1
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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: 0] [Impact Index Per Article: 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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2
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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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3
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Holmes IA, Grundler MC. Phylogenetically under-dispersed gut microbiomes are not correlated with host genomic heterozygosity in a genetically diverse reptile community. Mol Ecol 2023; 32:258-274. [PMID: 36221927 PMCID: PMC9797449 DOI: 10.1111/mec.16733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/09/2022] [Accepted: 09/15/2022] [Indexed: 12/31/2022]
Abstract
While key elements of fitness in vertebrate animals are impacted by their microbiomes, the host genetic characteristics that factor into microbiome composition are not fully understood. Here, we correlate host genomic heterozygosity and gut microbiome phylogenetic diversity across a community of reptiles in southwestern New Mexico to test hypotheses about the behaviour of host genes that drive microbiome assembly. We find that microbiome communities are phylogenetically under-dispersed relative to random expectations, and that host heterozygosity is not correlated with microbiome diversity. Our analyses reinforce results from functional genomic work that identify conserved host immune and nonimmune genes as key players in microbiome assembly, rather than gene families that rely on heterozygosity for their function.
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Affiliation(s)
- Iris A. Holmes
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109 USA
- Cornell Institute of Host Microbe Interactions and Disease and Department of Microbiology, Cornell University, Ithaca, NY 14853 USA
| | - Michael C. Grundler
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109 USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095 USA
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4
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Chen RS, Soulsbury CD, Lebigre C, Ludwig G, van Oers K, Hoffman JI. Effects of hunting on genetic diversity, inbreeding and dispersal in Finnish black grouse (
Lyrurus tetrix
). Evol Appl 2022; 16:625-637. [PMID: 36969146 PMCID: PMC10033861 DOI: 10.1111/eva.13521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 12/06/2022] [Indexed: 12/28/2022] Open
Abstract
Intensive hunting activities such as commercial fishing and trophy hunting can have profound influences on natural populations. However, less intensive recreational hunting can also have subtle effects on animal behaviour, habitat use and movement, with implications for population persistence. Lekking species such as the black grouse (Lyrurus tetrix) may be especially prone to hunting as leks are temporally and spatially predictable, making them easy targets. Furthermore, inbreeding in black grouse is mainly avoided through female-biased dispersal, so any disruptions to dispersal caused by hunting could lead to changes in gene flow, increasing the risk of inbreeding. We therefore investigated the impact of hunting on genetic diversity, inbreeding and dispersal on a metapopulation of black grouse in Central Finland. We genotyped 1065 adult males and 813 adult females from twelve lekking sites (six hunted, six unhunted) and 200 unrelated chicks from seven sites (two hunted, five unhunted) at up to thirteen microsatellite loci. Our initial confirmatory analysis of sex-specific fine-scale population structure revealed little genetic structure in the metapopulation. Levels of inbreeding did not differ significantly between hunted and unhunted sites in neither adults nor chicks. However, immigration rates into hunted sites were significantly higher among adults compared to immigration into unhunted sites. We conclude that the influx of migrants into hunted sites may compensate for the loss of harvested individuals, thereby increasing gene flow and mitigating inbreeding. Given the absence of any obvious barriers to gene flow in Central Finland, a spatially heterogeneous matrix of hunted and unhunted regions may be crucial to ensure sustainable harvests into the future.
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Affiliation(s)
- Rebecca S. Chen
- Department of Animal Behaviour University of Bielefeld Bielefeld Germany
| | - Carl D. Soulsbury
- School of Life and Environmental Sciences, Joseph Banks Laboratories University of Lincoln Lincoln UK
| | - Christophe Lebigre
- UMR DECOD (Ecosystem Dynamics and Sustainability), IFREMER, INRAE Institut Agro Plouzané France
| | - Gilbert Ludwig
- Institute of Bioeconomy JAMK University of Applied Sciences Tarvaala Finland
| | - Kees van Oers
- Department of Animal Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Wageningen The Netherlands
| | - Joseph I. Hoffman
- Department of Animal Behaviour University of Bielefeld Bielefeld Germany
- British Antarctic Survey Cambridge UK
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5
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Selection and demography drive range-wide patterns of MHC-DRB variation in mule deer. BMC Ecol Evol 2022; 22:42. [PMID: 35387584 PMCID: PMC8988406 DOI: 10.1186/s12862-022-01998-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 03/14/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Standing genetic variation is important especially in immune response-related genes because of threats to wild populations like the emergence of novel pathogens. Genetic variation at the major histocompatibility complex (MHC), which is crucial in activating the adaptive immune response, is influenced by both natural selection and historical population demography, and their relative roles can be difficult to disentangle. To provide insight into the influences of natural selection and demography on MHC evolution in large populations, we analyzed geographic patterns of variation at the MHC class II DRB exon 2 locus in mule deer (Odocoileus hemionus) using sequence data collected across their entire broad range. RESULTS We identified 31 new MHC-DRB alleles which were phylogenetically similar to other cervid MHC alleles, and one allele that was shared with white-tailed deer (Odocoileus virginianus). We found evidence for selection on the MHC including high dN/dS ratios, positive neutrality tests, deviations from Hardy-Weinberg Equilibrium (HWE) and a stronger pattern of isolation-by-distance (IBD) than expected under neutrality. Historical demography also shaped variation at the MHC, as indicated by similar spatial patterns of variation between MHC and microsatellite loci and a lack of association between genetic variation at either locus type and environmental variables. CONCLUSIONS Our results show that both natural selection and historical demography are important drivers in the evolution of the MHC in mule deer and work together to shape functional variation and the evolution of the adaptive immune response in large, well-connected populations.
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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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7
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Stefanović M, Ćirović D, Bogdanović N, Knauer F, Heltai M, Szabó L, Lanszki J, Zhelev CD, Schaschl H, Suchentrunk F. Positive selection on the MHC class II DLA-DQA1 gene in golden jackals (Canis aureus) from their recent expansion range in Europe and its effect on their body mass index. BMC Ecol Evol 2021; 21:122. [PMID: 34134625 PMCID: PMC8207625 DOI: 10.1186/s12862-021-01856-z] [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: 11/18/2020] [Accepted: 06/10/2021] [Indexed: 11/17/2022] Open
Abstract
Background In Europe, golden jackals (Canis aureus) have been expanding their range out of the southern and southeastern Balkans towards central Europe continually since the 1960s. Here, we investigated the level of functional diversity at the MHC class II DLA-DQA1 exon 2 in golden jackal populations from Bulgaria, Serbia, and Hungary. Specifically, we tested for positive selection on and geographic variation at that locus due to adaptation to supposedly regionally varying pathogenic landscapes. To test for potential fitness effects of different protein variants on individual body condition, we used linear modeling of individual body mass indexes (bmi) and accounted for possible age, sex, geographical, and climatic effects. The latter approach was performed, however, only on Serbian individuals with appropriate data. Results Only three different DLA-DQA1 alleles were detected, all coding for different amino-acid sequences. The neutrality tests revealed no significant but positive values; there was no signal of spatial structuring and no deviation from the Hardy–Weinberg equilibrium across the studied range of expansion. However, we found a signal of trans-species polymorphism and significant test results for positive selection on three codons. Our information-theory based linear modeling results indicated an effect of ambient temperature on the occurrence of individual DLA-DQA1 genotypes in individuals from across the studied expansion range, independent from geographical position. Our linear modeling results of individual bmi values indicated that yearlings homozygous for DLA-DQA1*03001 reached values typical for adults contrary to yearlings carrying other genotypes (protein combinations). This suggested better growth rates and thus a possible fitness advantage of yearlings homozygous for DLA-DQA1*03001. Conclusions Our results indicate a demographic (stochastic) signal of reduced DLA-DQA1 exon 2 variation, in line with the documented historical demographic bottleneck. At the same time, however, allelic variation was also affected by positive selection and adaptation to varying ambient temperature, supposedly reflecting geographic variation in the pathogenic landscape. Moreover, an allele effect on body mass index values of yearlings suggested differential fitness associated with growth rates. Overall, a combination of a stochastic effect and positive selection has shaped and is still shaping the variation at the studied MHC locus. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01856-z.
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Affiliation(s)
- Milomir Stefanović
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 2, 21000, Novi Sad, Serbia.,Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Savoyenstrasse 1, 1160, Vienna, Austria
| | - Duško Ćirović
- Faculty of Biology, University of Belgrade, Studentski trg 16, 11000, Belgrade, Serbia
| | - Neda Bogdanović
- Faculty of Biology, University of Belgrade, Studentski trg 16, 11000, Belgrade, Serbia
| | - Felix Knauer
- Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Savoyenstrasse 1, 1160, Vienna, Austria
| | - Miklós Heltai
- Institute for Wildlife Conservation, Szent István University, Páter Károly utca 1, Gödöllő, 2100, Hungary
| | - László Szabó
- Institute for Wildlife Conservation, Szent István University, Páter Károly utca 1, Gödöllő, 2100, Hungary
| | - József Lanszki
- Ecological Research Group, University of Kaposvár, PO Box 16, 7401, Kaposvár, Hungary
| | | | - Helmut Schaschl
- Department of Evolutionary Anthropology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.
| | - Franz Suchentrunk
- Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Savoyenstrasse 1, 1160, Vienna, Austria
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8
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Trujillo AL, Hoffman EA, Becker CG, Savage AE. Spatiotemporal adaptive evolution of an MHC immune gene in a frog-fungus disease system. Heredity (Edinb) 2021; 126:640-655. [PMID: 33510466 PMCID: PMC8115231 DOI: 10.1038/s41437-020-00402-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 12/29/2020] [Accepted: 12/31/2020] [Indexed: 01/30/2023] Open
Abstract
Genetic diversity of major histocompatibility complex (MHC) genes is linked to reduced pathogen susceptibility in amphibians, but few studies also examine broad spatial and temporal patterns of MHC and neutral genetic diversity. Here, we characterized range-wide MHC diversity in the Northern leopard frog, Rana pipiens, a species found throughout North America that is experiencing disease-related declines. We used previously sequenced neutral markers (mitochondrial DNA and microsatellites), sequenced an expressed MHC class IIß gene fragment, and measured infection prevalence and intensity of the global fungal pathogen Batrachochytrium dendrobatidis (Bd) across 14 populations. Four populations were sampled across two decades, enabling temporal comparisons of selection and demography. We recovered 37 unique MHC alleles, including 17 that were shared across populations. Phylogenetic and population genetic patterns between MHC and neutral markers were incongruent, and five MHC codon positions associated with peptide binding were under positive selection. MHC heterozygosity, but not neutral marker heterozygosity, was a significant factor explaining spatial patterns of Bd prevalence, whereas only environmental variables predicted Bd intensity. MHC allelic richness (AR) decreased significantly over time but microsatellite-based AR did not, highlighting a loss of functional immunogenetic diversity that may be associated with Bd selective pressures. MHC supertype 4 was significantly associated with an elevated risk of Bd infection, whereas one supertype 2 allele was associated with a nearly significant reduced risk of Bd. Taken together, these results provide evidence that positive selection contributes to MHC class IIß evolution in R. pipiens and suggest that functional MHC differences across populations may contribute to disease adaptation.
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Affiliation(s)
- Alexa L. Trujillo
- grid.170430.10000 0001 2159 2859Department of Biology, University of Central Florida, Orlando, FL USA
| | - Eric A. Hoffman
- grid.170430.10000 0001 2159 2859Department of Biology, University of Central Florida, Orlando, FL USA
| | - C. Guilherme Becker
- grid.411015.00000 0001 0727 7545Department of Biological Sciences, University of Alabama, Tuscaloosa, AL USA
| | - Anna E. Savage
- grid.170430.10000 0001 2159 2859Department of Biology, University of Central Florida, Orlando, FL USA
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Perrin A, Khimoun A, Faivre B, Ollivier A, de Pracontal N, Théron F, Loubon M, Leblond G, Duron O, Garnier S. Habitat fragmentation differentially shapes neutral and immune gene variation in a tropical bird species. Heredity (Edinb) 2021; 126:148-162. [PMID: 32934360 PMCID: PMC7853120 DOI: 10.1038/s41437-020-00366-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/30/2020] [Accepted: 08/30/2020] [Indexed: 01/11/2023] Open
Abstract
Habitat fragmentation is a major cause of biodiversity loss, responsible for an alteration of intraspecific patterns of neutral genetic diversity and structure. Although neutral genetic variation can be informative for demographic inferences, it may be a poor predictor of adaptive genetic diversity and thus of the consequences of habitat fragmentation on selective evolutionary processes. In this context, we contrasted patterns of genetic diversity and structure of neutral loci (microsatellites) and immune genes (i.e., toll-like receptors) in an understorey bird species, the wedge-billed woodcreeper Glyphorynchus spirurus. The objectives were (1) to investigate forest fragmentation effects on population genetic diversity, (2) to disentangle the relative role of demography (genetic drift and migration) and selection, and (3) to assess whether immunogenetic patterns could be associated with variation of ectoparasite (i.e., ticks) pressures. Our results revealed an erosion of neutral genetic diversity and a substantial genetic differentiation among fragmented populations, resulting from a decrease in landscape connectivity and leading to the divergence of distinct genetic pools at a small spatial scale. Patterns of genetic diversity observed for TLR4 and TLR5 were concordant with neutral genetic patterns, whereas those observed for TLR3 and TLR21 were discordant. This result underlines that the dominant evolutionary force shaping immunogenetic diversity (genetic drift vs. selection) may be different depending on loci considered. Finally, tick prevalence was higher in fragmented environments. We discussed the hypothesis that pathogen selective pressures may contribute to maintain adaptive genetic diversity despite the negative demographic effect of habitat fragmentation on neutral genetic diversity.
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Affiliation(s)
- Antoine Perrin
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France.
| | - Aurélie Khimoun
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France
| | - Bruno Faivre
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France
| | - Anthony Ollivier
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France
| | - Nyls de Pracontal
- Groupe d'Etude et de Protection des Oiseaux en Guyane, 431 route d'Attila Cabassou, 97354, Rémire-Montjoly, France
| | - Franck Théron
- Groupe d'Etude et de Protection des Oiseaux en Guyane, 431 route d'Attila Cabassou, 97354, Rémire-Montjoly, France
| | - Maxime Loubon
- Groupe d'Etude et de Protection des Oiseaux en Guyane, 431 route d'Attila Cabassou, 97354, Rémire-Montjoly, France
| | - Gilles Leblond
- SARL BIOS, Route de Davidon, Duzer, 97115, Sainte-Rose, France
| | - Olivier Duron
- Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), Centre National de la Recherche Scientifique (CNRS), Institut pour la Recherche et le Développement (IRD), Université de Montpellier (UM), Montpellier, France
| | - Stéphane Garnier
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France
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10
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Yi X, Donner DM, Marquardt PE, Palmer JM, Jusino MA, Frair J, Lindner DL, Latch EK. Major histocompatibility complex variation is similar in little brown bats before and after white-nose syndrome outbreak. Ecol Evol 2020; 10:10031-10043. [PMID: 33005361 PMCID: PMC7520216 DOI: 10.1002/ece3.6662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 07/18/2020] [Accepted: 07/19/2020] [Indexed: 12/28/2022] Open
Abstract
White-nose syndrome (WNS), caused by the fungal pathogen Pseudogymnoascus destructans (Pd), has driven alarming declines in North American hibernating bats, such as little brown bat (Myotis lucifugus). During hibernation, infected little brown bats are able to initiate anti-Pd immune responses, indicating pathogen-mediated selection on the major histocompatibility complex (MHC) genes. However, such immune responses may not be protective as they interrupt torpor, elevate energy costs, and potentially lead to higher mortality rates. To assess whether WNS drives selection on MHC genes, we compared the MHC DRB gene in little brown bats pre- (Wisconsin) and post- (Michigan, New York, Vermont, and Pennsylvania) WNS (detection spanning 2014-2015). We genotyped 131 individuals and found 45 nucleotide alleles (27 amino acid alleles) indicating a maximum of 3 loci (1-5 alleles per individual). We observed high allelic admixture and a lack of genetic differentiation both among sampling sites and between pre- and post-WNS populations, indicating no signal of selection on MHC genes. However, post-WNS populations exhibited decreased allelic richness, reflecting effects from bottleneck and drift following rapid population declines. We propose that mechanisms other than adaptive immunity are more likely driving current persistence of little brown bats in affected regions.
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Affiliation(s)
- Xueling Yi
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukeeWIUSA
| | - Deahn M. Donner
- Northern Research StationUSDA Forest ServiceRhinelanderWIUSA
| | | | | | - Michelle A. Jusino
- Northern Research StationUSDA Forest ServiceMadisonWIUSA
- Department of Plant PathologyUniversity of FloridaGainesvilleFLUSA
| | - Jacqueline Frair
- Roosevelt Wild Life StationSUNY College of Environmental Science and ForestrySyracuseNYUSA
| | | | - Emily K. Latch
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukeeWIUSA
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11
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Meléndez-Rosa J, Bi K, Lacey EA. Mating system is correlated with immunogenetic diversity in sympatric species of Peromyscine mice. PLoS One 2020; 15:e0236084. [PMID: 32701975 PMCID: PMC7377423 DOI: 10.1371/journal.pone.0236084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 06/29/2020] [Indexed: 11/18/2022] Open
Abstract
The number of reproductive partners per individual varies markedly across animal mating systems. This variation may be an important determinant of patterns of immunogenetic diversity, particularly at Major Histocompatibility Complex (MHC) Class I and II loci. To compare immunogenetic variation in taxa with markedly different mating systems, we used RNAseq-generated data to quantify genotypic diversity in three species of Peromyscine rodents: the monogamous California mouse (Peromyscus californicus) and the polygynandrous deer mouse (P. maniculatus) and brush mouse (P. boylii). By sampling populations of these species from multiple localities in California, we were able to conduct replicated analyses of the relationship between mating system and immunogenetic variation. Across the four localities sampled, diversity at MHC Class I and II genes was consistently higher in the two polygynandrous species. We found no evidence that sampling location (i.e., variation in habitat conditions) contributed to observed differences in MHC variation among populations or species. Collectively, our data indicate that immunogenetic variation in Peromyscine mice is associated with reproductive behavior, rather than geographic locality or habitat type. The consistently greater variability detected in the polygynandrous species examined suggests that balancing selection imposed by behaviorally-mediated pathogen exposure is important in maintaining variation at MHC genes in these animals.
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Affiliation(s)
- Jesyka Meléndez-Rosa
- Department of Integrative Biology, University of California, Berkeley, California, United States of America
- Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
| | - Ke Bi
- Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
- Computational Genomics Resource Laboratory, University of California, Berkeley, California, United States of America
| | - Eileen A. Lacey
- Department of Integrative Biology, University of California, Berkeley, California, United States of America
- Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
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12
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Biedrzycka A, Konopiński M, Hoffman E, Trujillo A, Zalewski A. Comparing raccoon major histocompatibility complex diversity in native and introduced ranges: Evidence for the importance of functional immune diversity for adaptation and survival in novel environments. Evol Appl 2020; 13:752-767. [PMID: 32211065 PMCID: PMC7086054 DOI: 10.1111/eva.12898] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 09/27/2019] [Accepted: 10/16/2019] [Indexed: 12/21/2022] Open
Abstract
The adaptive potential of invasive species is related to the genetic diversity of the invader, which is influenced by genetic drift and natural selection. Typically, the genetic diversity of invaders is studied with neutral genetic markers; however, the expectation of reduced diversity has not been consistently supported by empirical studies. Here, we describe and interpret genetic diversity at both neutral microsatellite loci and the immune-related MHC-DRB locus of native and invasive populations of raccoon to better understand of how drift and selection impact patterns of genetic diversity during the invasion process. We found that despite the loss of many MHC (major histocompatibility complex) alleles in comparison with native populations, functional MHC supertypes are preserved in the invasive region. In the native raccoon population, the number of supertypes within individuals was higher than expected under a neutral model. The high level of individual functional divergence may facilitate the adaptation to local conditions in the invasive range. In the invasive populations, we also detected increased population structure at microsatellites compared to the MHC locus, further suggesting that balancing selection is acting on adaptively important regions of the raccoon genome. Finally, we found that alleles known to exhibit resistance to rabies in the native range, Prlo-DRB*4, Prlo-DRB*16 and Prlo-DRB*102, were the most common alleles in the European populations, suggesting directional selection is acting on this locus. Our research shows empirical support for the importance of functional immune diversity for adaptation and survival in novel environments.
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Affiliation(s)
| | - Maciej Konopiński
- Institute of Nature ConservationPolish Academy of SciencesKrakówPoland
| | - Eric Hoffman
- Department of BiologyUniversity of Central FloridaOrlandoFLUSA
| | - Alexa Trujillo
- Department of BiologyUniversity of Central FloridaOrlandoFLUSA
| | - Andrzej Zalewski
- Mammal Research InstitutePolish Academy of SciencesBiałowieżaPoland
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13
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O'Connor EA, Hasselquist D, Nilsson JÅ, Westerdahl H, Cornwallis CK. Wetter climates select for higher immune gene diversity in resident, but not migratory, songbirds. Proc Biol Sci 2020; 287:20192675. [PMID: 31992169 PMCID: PMC7015325 DOI: 10.1098/rspb.2019.2675] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Pathogen communities can vary substantially between geographical regions due to different environmental conditions. However, little is known about how host immune systems respond to environmental variation across macro-ecological and evolutionary scales. Here, we select 37 species of songbird that inhabit diverse environments, including African and Palaearctic residents and Afro-Palaearctic migrants, to address how climate and habitat have influenced the evolution of key immune genes, the major histocompatibility complex class I (MHC-I). Resident species living in wetter regions, especially in Africa, had higher MHC-I diversity than species living in drier regions, irrespective of the habitats they occupy. By contrast, no relationship was found between MHC-I diversity and precipitation in migrants. Our results suggest that the immune system of birds has evolved greater pathogen recognition in wetter tropical regions. Furthermore, evolving transcontinental migration appears to have enabled species to escape wet, pathogen-rich areas at key periods of the year, relaxing selection for diversity in immune genes and potentially reducing immune system costs.
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14
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Rocha RG, Magalhães V, López-Bao JV, van der Loo W, Llaneza L, Alvares F, Esteves PJ, Godinho R. Alternated selection mechanisms maintain adaptive diversity in different demographic scenarios of a large carnivore. BMC Evol Biol 2019; 19:90. [PMID: 30975084 PMCID: PMC6460805 DOI: 10.1186/s12862-019-1420-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 04/04/2019] [Indexed: 01/26/2023] Open
Abstract
Background Different population trajectories are expected to impact the signature of neutral and adaptive processes at multiple levels, challenging the assessment of the relative roles of different microevolutionary forces. Here, we integrate adaptive and neutral variability patterns to disentangle how adaptive diversity is driven under different demographic scenarios within the Iberian wolf (Canis lupus) range. We studied the persistent, the expanding and a small, isolated group within the Iberian wolf population, using 3 MHC class II genes (DRB1, DQA1, and DQB1), which diversity was compared with 39 microsatellite loci. Results Both the persistent and the expanding groups show evidence of balancing selection, revealed by a significant departure from neutrality at MHC loci, significant higher observed and expected heterozygosity and lower differentiation at MHC than at neutral loci, and signs of positive selection. However, despite exhibiting a significantly higher genetic diversity than the isolated group, the persistent group did not show significant excess of MHC heterozygotes. The expanding group, while showing a similar level of genetic diversity than the persistent group, displays by contrast a significant excess of MHC heterozygotes, which is compatible with the heterozygote advantage mechanism. Results are not clear regarding the role of drift and selection in the isolated group due to the small size of this population. Although diversity indices of MHC loci correspond to neutral expectations in the isolated group, accelerated MHC divergence, revealed by a higher differentiation at MHC than neutral loci, may indicate diversifying selection. Conclusion Different selective pressures were observed in the three different demographic scenarios, which are possibly driven by different selection mechanisms to maintain adaptive diversity. Electronic supplementary material The online version of this article (10.1186/s12862-019-1420-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rita G Rocha
- CIBIO/InBio - Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Vanessa Magalhães
- CIBIO/InBio - Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus de Vairão, 4485-661, Vairão, Portugal
| | - José V López-Bao
- Research Unit of Biodiversity (UO/CSIC/PA), University of Oviedo, 33600, Mieres, Spain
| | - Wessel van der Loo
- CIBIO/InBio - Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Luis Llaneza
- A.RE.NA, S.L. Asesores en Recursos Naturales S.L., 27003, Lugo, Spain
| | - Francisco Alvares
- CIBIO/InBio - Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Pedro J Esteves
- CIBIO/InBio - Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus de Vairão, 4485-661, Vairão, Portugal.,Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169-007, Porto, Portugal
| | - Raquel Godinho
- CIBIO/InBio - Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus de Vairão, 4485-661, Vairão, Portugal. .,Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169-007, Porto, Portugal.
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15
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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: 9] [Impact Index Per Article: 1.8] [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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16
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Montero BK, Refaly E, Ramanamanjato J, Randriatafika F, Rakotondranary SJ, Wilhelm K, Ganzhorn JU, Sommer S. Challenges of next-generation sequencing in conservation management: Insights from long-term monitoring of corridor effects on the genetic diversity of mouse lemurs in a fragmented landscape. Evol Appl 2019; 12:425-442. [PMID: 30828365 PMCID: PMC6383737 DOI: 10.1111/eva.12723] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 09/24/2018] [Accepted: 09/30/2018] [Indexed: 01/30/2023] Open
Abstract
Long-term genetic monitoring of populations is essential for efforts aimed at preserving genetic diversity of endangered species. Here, we employ a framework of long-term genetic monitoring to evaluate the effects of fragmentation and the effectiveness of the establishment of corridors in restoring population connectivity and genetic diversity of mouse lemurs Microcebus ganzhorni. To this end, we supplement estimates of neutral genetic diversity with the assessment of adaptive genetic variability of the major histocompatibility complex (MHC). In addition, we address the challenges of long-term genetic monitoring of functional diversity by comparing the genotyping performance and estimates of MHC variability generated by single-stranded conformation polymorphism (SSCP)/Sanger sequencing with those obtained by high-throughput sequencing (next-generation sequencing [NGS], Illumina), an issue that is particularly relevant when previous work serves as a baseline for planning management strategies that aim to ensure the viability of a population. We report that SSCP greatly underestimates individual diversity and that discrepancies in estimates of MHC diversity attributable to the comparisons of traditional and NGS genotyping techniques can influence the conclusions drawn from conservation management scenarios. Evidence of migration among fragments in Mandena suggests that mouse lemurs are robust to the process of fragmentation and that the effect of corridors is masked by ongoing gene flow. Nonetheless, results based on a larger number of shared private alleles at neutral loci between fragment pairs found after the establishment of corridors in Mandena suggest that gene flow is augmented as a result of enhanced connectivity. Our data point out that despite low effective population size, M. ganzhorni maintains high individual heterozygosity at neutral loci and at MHC II DRB gene and that selection plays a predominant role in maintaining MHC diversity. These findings highlight the importance of long-term genetic monitoring in order to disentangle between the processes of drift and selection maintaining adaptive genetic diversity in small populations.
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Affiliation(s)
- B. Karina Montero
- Animal Ecology and ConservationHamburg UniversityHamburgGermany
- Institute of Evolutionary Ecology and Conservation GenomicsUniversity of UlmUlmGermany
| | | | | | | | | | - Kerstin Wilhelm
- Institute of Evolutionary Ecology and Conservation GenomicsUniversity of UlmUlmGermany
| | | | - Simone Sommer
- Institute of Evolutionary Ecology and Conservation GenomicsUniversity of UlmUlmGermany
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17
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Minias P, Pikus E, Anderwald D. Allelic diversity and selection at the MHC class I and class II in a bottlenecked bird of prey, the White-tailed Eagle. BMC Evol Biol 2019; 19:2. [PMID: 30611206 PMCID: PMC6321662 DOI: 10.1186/s12862-018-1338-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 12/17/2018] [Indexed: 01/07/2023] Open
Abstract
Background Genes of the Major Histocompatibility Complex (MHC) are essential for adaptive immune response in vertebrates, as they encode receptors that recognize peptides derived from the processing of intracellular (MHC class I) and extracellular (MHC class II) pathogens. High MHC diversity in natural populations is primarily generated and maintained by pathogen-mediated diversifying and balancing selection. It is, however, debated whether selection at the MHC can counterbalance the effects of drift in bottlenecked populations. The aim of this study was to assess allelic diversity of MHC genes in a recently bottlenecked bird of prey, the White-tailed Eagle Haliaeetus albicilla, as well as to compare mechanisms that shaped the evolution of MHC class I and class II in this species. Results We showed that significant levels of MHC diversity were retained in the core Central European (Polish) population of White-tailed Eagles. Ten MHC class I and 17 MHC class II alleles were recovered in total and individual birds showed high average MHC diversity (3.80 and 6.48 MHC class I and class II alleles per individual, respectively). Distribution of alleles within individuals provided evidence for the presence of at least three class I and five class II loci the White-tailed Eagle, which suggests recent duplication events. MHC class II showed greater sequence polymorphism than MHC class I and there was much stronger signature of diversifying selection acting on MHC class II than class I. Phylogenetic analysis provided evidence for trans-species similarity of class II, but not class I, sequences, which is likely consistent with stronger balancing selection at MHC class II. Conclusions Relatively high MHC diversity retained in the White-tailed Eagles from northern Poland reinforces high conservation value of local eagle populations. At the same time, our study is the first to demonstrate contrasting patterns of allelic diversity and selection at MHC class I and class II in an accipitrid species, supporting the hypothesis that different mechanisms can shape evolutionary trajectories of MHC class I and class II genes. Electronic supplementary material The online version of this article (10.1186/s12862-018-1338-3) contains supplementary material, which is available to authorized users.
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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.
| | - Ewa Pikus
- Department of Biodiversity Studies and Bioeducation, Faculty of Biology and Environmental Protection, University of Łódź, Banacha 1/3, 90-237, Łódź, Poland
| | - Dariusz Anderwald
- Eagle Conservation Committee, Niepodległości 53/55, 10-044, Olsztyn, Poland
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18
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Athrey G, Faust N, Hieke ASC, Brisbin IL. Effective population sizes and adaptive genetic variation in a captive bird population. PeerJ 2018; 6:e5803. [PMID: 30356989 PMCID: PMC6196071 DOI: 10.7717/peerj.5803] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/21/2018] [Indexed: 12/31/2022] Open
Abstract
Captive populations are considered a key component of ex situ conservation programs. Research on multiple taxa has shown the differential success of maintaining demographic versus genetic stability and viability in captive populations. In typical captive populations, usually founded by few or related individuals, genetic diversity can be lost and inbreeding can accumulate rapidly, calling into question their ultimate utility for release into the wild. Furthermore, domestication selection for survival in captive conditions is another concern. Therefore, it is crucial to understand the dynamics of population sizes, particularly the effective population size, and genetic diversity at non-neutral and adaptive loci in captive populations. In this study, we assessed effective population sizes and genetic variation at both neutral microsatellite markers, as well as SNP variants from the MHC-B locus of a captive Red Junglefowl population. This population represents a rare instance of a population with a well-documented history in captivity, following a realistic scenario of chain-of-custody, unlike many captive lab populations. Our analyses, which included 27 individuals comprising the entirety of one captive population show very low neutral and adaptive genetic variation, as well as low effective sizes, which correspond with the known demographic history. Finally, our study also shows the divergent impacts of small effective size and inbreeding in captive populations on microsatellite versus adaptive genetic variation in the MHC-B locus. Our study provides insights into the difficulties of maintaining adaptive genetic variation in small captive populations.
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Affiliation(s)
- Giridhar Athrey
- Department of Poultry Science, Texas A&M University, College Station, TX, United States of America.,Faculty of Ecology and Evolutionary Biology, Texas A&M University, College Station, TX, United States of America
| | - Nikolas Faust
- Department of Poultry Science, Texas A&M University, College Station, TX, United States of America
| | | | - I Lehr Brisbin
- Savannah River Ecology Lab, Aiken, SC, United States of America
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19
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Jost L, Archer F, Flanagan S, Gaggiotti O, Hoban S, Latch E. Differentiation measures for conservation genetics. Evol Appl 2018; 11:1139-1148. [PMID: 30026802 PMCID: PMC6050183 DOI: 10.1111/eva.12590] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 12/08/2017] [Indexed: 12/04/2022] Open
Abstract
We compare the two main classes of measures of population structure in genetics: (i) fixation measures such as FST,GST, and θ and (ii) allelic differentiation measures such as Jost's D and entropy differentiation. These two groups of measures quantify complementary aspects of population structure, which have no necessary relationship with each other. We focus especially on empirical aspects of population structure relevant to conservation analyses. At the empirical level, the first set of measures quantify nearness to fixation, while the second set of measures quantify relative degree of allelic differentiation. The two sets of measures do not compete with each other. Fixation measures are often misinterpreted as measures of allelic differentiation in conservation applications; we give examples and theoretical explanations showing why this interpretation can mislead. This misinterpretation has led to the mistaken belief that the absolute number of migrants determines allelic differentiation between demes when mutation rate is low; we show that in the finite island model, the absolute number of migrants determines nearness to fixation, not allelic differentiation. We show that a different quantity, the factor that controls Jost's D, is a good predictor of the evolution of the actual genetic divergence between demes at equilibrium in this model. We also show that when conservation decisions require judgments about differences in genetic composition between demes, allelic differentiation measures should be used instead of fixation measures. Allelic differentiation of fast-mutating markers can be used to rank pairs or sets of demes according to their differentiation, but the allelic differentiation at coding loci of interest should be directly measured in order to judge its actual magnitude at these loci.
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Affiliation(s)
| | | | - Sarah Flanagan
- National Institute for Mathematical and Biological SynthesisUniversity of TennesseeKnoxvilleTNUSA
| | - Oscar Gaggiotti
- School of BiologyScottish Oceans InstituteUniversity of St AndrewsSt AndrewsUK
| | | | - Emily Latch
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukeeWIUSA
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20
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Pearson SK, Bull CM, Gardner MG. Selection outweighs drift at a fine scale: Lack of MHC differentiation within a family living lizard across geographically close but disconnected rocky outcrops. Mol Ecol 2018; 27:2204-2214. [PMID: 29603473 DOI: 10.1111/mec.14571] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 02/26/2018] [Accepted: 03/01/2018] [Indexed: 11/30/2022]
Abstract
The highly polymorphic genes of the major histocompatibility complex (MHC) are involved in disease resistance, mate choice and kin recognition. Therefore, they are widely used markers for investigating adaptive variation. Although selection is the key driver, gene flow and genetic drift also influence adaptive genetic variation, sometimes in opposing ways and with consequences for adaptive potential. To further understand the processes that generate MHC variation, it is helpful to compare variation at the MHC with that at neutral genetic loci. Differences in MHC and neutral genetic variation are useful for inferring the relative influence of selection, gene flow and drift on MHC variation. To date, such investigations have usually been undertaken at a broad spatial scale. Yet, evolutionary and ecological processes can occur at a fine spatial scale, particularly in small or fragmented populations. We investigated spatial patterns of MHC variation among three geographically close, naturally discrete, sampling sites of Egernia stokesii, an Australian lizard. The MHC of E. stokesii has recently been characterized, and there is evidence for historical selection on the MHC. We found E. stokesii MHC weakly differentiated among sites compared to microsatellites, suggesting selection, acting similarly at each site, has outweighed any effects of low gene flow or of genetic drift on E. stokesii MHC variation. Our findings demonstrate the strength of selection in shaping patterns of MHC variation or consistency at a fine spatial scale.
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Affiliation(s)
- Sarah K Pearson
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - C Michael Bull
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Michael G Gardner
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia.,Evolutionary Biology Unit, South Australian Museum, Adelaide, SA, Australia
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21
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Lighten J, Papadopulos AST, Mohammed RS, Ward BJ, G Paterson I, Baillie L, Bradbury IR, Hendry AP, Bentzen P, van Oosterhout C. Evolutionary genetics of immunological supertypes reveals two faces of the Red Queen. Nat Commun 2017; 8:1294. [PMID: 29101318 PMCID: PMC5670221 DOI: 10.1038/s41467-017-01183-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 08/23/2017] [Indexed: 11/09/2022] Open
Abstract
Red Queen host-parasite co-evolution can drive adaptations of immune genes by positive selection that erodes genetic variation (Red Queen arms race) or results in a balanced polymorphism (Red Queen dynamics) and long-term preservation of genetic variation (trans-species polymorphism). These two Red Queen processes are opposite extremes of the co-evolutionary spectrum. Here we show that both Red Queen processes can operate simultaneously by analysing the major histocompatibility complex (MHC) in guppies (Poecilia reticulata and P. obscura) and swamp guppies (Micropoecilia picta). Sub-functionalisation of MHC alleles into 'supertypes' explains how polymorphisms persist during rapid host-parasite co-evolution. Simulations show the maintenance of supertypes as balanced polymorphisms, consistent with Red Queen dynamics, whereas alleles within supertypes are subject to positive selection in a Red Queen arms race. Building on the divergent allele advantage hypothesis, we show that functional aspects of allelic diversity help to elucidate the evolution of polymorphic genes involved in Red Queen co-evolution.
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Affiliation(s)
- Jackie Lighten
- School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK.
| | - Alexander S T Papadopulos
- Molecular Ecology and Fisheries Genetics Laboratory, Environment Centre Wales, School of Biological Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - Ryan S Mohammed
- Department of Life Sciences, The University of the West Indies, St Augustine, Trinidad and Tobago
| | - Ben J Ward
- Earlham Institute, Norwich Research Park Innovation Centre, Colney Lane, Norwich, NR4 7UZ, UK
| | - Ian G Paterson
- Marine Gene Probe Laboratory, Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS, Canada, B3H 4R2
| | - Lyndsey Baillie
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Ian R Bradbury
- Marine Gene Probe Laboratory, Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS, Canada, B3H 4R2.,Science Branch, Department of Fisheries and Oceans Canada, 80 East White Hills Road, St. John's, NL, Canada, A1C 5X1
| | - Andrew P Hendry
- McGill University, 859 Sherbrooke Street West, Montreal, QC, Canada, H3A 0C4.,Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, QC, Canada, H3A 0C4
| | - Paul Bentzen
- Marine Gene Probe Laboratory, Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS, Canada, B3H 4R2
| | - Cock van Oosterhout
- School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK.
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22
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Cortázar-Chinarro M, Lattenkamp EZ, Meyer-Lucht Y, Luquet E, Laurila A, Höglund J. Drift, selection, or migration? Processes affecting genetic differentiation and variation along a latitudinal gradient in an amphibian. BMC Evol Biol 2017; 17:189. [PMID: 28806900 PMCID: PMC5557520 DOI: 10.1186/s12862-017-1022-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 07/26/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Past events like fluctuations in population size and post-glacial colonization processes may influence the relative importance of genetic drift, migration and selection when determining the present day patterns of genetic variation. We disentangle how drift, selection and migration shape neutral and adaptive genetic variation in 12 moor frog populations along a 1700 km latitudinal gradient. We studied genetic differentiation and variation at a MHC exon II locus and a set of 18 microsatellites. RESULTS Using outlier analyses, we identified the MHC II exon 2 (corresponding to the β-2 domain) locus and one microsatellite locus (RCO8640) to be subject to diversifying selection, while five microsatellite loci showed signals of stabilizing selection among populations. STRUCTURE and DAPC analyses on the neutral microsatellites assigned populations to a northern and a southern cluster, reflecting two different post-glacial colonization routes found in previous studies. Genetic variation overall was lower in the northern cluster. The signature of selection on MHC exon II was weaker in the northern cluster, possibly as a consequence of smaller and more fragmented populations. CONCLUSION Our results show that historical demographic processes combined with selection and drift have led to a complex pattern of differentiation along the gradient where some loci are more divergent among populations than predicted from drift expectations due to diversifying selection, while other loci are more uniform among populations due to stabilizing selection. Importantly, both overall and MHC genetic variation are lower at northern latitudes. Due to lower evolutionary potential, the low genetic variation in northern populations may increase the risk of extinction when confronted with emerging pathogens and climate change.
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Affiliation(s)
- Maria Cortázar-Chinarro
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden.
| | - Ella Z Lattenkamp
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
- Present address: Department of Neurogenetics of Vocal Communication, Max Planck Institute of Psycholinguistics, Box 310, 6500, Nijmegen, Netherlands
| | - Yvonne Meyer-Lucht
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
| | - Emilien Luquet
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
- Present address: Université Claude Bernard - Lyon I, CNRS, UMR 5023 - LEHNA, 3-6, rue Raphaël Dubois - Bâtiments Darwin C and Forel, 69622 Villeurbanne Cedex 43, Boulevard du 11 novembre, 1918, Lyon, France
| | - Anssi Laurila
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
| | - Jacob Höglund
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
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23
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Identification, genealogical structure and population genetics of S-alleles in Malus sieversii, the wild ancestor of domesticated apple. Heredity (Edinb) 2017. [PMID: 28635965 DOI: 10.1038/hdy.2017.28] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The self-incompatibility (SI) gene that is specifically expressed in pistils encodes the SI-associated ribonuclease (S-RNase), functioning as the female-specificity determinant of a gametophytic SI system. Despite extensive surveys in Malus domestica, the S-alleles have not been fully investigated for Malus sieversii, the primary wild ancestor of the domesticated apple. Here we screened the M. sieversii S-alleles via PCR amplification and sequencing, and identified 14 distinct alleles in this species. By contrast, nearly 40 are present in its close wild relative, Malus sylvestris. We further sequenced 8 nuclear genes to provide a neutral reference, and investigated the evolution of S-alleles via genealogical and population genetic analyses. Both shared ancestral polymorphism and an excess of non-synonymous substitution were detected in the S-RNases of the tribe Maleae in Rosaceae, indicating the action of long-term balancing selection. Approximate Bayesian Computations based on the reference neutral loci revealed a severe bottleneck in four of the six studied M. sieversii populations, suggesting that the low number of S-alleles found in this species is mainly the result of diversity loss due to a drastic population contraction. Such a bottleneck may lead to ambiguous footprints of ongoing balancing selection detected at the S-locus. This study not only elucidates the constituents and number of S-alleles in M. sieversii but also illustrates the potential utility of S-allele number shifts in demographic inference for self-incompatible plant species.
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24
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Conservation in the southern edge of Tetrao urogallus distribution: Gene flow despite fragmentation in the stronghold of the Cantabrian capercaillie. EUR J WILDLIFE RES 2017. [DOI: 10.1007/s10344-017-1110-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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25
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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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26
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Gilroy DL, Phillips KP, Richardson DS, van Oosterhout C. Toll-like receptor variation in the bottlenecked population of the Seychelles warbler: computer simulations see the 'ghost of selection past' and quantify the 'drift debt'. J Evol Biol 2017; 30:1276-1287. [PMID: 28370771 DOI: 10.1111/jeb.13077] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 03/21/2017] [Indexed: 01/09/2023]
Abstract
Balancing selection can maintain immunogenetic variation within host populations, but detecting its signal in a postbottlenecked population is challenging due to the potentially overriding effects of drift. Toll-like receptor genes (TLRs) play a fundamental role in vertebrate immune defence and are predicted to be under balancing selection. We previously characterized variation at TLR loci in the Seychelles warbler (Acrocephalus sechellensis), an endemic passerine that has undergone a historical bottleneck. Five of seven TLR loci were polymorphic, which is in sharp contrast to the low genomewide variation observed. However, standard population genetic statistical methods failed to detect a contemporary signature of selection at any TLR locus. We examined whether the observed TLR polymorphism could be explained by neutral evolution, simulating the population's demography in the software DIYABC. This showed that the posterior distributions of mutation rates had to be unrealistically high to explain the observed genetic variation. We then conducted simulations with an agent-based model using typical values for the mutation rate, which indicated that weak balancing selection has acted on the three TLR genes. The model was able to detect evidence of past selection elevating TLR polymorphism in the prebottleneck populations, but was unable to discern any effects of balancing selection in the contemporary population. Our results show drift is the overriding evolutionary force that has shaped TLR variation in the contemporary Seychelles warbler population, and the observed TLR polymorphisms might be merely the 'ghost of selection past'. Forecast models predict immunogenetic variation in this species will continue to be eroded in the absence of contemporary balancing selection. Such 'drift debt' occurs when a gene pool has not yet reached its new equilibrium level of polymorphism, and this loss could be an important threat to many recently bottlenecked populations.
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Affiliation(s)
- D L Gilroy
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - K P Phillips
- School of Biological Sciences, University of East Anglia, Norwich, UK.,Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - D S Richardson
- School of Biological Sciences, University of East Anglia, Norwich, UK.,Nature Seychelles, Mahe, Republic of Seychelles
| | - C van Oosterhout
- School of Environmental Sciences, University of East Anglia, Norwich, UK
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27
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McKnight DT, Schwarzkopf L, Alford RA, Bower DS, Zenger KR. Effects of emerging infectious diseases on host population genetics: a review. CONSERV GENET 2017. [DOI: 10.1007/s10592-017-0974-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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28
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Littleford-Colquhoun BL, Clemente C, Whiting MJ, Ortiz-Barrientos D, Frère CH. Archipelagos of the Anthropocene: rapid and extensive differentiation of native terrestrial vertebrates in a single metropolis. Mol Ecol 2017; 26:2466-2481. [DOI: 10.1111/mec.14042] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/12/2016] [Accepted: 01/04/2017] [Indexed: 12/24/2022]
Affiliation(s)
| | - Christofer Clemente
- School of Science and Engineering; University of the Sunshine Coast; Maroochydore DC Qld 4556 Australia
| | - Martin J. Whiting
- Department of Biological Sciences; Macquarie University; Sydney NSW 2109 Australia
| | | | - Celine H. Frère
- School of Science and Engineering; University of the Sunshine Coast; Maroochydore DC Qld 4556 Australia
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29
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Rico Y, Ethier DM, Davy CM, Sayers J, Weir RD, Swanson BJ, Nocera JJ, Kyle CJ. Spatial patterns of immunogenetic and neutral variation underscore the conservation value of small, isolated American badger populations. Evol Appl 2016; 9:1271-1284. [PMID: 27877205 PMCID: PMC5108218 DOI: 10.1111/eva.12410] [Citation(s) in RCA: 17] [Impact Index Per Article: 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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30
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Gilroy DL, van Oosterhout C, Komdeur J, Richardson DS. Toll-like receptor variation in the bottlenecked population of the endangered Seychelles warbler. Anim Conserv 2016. [DOI: 10.1111/acv.12307] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- D. L. Gilroy
- School of Biological Sciences; Norwich Research Park; University of East Anglia; Norwich UK
| | - C. van Oosterhout
- School of Environmental Sciences; Norwich Research Park; University of East Anglia; Norwich UK
| | - J. Komdeur
- Behavioural Ecology and Self-Organization; Centre for Ecological and Evolutionary Studies; University of Groningen; Groningen The Netherlands
| | - D. S. Richardson
- School of Biological Sciences; Norwich Research Park; University of East Anglia; Norwich UK
- Nature Seychelles; Mahe Republic of Seychelles
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31
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Vlček J, Hoeck PEA, Keller LF, Wayhart JP, Dolinová I, Štefka J. Balancing selection and genetic drift create unusual patterns of MHCIIβ variation in Galápagos mockingbirds. Mol Ecol 2016; 25:4757-72. [PMID: 27545344 DOI: 10.1111/mec.13807] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 07/28/2016] [Accepted: 08/08/2016] [Indexed: 01/01/2023]
Abstract
The extracellular subunit of the major histocompatibility complex MHCIIβ plays an important role in the recognition of pathogens and the initiation of the adaptive immune response of vertebrates. It is widely accepted that pathogen-mediated selection in combination with neutral micro-evolutionary forces (e.g. genetic drift) shape the diversity of MHCIIβ, but it has proved difficult to determine the relative effects of these forces. We evaluated the effect of genetic drift and balancing selection on MHCIIβ diversity in 12 small populations of Galápagos mockingbirds belonging to four different species, and one larger population of the Northern mockingbird from the continental USA. After genotyping MHCIIβ loci by high-throughput sequencing, we applied a correlational approach to explore the relationships between MHCIIβ diversity and population size by proxy of island size. As expected when drift predominates, we found a positive effect of population size on the number of MHCIIβ alleles present in a population. However, the number of MHCIIβ alleles per individual and number of supertypes were not correlated with population size. This discrepancy points to an interesting feature of MHCIIβ diversity dynamics: some levels of diversity might be shaped by genetic drift while others are independent and possibly maintained by balancing selection.
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Affiliation(s)
- Jakub Vlček
- Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 1670, České Budějovice, Czech Republic
| | - Paquita E A Hoeck
- Institute for Conservation Research, San Diego Zoo Global, 15600 San Pasqual Valley Road, Escondido, CA, 92027, USA
| | - Lukas F Keller
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Jessica P Wayhart
- Institute for Conservation Research, San Diego Zoo Global, 15600 San Pasqual Valley Road, Escondido, CA, 92027, USA
| | - Iva Dolinová
- Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Bendlova 7, Liberec, Czech Republic
| | - Jan Štefka
- Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic. .,Faculty of Science, University of South Bohemia, Branišovská 1670, České Budějovice, Czech Republic.
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32
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Jaeger CP, Duvall MR, Swanson BJ, Phillips CA, Dreslik MJ, Baker SJ, King RB. Microsatellite and major histocompatibility complex variation in an endangered rattlesnake, the Eastern Massasauga (Sistrurus catenatus). Ecol Evol 2016; 6:3991-4003. [PMID: 27516858 PMCID: PMC4874855 DOI: 10.1002/ece3.2159] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 01/18/2023] Open
Abstract
Genetic diversity is fundamental to maintaining the long-term viability of populations, yet reduced genetic variation is often associated with small, isolated populations. To examine the relationship between demography and genetic variation, variation at hypervariable loci (e.g., microsatellite DNA loci) is often measured. However, these loci are selectively neutral (or near neutral) and may not accurately reflect genomewide variation. Variation at functional trait loci, such as the major histocompatibility complex (MHC), can provide a better assessment of adaptive genetic variation in fragmented populations. We compared patterns of microsatellite and MHC variation across three Eastern Massasauga (Sistrurus catenatus) populations representing a gradient of demographic histories to assess the relative roles of natural selection and genetic drift. Using 454 deep amplicon sequencing, we identified 24 putatively functional MHC IIB exon 2 alleles belonging to a minimum of six loci. Analysis of synonymous and nonsynonymous substitution rates provided evidence of historical positive selection at the nucleotide level, and Tajima's D provided support for balancing selection in each population. As predicted, estimates of microsatellite allelic richness, observed, heterozygosity, and expected heterozygosity varied among populations in a pattern qualitatively consistent with demographic history and abundance. While MHC allelic richness at the population and individual levels revealed similar trends, MHC nucleotide diversity was unexpectedly high in the smallest population. Overall, these results suggest that genetic variation in the Eastern Massasauga populations in Illinois has been shaped by multiple evolutionary mechanisms. Thus, conservation efforts should consider both neutral and functional genetic variation when managing captive and wild Eastern Massasauga populations.
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Affiliation(s)
- Collin P. Jaeger
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
| | - Melvin R. Duvall
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
| | - Bradley J. Swanson
- Department of BiologyCentral Michigan UniversityMt. PleasantMichigan48859
| | - Christopher A. Phillips
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Michael J. Dreslik
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Sarah J. Baker
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Richard B. King
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
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33
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Faulks LK, Östman Ö. Adaptive major histocompatibility complex (MHC) and neutral genetic variation in two native Baltic Sea fishes (perch Perca fluviatilis and zander Sander lucioperca) with comparisons to an introduced and disease susceptible population in Australia (P. fluviatilis): assessing the risk of disease epidemics. JOURNAL OF FISH BIOLOGY 2016; 88:1564-1583. [PMID: 26940068 DOI: 10.1111/jfb.12930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 01/29/2016] [Indexed: 06/05/2023]
Abstract
This study assessed the major histocompatibility complex (MHC) and neutral genetic variation and structure in two percid species, perch Perca fluviatilis and zander Sander lucioperca, in a unique brackish ecosystem, the Baltic Sea. In addition, to assess the importance of MHC diversity to disease susceptibility in these populations, comparisons were made to an introduced, disease susceptible, P. fluviatilis population in Australia. Eighty-three MHC class II B exon 2 variants were amplified: 71 variants from 92 P. fluviatilis samples, and 12 variants from 82 S. lucioperca samples. Microsatellite and MHC data revealed strong spatial genetic structure in S. lucioperca, but not P. fluviatilis, across the Baltic Sea. Both microsatellite and MHC data showed higher levels of genetic diversity in P. fluviatilis from the Baltic Sea compared to Australia, which may have facilitated the spread of an endemic virus, EHNV in the Australian population. The relatively high levels of genetic variation in the Baltic Sea populations, together with spatial genetic structure, however, suggest that there currently seems to be little risk of disease epidemics in this system. To ensure this remains the case in the face of ongoing environmental changes, fisheries and habitat disturbance, the conservation of local-scale genetic variation is recommended.
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Affiliation(s)
- L K Faulks
- Department of Ecology and Genetics - Animal Ecology, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
| | - Ö Östman
- Department of Aquatic Resources - Institute of Coastal Research, Swedish University of Agricultural Sciences, Skolvägen 6, 74242, Öregrund, Sweden
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34
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Cobble KR, Califf KJ, Stone NE, Shuey MM, Birdsell DN, Colman RE, Schupp JM, Aziz M, Van Andel R, Rocke TE, Wagner DM, Busch JD. Genetic variation at the MHC DRB1 locus is similar across Gunnison's prairie dog (Cynomys gunnisoni) colonies regardless of plague history. Ecol Evol 2016; 6:2624-51. [PMID: 27066243 PMCID: PMC4798151 DOI: 10.1002/ece3.2077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/18/2016] [Accepted: 02/22/2016] [Indexed: 01/16/2023] Open
Abstract
Yersinia pestis was introduced to North America around 1900 and leads to nearly 100% mortality in prairie dog (Cynomys spp.) colonies during epizootic events, which suggests this pathogen may exert a strong selective force. We characterized genetic diversity at an MHC class II locus (DRB1) in Gunnison's prairie dog (C. gunnisoni) and quantified population genetic structure at the DRB1 versus 12 microsatellite loci in three large Arizona colonies. Two colonies, Seligman (SE) and Espee Ranch (ES), have experienced multiple plague‐related die‐offs in recent years, whereas plague has never been documented at Aubrey Valley (AV). We found fairly low allelic diversity at the DRB1 locus, with one allele (DRB1*01) at high frequency (0.67–0.87) in all colonies. Two other DRB1 alleles appear to be trans‐species polymorphisms shared with the black‐tailed prairie dog (C. ludovicianus), indicating that these alleles have been maintained across evolutionary time frames. Estimates of genetic differentiation were generally lower at the MHC locus (FST = 0.033) than at microsatellite markers (FST = 0.098). The reduced differentiation at DRB1 may indicate that selection has been important for shaping variation at MHC loci, regardless of the presence or absence of plague in recent decades. However, genetic drift has probably also influenced the DRB1 locus because its level of differentiation was not different from that of microsatellites in an FST outlier analysis. We then compared specific MHC alleles to plague survivorship in 60 C. gunnisoni that had been experimentally infected with Y. pestis. We found that survival was greater in individuals that carried at least one copy of the most common allele (DRB1*01) compared to those that did not (60% vs. 20%). Although the sample sizes of these two groups were unbalanced, this result suggests the possibility that this MHC class II locus, or a nearby linked gene, could play a role in plague survival.
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Affiliation(s)
- Kacy R Cobble
- Center for Microbial Genetics and Genomics Northern Arizona University PO Box 4073 Flagstaff Arizona 86011 USA
| | - Katy J Califf
- Center for Microbial Genetics and Genomics Northern Arizona University PO Box 4073 Flagstaff Arizona 86011 USA
| | - Nathan E Stone
- Center for Microbial Genetics and Genomics Northern Arizona University PO Box 4073 Flagstaff Arizona 86011 USA
| | - Megan M Shuey
- Center for Microbial Genetics and Genomics Northern Arizona University PO Box 4073 Flagstaff Arizona 86011 USA
| | - Dawn N Birdsell
- Center for Microbial Genetics and Genomics Northern Arizona University PO Box 4073 Flagstaff Arizona 86011 USA
| | - Rebecca E Colman
- Translational Genomics Research Institute North 3051 W. Shamrell Blvd #106 Flagstaff Arizona 86001 USA
| | - James M Schupp
- Translational Genomics Research Institute North 3051 W. Shamrell Blvd #106 Flagstaff Arizona 86001 USA
| | - Maliha Aziz
- Translational Genomics Research Institute North 3051 W. Shamrell Blvd #106 Flagstaff Arizona 86001 USA
| | - Roger Van Andel
- University of California Berkeley MC 7150 Berkeley California 94720 USA
| | - Tonie E Rocke
- United States Geological Survey National Wildlife Health Center 6006 Schroeder Road Madison Wisconsin 53711 USA
| | - David M Wagner
- Center for Microbial Genetics and Genomics Northern Arizona University PO Box 4073 Flagstaff Arizona 86011 USA
| | - Joseph D Busch
- Center for Microbial Genetics and Genomics Northern Arizona University PO Box 4073 Flagstaff Arizona 86011 USA
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35
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Adaptive and neutral genetic differentiation among Scottish and endangered Irish red grouse (Lagopus lagopus scotica). CONSERV GENET 2016. [DOI: 10.1007/s10592-016-0810-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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36
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Knafler GJ, Ortiz-Catedral L, Jackson B, Varsani A, Grueber CE, Robertson BC, Jamieson IG. Comparison of beak and feather disease virus prevalence and immunity-associated genetic diversity over time in an island population of red-crowned parakeets. Arch Virol 2015; 161:811-20. [PMID: 26699786 DOI: 10.1007/s00705-015-2717-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Accepted: 12/03/2015] [Indexed: 11/30/2022]
Abstract
Pathogen outbreaks in the wild can contribute to a population's extinction risk. Concern over the effects of pathogen outbreaks in wildlife is amplified in small, threatened populations, where degradation of genetic diversity may hinder natural selection for enhanced immunocompetence. Beak and feather disease virus (BFDV) was detected for the first time in an island population of red-crowned parakeets (Cyanoramphus novaezelandiae) in 2008 on Little Barrier Island (Hauturu-o-Toi) of New Zealand. By 2013, the prevalence of the viral infection had significantly decreased within the population. We tested whether the population of red-crowned parakeets showed a selective response to BFDV, using neutral microsatellite and two immunity-associated genetic markers, the major histocompatibility complex (MHC) and Toll-like receptors (TLRs). We found evidence for selection at viral-associated TLR3; however, the ability of TLR3 to elicit an immune response in the presence of BFDV warrants confirmation. Alternatively, because red-crowned parakeet populations are prone to fluctuations in size, the decrease in BFDV prevalence over time may be attributed to the Little Barrier Island population dropping below the density threshold for viral maintenance. Our results highlight that natural processes such as adaptation for enhanced immunocompetence and/or density fluctuations are efficient mechanisms for reducing pathogen prevalence in a threatened, isolated population.
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Affiliation(s)
- Gabrielle J Knafler
- Department of Zoology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
| | - Luis Ortiz-Catedral
- Ecology and Conservation Group, Institute of Natural and Mathematical Sciences, Massey University, Private Bag 102-904, Auckland, New Zealand
| | - Bethany Jackson
- College of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Arvind Varsani
- Centre for Integrative Ecology, Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
- Structural Biology Research Unit, Division of Medical Biochemistry, Department of Clinical Laboratory Sciences, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
- Department of Plant Pathology and Emerging Pathogens Institute, University of Florida, Gainesville, USA
| | - Catherine E Grueber
- Department of Zoology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
- Faculty of Veterinary Science, University of Sydney, Sydney, NSW, Australia
- San Diego Zoo Global, San Diego, USA
| | - Bruce C Robertson
- Department of Zoology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
| | - Ian G Jamieson
- Department of Zoology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
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37
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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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Pavlovska M, Höglund J. Ukrainian Black GrouseTetrao tetrix: Genetic Diversity and Population Structure. WILDLIFE BIOLOGY 2015. [DOI: 10.2981/wlb.00093] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Clozato CL, Mazzoni CJ, Moraes-Barros N, Morgante JS, Sommer S. Spatial pattern of adaptive and neutral genetic diversity across different biomes in the lesser anteater (Tamandua tetradactyla). Ecol Evol 2015; 5:4932-48. [PMID: 26640672 PMCID: PMC4662318 DOI: 10.1002/ece3.1656] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 07/08/2015] [Accepted: 07/13/2015] [Indexed: 01/03/2023] Open
Abstract
The genes of the major histocompatibility complex (MHC) code for proteins involved in antigen recognition and activation of the adaptive immune response and are thought to be regulated by natural selection, especially due to pathogen‐driven selective pressure. In this study, we investigated the spatial distribution of MHC class IIDRB exon 2 gene diversity of the lesser anteater (Tamandua tetradactyla) across five Brazilian biomes using next‐generation sequencing and compared the MHC pattern with that of neutral markers (microsatellites). We found a noticeable high level of diversity in DRB (60 amino acid alleles in 65 individuals) and clear signatures of historical positive selection acting on this gene. Higher allelic richness and proportion of private alleles were found in rain forest biomes, especially Amazon forest, a megadiverse biome, possibly harboring greater pathogen richness as well. Neutral markers, however, showed a similar pattern to DRB, demonstrating the strength of demography as an additional force to pathogen‐driven selection in shaping MHC diversity and structure. This is the first characterization and description of diversity of a MHC gene for any member of the magna‐order Xenarthra, one of the basal lineages of placental mammals.
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Affiliation(s)
- Camila L Clozato
- Laboratório de Biologia Evolutiva e Conservação de Vertebrados Departamento de Genética e Biologia Evolutiva Instituto de Biociências Universidade de São Paulo R. do Matão, 277 05508-090 São Paulo Brasil ; Leibniz-Institute for Zoo and Wildlife Research (IZW) Evolutionary Genetics Alfred- Kowalke-Straße 17 D-10315 Berlin Germany
| | - Camila J Mazzoni
- Leibniz-Institute for Zoo and Wildlife Research (IZW) Evolutionary Genetics Alfred- Kowalke-Straße 17 D-10315 Berlin Germany ; Berlin Center for Genomics in Biodiversity Research (BeGenDiv) Koenigin-Luise-Straße. 6-8 D-14195 Berlin Germany
| | - Nadia Moraes-Barros
- Laboratório de Biologia Evolutiva e Conservação de Vertebrados Departamento de Genética e Biologia Evolutiva Instituto de Biociências Universidade de São Paulo R. do Matão, 277 05508-090 São Paulo Brasil ; CIBIO Centro de Investigação em Biodiversidade e Recursos Genéticos InBio Laboratório Associado Universidade do Porto R. Padre Armando Quintas 4485-661 Vairão Portugal
| | - João S Morgante
- Laboratório de Biologia Evolutiva e Conservação de Vertebrados Departamento de Genética e Biologia Evolutiva Instituto de Biociências Universidade de São Paulo R. do Matão, 277 05508-090 São Paulo Brasil
| | - Simone Sommer
- Leibniz-Institute for Zoo and Wildlife Research (IZW) Evolutionary Genetics Alfred- Kowalke-Straße 17 D-10315 Berlin Germany ; Evolutionary Ecology and Conservation Genomics University of Ulm Albert-Einstein Strasse 11 D-89069 Ulm Germany
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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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Magalhães V, Abrantes J, Munõz-Pajares AJ, Esteves PJ. Genetic diversity comparison of the DQA gene in European rabbit (Oryctolagus cuniculus) populations. Immunogenetics 2015; 67:579-90. [PMID: 26307416 DOI: 10.1007/s00251-015-0866-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 08/13/2015] [Indexed: 10/23/2022]
Abstract
The European rabbit (Oryctolagus cuniculus) natural populations within the species native region, the Iberian Peninsula, are considered a reservoir of genetic diversity. Indeed, the Iberia was a Pleistocene refuge to the species and currently two subspecies are found in the peninsula (Oryctolagus cuniculus cuniculus and Oryctolagus cuniculus algirus). The genes of the major histocompatibility complex (MHC) have been substantially studied in wild populations due to their exceptional variability, believed to be pathogen driven. They play an important function as part of the adaptive immune system affecting the individual fitness and population viability. In this study, the MHC variability was assessed by analysing the exon 2 of the DQA gene in several European rabbit populations from Portugal, Spain and France and in domestic breeds. Twenty-eight DQA alleles were detected, among which 18 are described for the first time. The Iberian rabbit populations are well differentiated from the French population and domestic breeds. The Iberian populations retained the higher allelic diversity with the domestic breeds harbouring the lowest; in contrast, the DQA nucleotide diversity was higher in the French population. Signatures of positive selection were detected in four codons which are putative peptide-binding sites and have been previously detected in other mammals. The evolutionary relationships showed instances of trans-species polymorphism. Overall, our results suggest that the DQA in European rabbits is evolving under selection and genetic drift.
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Affiliation(s)
- Vanessa Magalhães
- CIBIO, InBIO - Research Network in Biodiversity and Evolutionary Biology, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas, 4485-661, Vairão, Portugal
| | - Joana Abrantes
- CIBIO, InBIO - Research Network in Biodiversity and Evolutionary Biology, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas, 4485-661, Vairão, Portugal
| | - Antonio Jesús Munõz-Pajares
- CIBIO, InBIO - Research Network in Biodiversity and Evolutionary Biology, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas, 4485-661, Vairão, Portugal
| | - Pedro J Esteves
- CIBIO, InBIO - Research Network in Biodiversity and Evolutionary Biology, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas, 4485-661, Vairão, Portugal. .,Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal. .,Centro de Investigação em Tecnologias da Saúde (CITS), ISPN, CESPU, Gandra, Portugal.
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Quéméré E, Galan M, Cosson JF, Klein F, Aulagnier S, Gilot-Fromont E, Merlet J, Bonhomme M, Hewison AJM, Charbonnel N. Immunogenetic heterogeneity in a widespread ungulate: the European roe deer (Capreolus capreolus). Mol Ecol 2015; 24:3873-87. [PMID: 26120040 DOI: 10.1111/mec.13292] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 06/18/2015] [Accepted: 06/24/2015] [Indexed: 12/25/2022]
Abstract
Understanding how immune genetic variation is shaped by selective and neutral processes in wild populations is of prime importance in both evolutionary biology and epidemiology. The European roe deer (Capreolus capreolus) has considerably expanded its distribution range these last decades, notably by colonizing agricultural landscapes. This range shift is likely to have led to bottlenecks and increased roe deer exposure to a new range of pathogens that until recently predominantly infected humans and domestic fauna. We therefore investigated the historical and contemporary forces that have shaped variability in a panel of genes involved in innate and acquired immunity in roe deer, including Mhc-Drb and genes encoding cytokines or toll-like receptors (TLRs). Together, our results suggest that genetic drift is the main contemporary evolutionary force shaping immunogenetic variation within populations. However, in contrast to the classical view, we found that some innate immune genes involved in micropathogen recognition (e.g. Tlrs) continue to evolve dynamically in roe deer in response to pathogen-mediated positive selection. Most studied Tlrs (Tlr2, Tlr4 and Tlr5) had similarly high levels of amino acid diversity in the three studied populations including one recently established in southwestern France that showed a clear signature of genetic bottleneck. Tlr2 implicated in the recognition of Gram-positive bacteria in domestic ungulates, showed strong evidence of balancing selection. The high immunogenetic variation revealed here implies that roe deer are able to cope with a wide spectrum of pathogens and to respond rapidly to emerging infectious diseases.
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Affiliation(s)
- Erwan Quéméré
- Laboratoire Comportement et Ecologie de la Faune Sauvage (CEFS), INRA UR35, B.P. 52627, 31326, Castanet-Tolosan, France
| | - Maxime Galan
- INRA, UMR CBGP, (INRA/IRD/Cirad/Montpellier SupAgro), Campus International de Baillarguet CS 30016, 34988, Montferrier-sur-Lez Cedex, France
| | - Jean-François Cosson
- INRA, UMR CBGP, (INRA/IRD/Cirad/Montpellier SupAgro), Campus International de Baillarguet CS 30016, 34988, Montferrier-sur-Lez Cedex, France
| | - François Klein
- ONCFS, CNERA Cervidés-Sanglier, 1 Place Exelmans, F-55000, Bar-le-Duc, France
| | - Stéphane Aulagnier
- Laboratoire Comportement et Ecologie de la Faune Sauvage (CEFS), INRA UR35, B.P. 52627, 31326, Castanet-Tolosan, France
| | - Emmanuelle Gilot-Fromont
- Université de Lyon, Université Lyon 1, UMR CNRS, 5558, Villeurbanne, France.,Université de Lyon, VetAgro Sup, Marcy l'Etoile, France
| | - Joël Merlet
- Laboratoire Comportement et Ecologie de la Faune Sauvage (CEFS), INRA UR35, B.P. 52627, 31326, Castanet-Tolosan, France
| | - Maxime Bonhomme
- Laboratoire de Recherches en Sciences Végétales, Université de Toulouse UPS, CNRS UMR5546, Castanet-Tolosan, France
| | - A J Mark Hewison
- Laboratoire Comportement et Ecologie de la Faune Sauvage (CEFS), INRA UR35, B.P. 52627, 31326, Castanet-Tolosan, France
| | - Nathalie Charbonnel
- INRA, UMR CBGP, (INRA/IRD/Cirad/Montpellier SupAgro), Campus International de Baillarguet CS 30016, 34988, Montferrier-sur-Lez Cedex, France
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Kohyama TI, Omote K, Nishida C, Takenaka T, Saito K, Fujimoto S, Masuda R. Spatial and temporal variation at major histocompatibility complex class IIB genes in the endangered Blakiston's fish owl. ZOOLOGICAL LETTERS 2015; 1:13. [PMID: 26605058 PMCID: PMC4657285 DOI: 10.1186/s40851-015-0013-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/25/2015] [Indexed: 06/05/2023]
Abstract
INTRODUCTION Quantifying intraspecific genetic variation in functionally important genes, such as those of the major histocompatibility complex (MHC), is important in the establishment of conservation plans for endangered species. The MHC genes play a crucial role in the vertebrate immune system and generally show high levels of diversity, which is likely due to pathogen-driven balancing selection. The endangered Blakiston's fish owl (Bubo blakistoni) has suffered marked population declines on Hokkaido Island, Japan, during the past several decades due to human-induced habitat loss and fragmentation. We investigated the spatial and temporal patterns of genetic diversity in MHC class IIβ genes in Blakiston's fish owl, using massively parallel pyrosequencing. RESULTS We found that the Blakiston's fish owl genome contains at least eight MHC class IIβ loci, indicating recent gene duplications. An analysis of sequence polymorphism provided evidence that balancing selection acted in the past. The level of MHC variation, however, was low in the current fish owl populations in Hokkaido: only 19 alleles were identified from 174 individuals. We detected considerable spatial differences in MHC diversity among the geographically isolated populations. We also detected a decline of MHC diversity in some local populations during the past decades. CONCLUSIONS Our study demonstrated that the current spatial patterns of MHC variation in Blakiston's fish owl populations have been shaped by loss of variation due to the decline and fragmentation of populations, and that the short-term effects of genetic drift have counteracted the long-term effects of balancing selection.
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Affiliation(s)
- Tetsuo I Kohyama
- />Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Keita Omote
- />Department of Natural History Sciences, Graduate School of Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Chizuko Nishida
- />Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Takeshi Takenaka
- />FILIN, Hachiken 2 Jo Nishi 2, Nishi-ku, Sapporo 063-0842 Japan
| | - Keisuke Saito
- />Institute for Raptor Biomedicine, Kushiro, 084-0922 Japan
| | | | - Ryuichi Masuda
- />Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810 Japan
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Bichet C, Moodley Y, Penn DJ, Sorci G, Garnier S. Genetic structure in insular and mainland populations of house sparrows (Passer domesticus) and their hemosporidian parasites. Ecol Evol 2015; 5:1639-52. [PMID: 25937907 PMCID: PMC4409412 DOI: 10.1002/ece3.1452] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 02/08/2015] [Indexed: 11/07/2022] Open
Abstract
Small and isolated populations usually exhibit low levels of genetic variability, and thus, they are expected to have a lower capacity to adapt to changes in environmental conditions, such as exposure to pathogens and parasites. Comparing the genetic variability of selectively neutral versus functional loci allows one to assess the evolutionary history of populations and their future evolutionary potential. The genes of the major histocompatibility complex (MHC) control immune recognition of parasites, and their unusually high diversity is genes which is likely driven by parasite-mediated balancing selection. Here, we examined diversity and differentiation of neutral microsatellite loci and functional MHC class I genes in house sparrows (Passer domesticus), living in six insular and six mainland populations, and we aimed to determine whether their diversity or differentiation correlates with the diversity and the prevalence of infection of hemosporidian parasites. We found that island bird populations tended to have lower neutral genetic variability, whereas MHC variability gene was similar between island and mainland populations. Similarly, island populations tended to show greater genetic differentiation than mainland populations, especially at microsatellite markers. The maintenance of MHC genetic diversity and its less marked structure in the island populations could be attributed to balancing-selection. The greater MHC differentiation among populations was negatively correlated with similarity in blood parasites (prevalence and diversity of parasite strains) between populations. Even at low prevalence and small geographical scale, haemosporidian parasites might contribute to structure the variability of immune genes among populations of hosts.
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Affiliation(s)
- Coraline Bichet
- Biogéosciences, UMR CNRS 6282, Université de Bourgogne 6 Boulevard Gabriel, 21000, Dijon, France ; Laboratoire LBBE, UMR CNRS 5558, Université Claude Bernard Lyon 1 bâtiment Mendel, 43 boulevard du 11 novembre 1918, 69622, Villeurbanne Cedex, France
| | - Yoshan Moodley
- Department of Zoology, University of Venda Private Bag X5050, Thohoyandou, 0950, South Africa ; Department of Integrative Biology and Evolution, Konrad-Lorenz-Institute of Ethology, University of Veterinarian Medicine Vienna Savoyenstr. 1a, A-1160, Vienna, Austria
| | - Dustin J Penn
- Department of Integrative Biology and Evolution, Konrad-Lorenz-Institute of Ethology, University of Veterinarian Medicine Vienna Savoyenstr. 1a, A-1160, Vienna, Austria
| | - Gabriele Sorci
- Biogéosciences, UMR CNRS 6282, Université de Bourgogne 6 Boulevard Gabriel, 21000, Dijon, France
| | - Stéphane Garnier
- Biogéosciences, UMR CNRS 6282, Université de Bourgogne 6 Boulevard Gabriel, 21000, Dijon, France
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McMahon BJ, Teeling EC, Höglund J. How and why should we implement genomics into conservation? Evol Appl 2014; 7:999-1007. [PMID: 25553063 PMCID: PMC4231591 DOI: 10.1111/eva.12193] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 06/19/2014] [Indexed: 12/14/2022] Open
Abstract
Conservation genetics has provided important information into the dynamics of endangered populations. The rapid development of genomic methods has posed an important question, namely where do genetics and genomics sit in relation to their application in the conservation of species? Although genetics can answer a number of relevant questions related to conservation, the argument for the application of genomics is not yet fully exploited. Here, we explore the transition and rationale for the move from genetic to genomic research in conservation biology and the utility of such research. We explore the idea of a 'conservation prior' and how this can be determined by genomic data and used in the management of populations. We depict three different conservation scenarios and describe how genomic data can drive management action in each situation. We conclude that the most effective applications of genomics will be to inform stakeholders with the aim of avoiding 'emergency room conservation'.
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Affiliation(s)
- Barry J McMahon
- UCD School of Agriculture & Food Science, University College DublinBelfield, Dublin 4, Ireland
| | - Emma C Teeling
- UCD School of Biology & Environmental Science, University College DublinBelfield, Dublin 4, Ireland
| | - Jacob Höglund
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala UniversityUppsala, Sweden
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Role of selection versus neutral processes determining genetic variation in a small mammal along a climatic gradient in southern Africa. Evol Ecol 2014. [DOI: 10.1007/s10682-014-9731-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Exonic versus intronic SNPs: contrasting roles in revealing the population genetic differentiation of a widespread bird species. Heredity (Edinb) 2014; 114:1-9. [PMID: 25074575 DOI: 10.1038/hdy.2014.59] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 05/22/2014] [Accepted: 06/03/2014] [Indexed: 11/08/2022] Open
Abstract
Recent years have seen considerable progress in applying single nucleotide polymorphisms (SNPs) to population genetics studies. However, relatively few have attempted to use them to study the genetic differentiation of wild bird populations and none have examined possible differences of exonic and intronic SNPs in these studies. Here, using 144 SNPs, we examined population genetic differentiation in the saker falcon (Falco cherrug) across Eurasia. The position of each SNP was verified using the recently sequenced saker genome with 108 SNPs positioned within the introns of 10 fragments and 36 SNPs in the exons of six genes, comprising MHC, MC1R and four others. In contrast to intronic SNPs, both Bayesian clustering and principal component analyses using exonic SNPs consistently revealed two genetic clusters, within which the least admixed individuals were found in Europe/central Asia and Qinghai (China), respectively. Pairwise D analysis for exonic SNPs showed that the two populations were significantly differentiated and between the two clusters the frequencies of five SNP markers were inferred to be influenced by selection. Central Eurasian populations clustered in as intermediate between the two main groups, consistent with their geographic position. But the westernmost populations of central Europe showed evidence of demographic isolation. Our work highlights the importance of functional exonic SNPs for studying population genetic pattern in a widespread avian species.
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Segelbacher G, Strand TM, Quintela M, Axelsson T, Jansman HAH, Koelewijn HP, Höglund J. Analyses of historical and current populations of black grouse in Central Europe reveal strong effects of genetic drift and loss of genetic diversity. CONSERV GENET 2014. [DOI: 10.1007/s10592-014-0610-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Fietz J, Tomiuk J, Loeschcke V, Weis-Dootz T, Segelbacher G. Genetic consequences of forest fragmentation for a highly specialized arboreal mammal--the edible dormouse. PLoS One 2014; 9:e88092. [PMID: 24505390 PMCID: PMC3913767 DOI: 10.1371/journal.pone.0088092] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 01/08/2014] [Indexed: 11/23/2022] Open
Abstract
Habitat loss and fragmentation represent the most serious extinction threats for many species and have been demonstrated to be especially detrimental for mammals. Particularly, highly specialized species with low dispersal abilities will encounter a high risk of extinction in fragmented landscapes. Here we studied the edible dormouse (Glis glis), a small arboreal mammal that is distributed throughout Central Europe, where forests are mostly fragmented at different spatial scales. The aim of this study was to investigate the effect of habitat fragmentation on genetic population structures using the example of edible dormouse populations inhabiting forest fragments in south western Germany. We genotyped 380 adult individuals captured between 2001 and 2009 in four different forest fragments and one large continuous forest using 14 species-specific microsatellites. We hypothesised, that populations in small forest patches have a lower genetic diversity and are more isolated compared to populations living in continuous forests. In accordance with our expectations we found that dormice inhabiting forest fragments were isolated from each other. Furthermore, their genetic population structure was more unstable over the study period than in the large continuous forest. Even though we could not detect lower genetic variability within individuals inhabiting forest fragments, strong genetic isolation and an overall high risk to mate with close relatives might be precursors to a reduced genetic variability and the onset of inbreeding depression. Results of this study highlight that connectivity among habitat fragments can already be strongly hampered before genetic erosion within small and isolated populations becomes evident.
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Affiliation(s)
- Joanna Fietz
- Animal Husbandry and Animal Breeding, University of Hohenheim, Stuttgart, Germany
- * E-mail:
| | - Jürgen Tomiuk
- Department of Biosciences, Integrative Ecology and Evolution, Aarhus University, Aarhus, Denmark
| | - Volker Loeschcke
- Department of Biosciences, Integrative Ecology and Evolution, Aarhus University, Aarhus, Denmark
| | - Tanja Weis-Dootz
- Institute of Experimental Ecology, University of Ulm, Ulm, Germany
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Niskanen AK, Kennedy LJ, Ruokonen M, Kojola I, Lohi H, Isomursu M, Jansson E, Pyhäjärvi T, Aspi J. Balancing selection and heterozygote advantage in major histocompatibility complex loci of the bottlenecked Finnish wolf population. Mol Ecol 2014; 23:875-89. [DOI: 10.1111/mec.12647] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 12/19/2013] [Accepted: 12/20/2013] [Indexed: 02/03/2023]
Affiliation(s)
- A. K. Niskanen
- Department of Biology; University of Oulu; PO Box 3000 FI-90014 Oulu Finland
| | - L. J. Kennedy
- Centre for Integrated Genomic Medical Research; University of Manchester; Stopford Building Oxford Road Manchester M13 9PT UK
| | - M. Ruokonen
- Department of Biology; University of Oulu; PO Box 3000 FI-90014 Oulu Finland
| | - I. Kojola
- Finnish Game and Fisheries Research Institute; Paavo Havaksen tie 3 PO Box 413 FI-90014 Oulu Finland
| | - H. Lohi
- Department of Veterinary Biosciences; Research Programs Unit; Molecular Neurology; Folkhälsan Institute of Genetics; Biomedicum Helsinki; University of Helsinki; PO Box 63 FI-00014 Helsinki Finland
| | - M. Isomursu
- Fish and Wildlife Health Research Unit; Finnish Food Safety Authority Evira; PO Box 517 FI-90101 Oulu Finland
| | - E. Jansson
- Department of Biology; University of Oulu; PO Box 3000 FI-90014 Oulu Finland
| | - T. Pyhäjärvi
- Department of Biology; University of Oulu; PO Box 3000 FI-90014 Oulu Finland
| | - J. Aspi
- Department of Biology; University of Oulu; PO Box 3000 FI-90014 Oulu Finland
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