addition, our study contributes to the understanding of the evolution of MHC genes in wild living fish.
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Affiliation(s)
- Mária Seifertová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 61137, Brno, Czech Republic.
| | - Jiří Jarkovský
- Institute of Biostatistics and Analyses, Faculty of Medicine and Faculty of Science, Masaryk University, Kamenice 126/3, 625 00, Brno, Czech Republic
| | - Andrea Šimková
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 61137, Brno, Czech Republic
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32
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Bateson ZW, Whittingham LA, Johnson JA, Dunn PO. Contrasting patterns of selection and drift between two categories of immune genes in prairie-chickens. Mol Ecol 2015; 24:6095-106. [PMID: 26547898 DOI: 10.1111/mec.13459] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 10/31/2015] [Accepted: 11/03/2015] [Indexed: 12/22/2022]
Abstract
Immune-receptor genes of the adaptive immune system, such as the major histocompatibility complex (MHC), are involved in recognizing specific pathogens and are known to have high rates of adaptive evolution, presumably as a consequence of rapid co-evolution between hosts and pathogens. In contrast, many 'mediating' genes of the immune system do not interact directly with specific pathogens and are involved in signalling (e.g. cytokines) or controlling immune cell growth. As a consequence, we might expect stronger selection at immune-receptor than mediating genes, but these two types of genes have not been compared directly in wild populations. Here, we tested the hypothesis that selection differs between MHC (class I and II) and mediating genes by comparing levels of population differentiation across the range of greater prairie-chickens (Tympanuchus cupido). As predicted, there was stronger population differentiation and isolation by distance at immune receptor (MHC) than at either mediating genes or neutral microsatellites, suggesting a stronger role of local adaptation at the MHC. In contrast, mediating genes displayed weaker differentiation between populations than neutral microsatellites, consistent with selection favouring similar alleles across populations for mediating genes. In addition to selection, drift also had a stronger effect on immune receptor (MHC) than mediating genes as indicated by the stronger decline of MHC variation in relation to population size. This is the first study in the wild to show that the effects of selection and drift on immune genes vary across populations depending on their functional role.
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Affiliation(s)
- Zachary W Bateson
- Behavioral and Molecular Ecology Group, Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Linda A Whittingham
- Behavioral and Molecular Ecology Group, Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Jeff A Johnson
- Department of Biological Sciences, Institute of Applied Sciences, University of North Texas, Denton, TX, USA
| | - Peter O Dunn
- Behavioral and Molecular Ecology Group, Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
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33
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Lack of Spatial Immunogenetic Structure among Wolverine (Gulo gulo) Populations Suggestive of Broad Scale Balancing Selection. PLoS One 2015; 10:e0140170. [PMID: 26448462 PMCID: PMC4598017 DOI: 10.1371/journal.pone.0140170] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/22/2015] [Indexed: 11/19/2022] Open
Abstract
Elucidating the adaptive genetic potential of wildlife populations to environmental selective pressures is fundamental for species conservation. Genes of the major histocompatibility complex (MHC) are highly polymorphic, and play a key role in the adaptive immune response against pathogens. MHC polymorphism has been linked to balancing selection or heterogeneous selection promoting local adaptation. However, spatial patterns of MHC polymorphism are also influenced by gene flow and drift. Wolverines are highly vagile, inhabiting varied ecoregions that include boreal forest, taiga, tundra, and high alpine ecosystems. Here, we investigated the immunogenetic variation of wolverines in Canada as a surrogate for identifying local adaptation by contrasting the genetic structure at MHC relative to the structure at 11 neutral microsatellites to account for gene flow and drift. Evidence of historical positive selection was detected at MHC using maximum likelihood codon-based methods. Bayesian and multivariate cluster analyses revealed weaker population genetic differentiation at MHC relative to the increasing microsatellite genetic structure towards the eastern wolverine distribution. Mantel correlations of MHC against geographical distances showed no pattern of isolation by distance (IBD: r = -0.03, p = 0.9), whereas for microsatellites we found a relatively strong and significant IBD (r = 0.54, p = 0.01). Moreover, we found a significant correlation between microsatellite allelic richness and the mean number of MHC alleles, but we did not observe low MHC diversity in small populations. Overall these results suggest that MHC polymorphism has been influenced primarily by balancing selection and to a lesser extent by neutral processes such as genetic drift, with no clear evidence for local adaptation. This study contributes to our understanding of how vulnerable populations of wolverines may respond to selective pressures across their range.
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34
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Sebastian A, Herdegen M, Migalska M, Radwan J. amplisas: a web server for multilocus genotyping using next-generation amplicon sequencing data. Mol Ecol Resour 2015; 16:498-510. [DOI: 10.1111/1755-0998.12453] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Revised: 07/16/2015] [Accepted: 08/04/2015] [Indexed: 12/30/2022]
Affiliation(s)
- Alvaro Sebastian
- Evolutionary Biology Group; Faculty of Biology; Adam Mickiewicz University; ul. Umultowska 89 61-614 Poznan Poland
| | - Magdalena Herdegen
- Evolutionary Biology Group; Faculty of Biology; Adam Mickiewicz University; ul. Umultowska 89 61-614 Poznan Poland
| | - Magdalena Migalska
- Evolutionary Biology Group; Faculty of Biology; Adam Mickiewicz University; ul. Umultowska 89 61-614 Poznan Poland
| | - Jacek Radwan
- Evolutionary Biology Group; Faculty of Biology; Adam Mickiewicz University; ul. Umultowska 89 61-614 Poznan Poland
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35
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Fijarczyk A, Babik W. Detecting balancing selection in genomes: limits and prospects. Mol Ecol 2015; 24:3529-45. [DOI: 10.1111/mec.13226] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/27/2015] [Accepted: 04/30/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Anna Fijarczyk
- Institute of Environmental Sciences; Jagiellonian University; Gronostajowa 7 30-387 Kraków Poland
| | - Wiesław Babik
- Institute of Environmental Sciences; Jagiellonian University; Gronostajowa 7 30-387 Kraków Poland
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36
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Gasparini C, Congiu L, Pilastro A. Major histocompatibility complex similarity and sexual selection: different does not always mean attractive. Mol Ecol 2015; 24:4286-95. [PMID: 25940673 DOI: 10.1111/mec.13222] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/03/2015] [Accepted: 04/08/2015] [Indexed: 12/16/2022]
Abstract
Females that mate multiply have the possibility to exert postcopulatory choice and select more compatible sperm to fertilize eggs. Prior work suggests that dissimilarity in major histocompatibility complex (MHC) plays an important role in determining genetic compatibility between partners. Favouring a partner with dissimilar MHC alleles would result in offspring with high MHC diversity and therefore with enhanced survival thanks to increased resistance to pathogens and parasites. The high variability of MHC genes may further allow discrimination against the sperm from related males, reducing offspring homozygosity and inbreeding risk. Despite the large body of work conducted at precopulatory level, the role of MHC similarity between partners at postcopulatory level has been rarely investigated. We used an internal fertilizing fish with high level of multiple matings (Poecilia reticulata) to study whether MHC similarity plays a role in determining the outcome of fertilization when sperm from two males compete for the same set of eggs. We also controlled for genomewide similarity by determining similarity at 10 microsatellite loci. Contrary to prediction, we found that the more MHC-similar male sired more offspring while similarity at the microsatellite loci did not predict the outcome of sperm competition. Our results suggest that MHC discrimination may be involved in avoidance of hybridization or outbreeding rather than inbreeding avoidance. This, coupled with similar findings in salmon, suggests that the preference for MHC-dissimilar mates is far from being unanimous and that pre- and postcopulatory episodes of sexual selection can indeed act in opposite directions.
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Affiliation(s)
- Clelia Gasparini
- Department of Biology, University of Padova, Padova, 35100, Italy.,Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, WA, 6009, Australia
| | - Leonardo Congiu
- Department of Biology, University of Padova, Padova, 35100, Italy
| | - Andrea Pilastro
- Department of Biology, University of Padova, Padova, 35100, Italy
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37
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Ferrandiz-Rovira M, Bigot T, Allainé D, Callait-Cardinal MP, Cohas A. Large-scale genotyping of highly polymorphic loci by next-generation sequencing: how to overcome the challenges to reliably genotype individuals? Heredity (Edinb) 2015; 114:485-93. [PMID: 25757407 DOI: 10.1038/hdy.2015.13] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 01/19/2015] [Accepted: 01/23/2015] [Indexed: 11/10/2022] Open
Abstract
Studying the different roles of adaptive genes is still a challenge in evolutionary ecology and requires reliable genotyping of large numbers of individuals. Next-generation sequencing (NGS) techniques enable such large-scale sequencing, but stringent data processing is required. Here, we develop an easy to use methodology to process amplicon-based NGS data and we apply this methodology to reliably genotype four major histocompatibility complex (MHC) loci belonging to MHC class I and II of Alpine marmots (Marmota marmota). Our post-processing methodology allowed us to increase the number of retained reads. The quality of genotype assignment was further assessed using three independent validation procedures. A total of 3069 high-quality MHC genotypes were obtained at four MHC loci for 863 Alpine marmots with a genotype assignment error rate estimated as 0.21%. The proposed methodology could be applied to any genetic system and any organism, except when extensive copy-number variation occurs (that is, genes with a variable number of copies in the genotype of an individual). Our results highlight the potential of amplicon-based NGS techniques combined with adequate post-processing to obtain the large-scale highly reliable genotypes needed to understand the evolution of highly polymorphic functional genes.
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Affiliation(s)
- M Ferrandiz-Rovira
- 1] Laboratoire Biométrie et Biologie Evolutive, Université de Lyon, CNRS, UMR5558, Université Lyon 1, F-69622, Villeurbanne, F-69000 Lyon, France [2] Université Lyon, VetAgro Sup Campus Vet, Marcy-L'Étoile, France
| | - T Bigot
- Laboratoire Biométrie et Biologie Evolutive, Université de Lyon, CNRS, UMR5558, Université Lyon 1, F-69622, Villeurbanne, F-69000 Lyon, France
| | - D Allainé
- Laboratoire Biométrie et Biologie Evolutive, Université de Lyon, CNRS, UMR5558, Université Lyon 1, F-69622, Villeurbanne, F-69000 Lyon, France
| | - M-P Callait-Cardinal
- 1] Laboratoire Biométrie et Biologie Evolutive, Université de Lyon, CNRS, UMR5558, Université Lyon 1, F-69622, Villeurbanne, F-69000 Lyon, France [2] Université Lyon, VetAgro Sup Campus Vet, Marcy-L'Étoile, France
| | - A Cohas
- Laboratoire Biométrie et Biologie Evolutive, Université de Lyon, CNRS, UMR5558, Université Lyon 1, F-69622, Villeurbanne, F-69000 Lyon, France
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