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Šimková A, Civáňová K, Gettová L, Gilles A. Genomic Porosity between Invasive Chondrostoma nasus and Endangered Endemic Parachondrostoma toxostoma (Cyprinidae): The Evolution of MHC IIB Genes. PLoS One 2013; 8:e65883. [PMID: 23824831 PMCID: PMC3688810 DOI: 10.1371/journal.pone.0065883] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 04/30/2013] [Indexed: 02/06/2023] Open
Abstract
Two cyprinid species, Parachondrostoma toxostoma, an endemic threatened species, and Chondrostoma nasus, an invasive species, live in sympatry in southern France and form two sympatric zones where the presence of intergeneric hybrids is reported. To estimate the potential threat to endemic species linked to the introduction of invasive species, we focused on the DAB genes (functional MHC IIB genes) because of their adaptive significance and role in parasite resistance. More specifically, we investigated (1) the variability of MHC IIB genes, (2) the selection pattern shaping MHC polymorphism, and (3) the extent to which trans-species evolution and intergeneric hybridization affect MHC polymorphism. In sympatric areas, the native species has more diversified MHC IIB genes when compared to the invasive species, probably resulting from the different origins and dispersal of both species. A similar level of MHC polymorphism was found at population level in both species, suggesting similar mechanisms generating MHC diversity. In contrast, a higher number of DAB-like alleles per specimen were found in invasive species. Invasive species tended to express the alleles of two DAB lineages, whilst native species tended to express the alleles of only the DAB3 lineage. Hybrids have a pattern of MHC expression intermediate between both species. Whilst positive selection acting on peptide binding sites (PBS) was demonstrated in both species, a slightly higher number of positively selected sites were identified in C. nasus, which could result from parasite-mediated selection. Bayesian clustering analysis revealed a similar pattern of structuring for the genetic variation when using microsatellites or the MHC approach. We confirmed the importance of trans-species evolution for MHC polymorphism. In addition, we demonstrated bidirectional gene flow for MHC IIB genes in sympatric areas. The positive significant correlation between MHC and microsatellites suggests that demographic factors may contribute to MHC variation on a short time scale.
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Affiliation(s)
- Andrea Šimková
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Kristína Civáňová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Lenka Gettová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - André Gilles
- Aix-Marseille Université, Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale, UMR Centre national de la recherche scientifique 7263, Evolution Génome Environnement, Marseille, France
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Karvonen A, Kristjánsson BK, Skúlason S, Lanki M, Rellstab C, Jokela J. Water temperature, not fish morph, determines parasite infections of sympatric Icelandic threespine sticklebacks (Gasterosteus aculeatus). Ecol Evol 2013; 3:1507-17. [PMID: 23789063 PMCID: PMC3686187 DOI: 10.1002/ece3.568] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 03/18/2013] [Accepted: 03/19/2013] [Indexed: 12/01/2022] Open
Abstract
Parasite communities of fishes are known to respond directly to the abiotic environment of the host, for example, to water quality and water temperature. Biotic factors are also important as they affect the exposure profile through heterogeneities in parasite distribution in the environment. Parasites in a particular environment may pose a strong selection on fish. For example, ecological differences in selection by parasites have been hypothesized to facilitate evolutionary differentiation of freshwater fish morphs specializing on different food types. However, as parasites may also respond directly to abiotic environment the parasite risk does not depend only on biotic features of the host environment. It is possible that different morphs experience specific selection gradients by parasites but it is not clear how consistent the selection is when abiotic factors change. We examined parasite pressure in sympatric morphs of threespine stickleback (Gasterosteus aculeatus) across a temperature gradient in two large Icelandic lakes, Myvatn and Thingvallavatn. Habitat-specific temperature gradients in these lakes are opposite. Myvatn lava rock morph lives in a warm environment, while the mud morph lives in the cold. In Thingvallavatn, the lava rock morph lives in a cold environment and the mud morph in a warm habitat. We found more parasites in fish living in higher temperature in both lakes, independent of the fish morph, and this pattern was similar for the two dominating parasite taxa, trematodes and cestodes. However, at the same time, we also found higher parasite abundance in a third morph living in deep cold-water habitat in Thingvallavatn compared to the cold-water lava morph, indicating strong effect of habitat-specific biotic factors. Our results suggest complex interactions between water temperature and biotic factors in determining the parasite community structure, a pattern that may have implications for differentiation of stickleback morphs.
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Affiliation(s)
- Anssi Karvonen
- Department of Biological and Environmental Science, University of JyväskyläP.O. Box 35, FI-40014, Jyväskylä, Finland
| | - Bjarni K Kristjánsson
- Department of Aquaculture and Fish Biology, Holar University CollegeIS-550, Saudarkrokur, Iceland
| | - Skúli Skúlason
- Department of Aquaculture and Fish Biology, Holar University CollegeIS-550, Saudarkrokur, Iceland
| | - Maiju Lanki
- Department of Biosciences, University of HelsinkiP.O.Box 65, FI-00014, Helsinki, Finland
| | - Christian Rellstab
- Department of Biological and Environmental Science, University of JyväskyläP.O. Box 35, FI-40014, Jyväskylä, Finland
- Swiss Federal Research Institute WSLZürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Jukka Jokela
- Eawag, Swiss Federal Institute of Aquatic Science and TechnologyP.O. Box 611, CH-8600, Dübendorf, Switzerland
- ETH Zürich, Institute of Integrative BiologyCH-8092, Zürich, Switzerland
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53
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Raeymaekers JAM, Hablützel PI, Grégoir AF, Bamps J, Roose AK, Vanhove MPM, Van Steenberge M, Pariselle A, Huyse T, Snoeks J, Volckaert FAM. Contrasting parasite communities among allopatric colour morphs of the Lake Tanganyika cichlid Tropheus. BMC Evol Biol 2013; 13:41. [PMID: 23409983 PMCID: PMC3599415 DOI: 10.1186/1471-2148-13-41] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 01/17/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Adaptation to different ecological environments is thought to drive ecological speciation. This phenomenon culminates in the radiations of cichlid fishes in the African Great Lakes. Multiple characteristic traits of cichlids, targeted by natural or sexual selection, are considered among the driving factors of these radiations. Parasites and pathogens have been suggested to initiate or accelerate speciation by triggering both natural and sexual selection. Three prerequisites for parasite-driven speciation can be inferred from ecological speciation theory. The first prerequisite is that different populations experience divergent infection levels. The second prerequisite is that these infection levels cause divergent selection and facilitate adaptive divergence. The third prerequisite is that parasite-driven adaptive divergence facilitates the evolution of reproductive isolation. Here we investigate the first and the second prerequisite in allopatric chromatically differentiated lineages of the rock-dwelling cichlid Tropheus spp. from southern Lake Tanganyika (Central Africa). Macroparasite communities were screened in eight populations belonging to five different colour morphs. RESULTS Parasite communities were mainly composed of acanthocephalans, nematodes, monogeneans, copepods, branchiurans, and digeneans. In two consecutive years (2011 and 2012), we observed significant variation across populations for infection with acanthocephalans, nematodes, monogeneans of the genera Gyrodactylus and Cichlidogyrus, and the copepod Ergasilus spp. Overall, parasite community composition differed significantly between populations of different colour morphs. Differences in parasite community composition were stable in time. The genetic structure of Tropheus populations was strong and showed a significant isolation-by-distance pattern, confirming that spatial isolation is limiting host dispersal. Correlations between parasite community composition and Tropheus genetic differentiation were not significant, suggesting that host dispersal does not influence parasite community diversification. CONCLUSIONS Subject to alternating episodes of isolation and secondary contact because of lake level fluctuations, Tropheus colour morphs are believed to accumulate and maintain genetic differentiation through a combination of vicariance, philopatric behaviour and mate discrimination. Provided that the observed contrasts in parasitism facilitate adaptive divergence among populations in allopatry (which is the current situation), and promote the evolution of reproductive isolation during episodes of sympatry, parasites might facilitate speciation in this genus.
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Affiliation(s)
- Joost A M Raeymaekers
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch, Deberiotstraat, 32, Leuven, B-3000, Belgium.
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54
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Daum JM, Davis LR, Bigler L, Woodhams DC. Hybrid advantage in skin peptide immune defenses of water frogs (Pelophylax esculentus) at risk from emerging pathogens. INFECTION GENETICS AND EVOLUTION 2012; 12:1854-64. [DOI: 10.1016/j.meegid.2012.07.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 07/30/2012] [Accepted: 07/31/2012] [Indexed: 02/08/2023]
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Bérénos C, Schmid-Hempel P, Wegner KM. Antagonistic Coevolution Accelerates the Evolution of Reproductive Isolation in Tribolium castaneum. Am Nat 2012; 180:520-8. [DOI: 10.1086/667589] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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56
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Natsopoulou ME, Pálsson S, Ólafsdóttir GÁ. Parasites and parallel divergence of the number of individual MHC alleles between sympatric three-spined stickleback Gasterosteus aculeatus morphs in Iceland. JOURNAL OF FISH BIOLOGY 2012; 81:1696-1714. [PMID: 23020569 DOI: 10.1111/j.1095-8649.2012.03430.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Two pairs of sympatric three-spined stickleback Gasterosteus aculeatus morphs and two single morph populations inhabiting mud and lava or rocky benthic habitats in four Icelandic lakes were screened for parasites and genotyped for MHC class IIB diversity. Parasitic infection differed consistently between G. aculeatus from different benthic habitats. Gasterosteus aculeatus from the lava or rocky habitats were more heavily infected in all lakes. A parallel pattern was also found in individual MHC allelic variation with lava G. aculeatus morphs exhibiting lower levels of variation than the mud morphs. Evidence for selective divergence in MHC allele number is ambiguous but supported by two findings in addition to the parallel pattern observed. MHC allele diversity was not consistent with diversity reported at neutral markers (microsatellites) and in Þingvallavatn the most common number of alleles in each morph was associated with lower infection levels. In the Þingvallavatn lava morph, lower infection levels by the two most common parasites, Schistocephalus solidus and Diplostomum baeri, were associated with different MHC allele numbers.
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Affiliation(s)
- M E Natsopoulou
- Research Centre of the Westfjords, University of Iceland, Adalstraeti 21, 415 Bolungarvík, Iceland
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57
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Lenz TL, Eizaguirre C, Rotter B, Kalbe M, Milinski M. Exploring local immunological adaptation of two stickleback ecotypes by experimental infection and transcriptome-wide digital gene expression analysis. Mol Ecol 2012; 22:774-86. [PMID: 22971109 PMCID: PMC3579235 DOI: 10.1111/j.1365-294x.2012.05756.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 07/10/2012] [Accepted: 07/15/2012] [Indexed: 11/28/2022]
Abstract
Understanding the extent of local adaptation in natural populations and the mechanisms that allow individuals to adapt to their native environment is a major avenue in molecular ecology research. Evidence for the frequent occurrence of diverging ecotypes in species that inhabit multiple ecological habitats is accumulating, but experimental approaches to understanding the biological pathways as well as the underlying genetic mechanisms are still rare. Parasites are invoked as one of the major selective forces driving evolution and are themselves dependent on the ecological conditions in a given habitat. Immunological adaptation to local parasite communities is therefore expected to be a key component of local adaptation in natural populations. Here, we use next-generation sequencing technology to compare the transcriptome-wide response of experimentally infected three-spined sticklebacks from a lake and a river population, which are known to evolve under selection by distinct parasite communities. By comparing overall gene expression levels as well as the activation of functional pathways in response to parasite exposure, we identified potential differences between the two stickleback populations at several levels. Our results suggest locally adapted patterns of gene regulation in response to parasite exposure, which may reflect different local optima in the trade-off between the benefits and the disadvantages of mounting an immune response because of quantitative differences of the local parasite communities.
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Affiliation(s)
- Tobias L Lenz
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany.
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58
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Reichard M, Spence R, Bryjová A, Bryja J, Smith C. Female rose bitterling prefer MHC-dissimilar males: experimental evidence. PLoS One 2012; 7:e40780. [PMID: 22815816 PMCID: PMC3399850 DOI: 10.1371/journal.pone.0040780] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 06/13/2012] [Indexed: 11/19/2022] Open
Abstract
The role of genetic benefits in female mate choice remains a controversial aspect of sexual selection theory. In contrast to "good allele" models of sexual selection, "compatible allele" models of mate choice predict that females prefer mates with alleles complementary to their own rather than conferring additive effects. While correlative results suggest complementary genetic effects to be plausible, direct experimental evidence is scarce. A previous study on the Chinese rose bitterling (Rhodeus ocellatus) demonstrated a positive correlation between female mate choice, offspring growth and survival, and the functional dissimilarity between the Major Histocompatibility Complex (MHC) alleles of males and females. Here we directly tested whether females used cues associated with MHC genes to select genetically compatible males in an experimental framework. By sequentially pairing females with MHC similar and dissimilar males, based on a priori known MHC profiles, we showed that females discriminated between similar and dissimilar males and deposited significantly more eggs with MHC dissimilar males. Notably, the degree of dissimilarity was an important factor for female decision to mate, possibly indicating a potential threshold value of dissimilarity for decision making, or of an indirect effect of the MHC.
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Affiliation(s)
- Martin Reichard
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czech Republic.
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59
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Feulner PGD, Chain FJJ, Panchal M, Eizaguirre C, Kalbe M, Lenz TL, Mundry M, Samonte IE, Stoll M, Milinski M, Reusch TBH, Bornberg-Bauer E. Genome-wide patterns of standing genetic variation in a marine population of three-spined sticklebacks. Mol Ecol 2012; 22:635-49. [PMID: 22747593 DOI: 10.1111/j.1365-294x.2012.05680.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Since the end of the Pleistocene, the three-spined stickleback (Gasterosteus aculeatus) has repeatedly colonized and adapted to various freshwater habitats probably originating from ancestral marine populations. Standing genetic variation and the underlying genomic architecture both have been speculated to contribute to recent adaptive radiations of sticklebacks. Here, we expand on the current genomic resources of this fish by providing extensive genome-wide variation data from six individuals from a marine (North Sea) stickleback population. Using next-generation sequencing and a combination of paired-end and mate-pair libraries, we detected a wide size range of genetic variation. Among the six individuals, we found more than 7% of the genome is polymorphic, consisting of 2599111 SNPs, 233464 indels and structural variation (SV) (>50 bp) such as 1054 copy-number variable regions (deletions and duplications) and 48 inversions. Many of these polymorphisms affect gene and coding sequences. Based on SNP diversity, we determined outlier regions concordant with signatures expected under adaptive evolution. As some of these outliers overlap with pronounced regions of copy-number variation, we propose the consideration of such SV when analysing SNP data from re-sequencing approaches. We further discuss the value of this resource on genome-wide variation for further investigation upon the relative contribution of standing variation on the parallel evolution of sticklebacks and the importance of the genomic architecture in adaptive radiation.
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Affiliation(s)
- Philine G D Feulner
- Institute for Evolution and Biodiversity, Evolutionary Bioinformatics, Westfaelische Wilhelms University, Muenster, Germany.
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60
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Karvonen A, Lundsgaard-Hansen B, Jokela J, Seehausen O. Differentiation in parasitism among ecotypes of whitefish segregating along depth gradients. OIKOS 2012. [DOI: 10.1111/j.1600-0706.2012.20555.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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61
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Sepil I, Moghadam HK, Huchard E, Sheldon BC. Characterization and 454 pyrosequencing of major histocompatibility complex class I genes in the great tit reveal complexity in a passerine system. BMC Evol Biol 2012; 12:68. [PMID: 22587557 PMCID: PMC3483247 DOI: 10.1186/1471-2148-12-68] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 05/03/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The critical role of Major Histocompatibility Complex (Mhc) genes in disease resistance and their highly polymorphic nature make them exceptional candidates for studies investigating genetic effects on survival, mate choice and conservation. Species that harbor many Mhc loci and high allelic diversity are particularly intriguing as they are potentially under strong selection and studies of such species provide valuable information as to the mechanisms maintaining Mhc diversity. However comprehensive genotyping of complex multilocus systems has been a major challenge to date with the result that little is known about the consequences of this complexity in terms of fitness effects and disease resistance. RESULTS In this study, we genotyped the Mhc class I exon 3 of the great tit (Parus major) from two nest-box breeding populations near Oxford, UK that have been monitored for decades. Characterization of Mhc class I exon 3 was adopted and bidirectional sequencing was carried using the 454 sequencing platform. Full analysis of sequences through a stepwise variant validation procedure allowed reliable typing of more than 800 great tits based on 214,357 reads; from duplicates we estimated the repeatability of typing as 0.94. A total of 862 alleles were detected, and the presence of at least 16 functional loci was shown - the highest number characterized in a wild bird species. Finally, the functional alleles were grouped into 17 supertypes based on their antigen binding affinities. CONCLUSIONS We found extreme complexity at the Mhc class I of the great tit both in terms of allelic diversity and gene number. The presence of many functional loci was shown, together with a pseudogene family and putatively non-functional alleles; there was clear evidence that functional alleles were under strong balancing selection. This study is the first step towards an in-depth analysis of this gene complex in this species, which will help understanding how parasite-mediated and sexual selection shape and maintain host genetic variation in nature. We believe that study systems like ours can make important contributions to the field of evolutionary biology and emphasize the necessity of integrating long-term field-based studies with detailed genetic analysis to unravel complex evolutionary processes.
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Affiliation(s)
- Irem Sepil
- Department of Zoology, Edward Grey Institute, University of Oxford, Oxford, OX1 3PS, UK.
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62
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Eizaguirre C, Lenz TL, Kalbe M, Milinski M. Divergent selection on locally adapted major histocompatibility complex immune genes experimentally proven in the field. Ecol Lett 2012; 15:723-31. [PMID: 22583762 PMCID: PMC3440595 DOI: 10.1111/j.1461-0248.2012.01791.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 12/12/2011] [Accepted: 04/02/2012] [Indexed: 11/26/2022]
Abstract
Although crucial for the understanding of adaptive evolution, genetically resolved examples of local adaptation are rare. To maximize survival and reproduction in their local environment, hosts should resist their local parasites and pathogens. The major histocompatibility complex (MHC) with its key function in parasite resistance represents an ideal candidate to investigate parasite-mediated local adaptation. Using replicated field mesocosms, stocked with second-generation lab-bred three-spined stickleback hybrids of a lake and a river population, we show local adaptation of MHC genotypes to population-specific parasites, independently of the genetic background. Increased allele divergence of lake MHC genotypes allows lake fish to fight the broad range of lake parasites, whereas more specific river genotypes confer selective advantages against the less diverse river parasites. Hybrids with local MHC genotype gained more body weight and thus higher fitness than those with foreign MHC in either habitat, suggesting the evolutionary significance of locally adapted MHC genotypes.
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Affiliation(s)
- Christophe Eizaguirre
- Department of Evolutionary Ecology of Marine Fishes, GEOMAR
- Helmholtz Center for Ocean Research, Kiel, 24105, Germany.
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63
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Wegner KM, Eizaguirre C. New(t)s and views from hybridizing MHC genes: introgression rather than trans-species polymorphism may shape allelic repertoires. Mol Ecol 2012; 21:779-81. [PMID: 22268859 DOI: 10.1111/j.1365-294x.2011.05401.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
One of the key features of major histocompatibility complex (MHC) genes is the frequent occurrence of trans-species polymorphism, that is 'the passage of allelic lineages from ancestral to descendant species' (Klein et al. 2007). Selectively maintained ancestral polymorphism may, however, be hard to distinguish from introgression of MHC alleles between hybridizing species (Fig. 1). In this issue of Molecular Ecology, Nadachowska-Brzyska et al. (2012) present data that suggest that the latter can be observed in two closely related species of newts, Lissotriton vulgaris (Lv) and L. montandoni (Lm) from south-east Europe. Strikingly, allelic MHC variation displayed more structure between geographically separated populations of L. vulgaris than across species in the hybrid zone. This suggests that high MHC variation in L. montadoni may result from mainly unidirectional gene flow between species, while differentiation between northern and southern populations of L. vulgaris might reflect local adaptation.
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Affiliation(s)
- K Mathias Wegner
- Leibniz Institute for Marine Sciences (IFM-Geomar), Evolutionary Ecology of Marine Fishes, Düsternbroker Weg 20, 24105 Kiel, Germany.
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The Role of Parasitism in Adaptive Radiations—When Might Parasites Promote and When Might They Constrain Ecological Speciation? INTERNATIONAL JOURNAL OF ECOLOGY 2012. [DOI: 10.1155/2012/280169] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Research on speciation and adaptive radiation has flourished during the past decades, yet factors underlying initiation of reproductive isolation often remain unknown. Parasites represent important selective agents and have received renewed attention in speciation research. We review the literature on parasite-mediated divergent selection in context of ecological speciation and present empirical evidence for three nonexclusive mechanisms by which parasites might facilitate speciation: reduced viability or fecundity of immigrants and hybrids, assortative mating as a pleiotropic by-product of host adaptation, and ecologically-based sexual selection. We emphasise the lack of research on speciation continuums, which is why no study has yet made a convincing case for parasite driven divergent evolution to initiate the emergence of reproductive isolation. We also point interest towards selection imposed by single versus multiple parasite species, conceptually linking this to strength and multifariousness of selection. Moreover, we discuss how parasites, by manipulating behaviour or impairing sensory abilities of hosts, may change the form of selection that underlies speciation. We conclude that future studies should consider host populations at variable stages of the speciation process, and explore recurrent patterns of parasitism and resistance that could pinpoint the role of parasites in imposing the divergent selection that initiates ecological speciation.
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65
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Affiliation(s)
- I Keller
- Department of Fish Ecology and Evolution, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Center of Ecology, Evolution and Biochemistry, Seestrasse 79, CH-6047 Kastanienbaum, Switzerland.
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66
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Divergent evolution of male aggressive behaviour: another reproductive isolation barrier in extremophile poeciliid fishes? INTERNATIONAL JOURNAL OF EVOLUTIONARY BIOLOGY 2011; 2012:148745. [PMID: 22315695 PMCID: PMC3270405 DOI: 10.1155/2012/148745] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 09/20/2011] [Accepted: 10/14/2011] [Indexed: 11/17/2022]
Abstract
Reproductive isolation among locally adapted populations may arise when immigrants from foreign habitats are selected against via natural or (inter-)sexual selection (female mate choice). We asked whether also intrasexual selection through male-male competition could promote reproductive isolation among populations of poeciliid fishes that are locally adapted to extreme environmental conditions [i.e., darkness in caves and/or toxic hydrogen sulphide (H(2)S)]. We found strongly reduced aggressiveness in extremophile P. oecilia mexicana, and darkness was the best predictor for the evolutionary reduction of aggressiveness, especially when combined with presence of H(2)S. We demonstrate that reduced aggression directly translates into migrant males being inferior when paired with males from non-sulphidic surface habitats. By contrast, the phylogenetically old sulphur endemic P. sulphuraria from another sulphide spring area showed no overall reduced aggressiveness, possibly indicating evolved mechanisms to better cope with H(2)S.
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67
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68
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Rudh A, Rogell B, Håstad O, Qvarnström A. Rapid population divergence linked with co-variation between coloration and sexual display in strawberry poison frogs. Evolution 2011; 65:1271-82. [PMID: 21166789 DOI: 10.1111/j.1558-5646.2010.01210.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The likelihood of speciation is assumed to increase when sexually selected traits diverge together with ecologically important traits. According to sexual selection theory, the evolution of exaggerated display behavior is driven by increased mating success, but limited by natural selection, for example, through predation. However, the evolution of aposematic coloration (i.e., an ecologically important trait) could relieve the evolution of exaggerated display behavior from the bound of predation, resulting in joint divergence in aposematic coloration and sexual display behavior between populations. We tested this idea by examining conspicuousness, using color contrasts between individuals and their native backgrounds, and sexual display of 118 males from genetically diverged populations of the Strawberry poison frog, Dendrobates pumilio. Our results show that the level of conspicuousness of the population predicts the sexual display behavior of males. Males from conspicuous populations used more exposed calling sites. We argue that changes in aposematic coloration may rapidly cause not only postmating isolation due to poorly adapted hybrids, but also premating isolation through shifts in mating behaviors.
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Affiliation(s)
- Andreas Rudh
- Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, Sweden.
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69
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Weissing FJ, Edelaar P, van Doorn GS. Adaptive speciation theory: a conceptual review. Behav Ecol Sociobiol 2011; 65:461-480. [PMID: 21423338 PMCID: PMC3038232 DOI: 10.1007/s00265-010-1125-7] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 11/17/2010] [Accepted: 11/22/2010] [Indexed: 11/10/2022]
Abstract
Speciation—the origin of new species—is the source of the diversity of life. A theory of speciation is essential to link poorly understood macro-evolutionary processes, such as the origin of biodiversity and adaptive radiation, to well understood micro-evolutionary processes, such as allele frequency change due to natural or sexual selection. An important question is whether, and to what extent, the process of speciation is ‘adaptive’, i.e., driven by natural and/or sexual selection. Here, we discuss two main modelling approaches in adaptive speciation theory. Ecological models of speciation focus on the evolution of ecological differentiation through divergent natural selection. These models can explain the stable coexistence of the resulting daughter species in the face of interspecific competition, but they are often vague about the evolution of reproductive isolation. Most sexual selection models of speciation focus on the diversification of mating strategies through divergent sexual selection. These models can explain the evolution of prezygotic reproductive isolation, but they are typically vague on questions like ecological coexistence. By means of an integrated model, incorporating both ecological interactions and sexual selection, we demonstrate that disruptive selection on both ecological and mating strategies is necessary, but not sufficient, for speciation to occur. To achieve speciation, mating must at least partly reflect ecological characteristics. The interaction of natural and sexual selection is also pivotal in a model where sexual selection facilitates ecological speciation even in the absence of diverging female preferences. In view of these results, it is counterproductive to consider ecological and sexual selection models as contrasting and incompatible views on speciation, one being dominant over the other. Instead, an integrative perspective is needed to achieve a thorough and coherent understanding of adaptive speciation.
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70
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Eizaguirre C, Lenz TL. Major histocompatibility complex polymorphism: dynamics and consequences of parasite-mediated local adaptation in fishes. JOURNAL OF FISH BIOLOGY 2010; 77:2023-2047. [PMID: 21133915 DOI: 10.1111/j.1095-8649.2010.02819.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Parasitism is a common form of life and represents a strong selective pressure for host organisms. In response to this evolutionary pressure, vertebrates have developed genetically coded defences such as the major histocompatibility complex (MHC). Mechanisms of parasite-mediated selection not only maintain outstanding polymorphism in these genes but have also been proposed to further promote host population divergence and ultimately speciation because it can drive evolution of local adaptation in which MHC genes play a crucial role. This review first highlights the dynamics and complexity of parasite-mediated selection in natural systems, which not only depends on dominating parasite strategies and on the taxonomic diversity of the parasite community but also includes the differences in parasite communities between habitats and niches, creating divergent selection on locally adapted populations. Then the different ways in which MHC genes potentially allow vertebrates to respond to these dynamics and to adapt locally are outlined. Finally, it is proposed that varying selection strength in time and space may lead to variation in the strength of precopulatory reproductive isolation which has evolved to maintain local adaptation.
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Affiliation(s)
- C Eizaguirre
- Leibniz Institute for Marine Sciences (IFM GEOMAR), Department of Evolutionary Ecology of Marine Fishes, Düsternbrooker Weg 20, 24105, Kiel, Germany.
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71
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Jeukens J, Renaut S, St-Cyr J, Nolte AW, Bernatchez L. The transcriptomics of sympatric dwarf and normal lake whitefish (Coregonus clupeaformis spp., Salmonidae) divergence as revealed by next-generation sequencing. Mol Ecol 2010; 19:5389-403. [PMID: 21087448 DOI: 10.1111/j.1365-294x.2010.04934.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Gene expression divergence is one of the mechanisms thought to be involved in the emergence of incipient species. Next-generation sequencing has become an extremely valuable tool for the study of this process by allowing whole transcriptome sequencing, or RNA-Seq. We have conducted a 454 GS-FLX pyrosequencing experiment to refine our understanding of adaptive divergence between dwarf and normal lake whitefish species (Coregonus clupeaformis spp.). The objectives were to: (i) investigate transcriptomic divergence as measured by liver RNA-Seq; (ii) test the correlation between divergence in expression and sequence polymorphism; and (iii) investigate the extent of allelic imbalance. We also compared the results of RNA-seq with those of a previous microarray study performed on the same fish. Following de novo assembly, results showed that normal whitefish overexpressed more contigs associated with protein synthesis while dwarf fish overexpressed more contigs related to energy metabolism, immunity and DNA replication and repair. Moreover, 63 SNPs showed significant allelic imbalance, and this phenomenon prevailed in the recently diverged dwarf whitefish. Results also showed an absence of correlation between gene expression divergence as measured by RNA-Seq and either polymorphism rate or sequence divergence between normal and dwarf whitefish. This study reiterates an important role for gene expression divergence, and provides evidence for allele-specific expression divergence as well as evolutionary decoupling of regulatory and coding sequences in the adaptive divergence of normal and dwarf whitefish. It also demonstrates how next-generation sequencing can lead to a more comprehensive understanding of transcriptomic divergence in a young species pair.
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Affiliation(s)
- Julie Jeukens
- Institut de Biologie Intégrative et des Systèmes (IBIS), Québec-Océan, Université Laval, Québec, QC, Canada.
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72
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Rice AM, Rudh A, Ellegren H, Qvarnström A. A guide to the genomics of ecological speciation in natural animal populations. Ecol Lett 2010; 14:9-18. [PMID: 21070555 DOI: 10.1111/j.1461-0248.2010.01546.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Interest in ecological speciation is growing, as evidence accumulates showing that natural selection can lead to rapid divergence between subpopulations. However, whether and how ecological divergence can lead to the buildup of reproductive isolation remains under debate. What is the relative importance of natural selection vs. neutral processes? How does adaptation generate reproductive isolation? Can ecological speciation occur despite homogenizing gene flow? These questions can be addressed using genomic approaches, and with the rapid development of genomic technology, will become more answerable in studies of wild populations than ever before. In this article, we identify open questions in ecological speciation theory and suggest useful genomic methods for addressing these questions in natural animal populations. We aim to provide a practical guide for ecologists interested in incorporating genomic methods into their research programs. An increased integration between ecological research and genomics has the potential to shed novel light on the origin of species.
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Affiliation(s)
- Amber M Rice
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
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73
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Edelaar P, van Eerde K. Non-random infection across individuals and populations supports that parasites can change morphology within an adaptive radiation. J Zool (1987) 2010. [DOI: 10.1111/j.1469-7998.2010.00755.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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74
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Eizaguirre C, Lenz TL, Sommerfeld RD, Harrod C, Kalbe M, Milinski M. Parasite diversity, patterns of MHC II variation and olfactory based mate choice in diverging three-spined stickleback ecotypes. Evol Ecol 2010. [DOI: 10.1007/s10682-010-9424-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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75
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Matthews B, Harmon LJ, M'Gonigle L, Marchinko KB, Schaschl H. Sympatric and allopatric divergence of MHC genes in threespine stickleback. PLoS One 2010; 5:e10948. [PMID: 20585386 PMCID: PMC2886830 DOI: 10.1371/journal.pone.0010948] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 04/30/2010] [Indexed: 11/19/2022] Open
Abstract
Parasites can strongly affect the evolution of their hosts, but their effects on host diversification are less clear. In theory, contrasting parasite communities in different foraging habitats could generate divergent selection on hosts and promote ecological speciation. Immune systems are costly to maintain, adaptable, and an important component of individual fitness. As a result, immune system genes, such as those of the Major Histocompatibility Complex (MHC), can change rapidly in response to parasite-mediated selection. In threespine stickleback (Gasterosteus aculeatus), as well as in other vertebrates, MHC genes have been linked with female mating preference, suggesting that divergent selection acting on MHC genes might influence speciation. Here, we examined genetic variation at MHC Class II loci of sticklebacks from two lakes with a limnetic and benthic species pair, and two lakes with a single species. In both lakes with species pairs, limnetics and benthics differed in their composition of MHC alleles, and limnetics had fewer MHC alleles per individual than benthics. Similar to the limnetics, the allopatric population with a pelagic phenotype had few MHC alleles per individual, suggesting a correlation between MHC genotype and foraging habitat. Using a simulation model we show that the diversity and composition of MHC alleles in a sympatric species pair depends on the amount of assortative mating and on the strength of parasite-mediated selection in adjacent foraging habitats. Our results indicate parallel divergence in the number of MHC alleles between sympatric stickleback species, possibly resulting from the contrasting parasite communities in littoral and pelagic habitats of lakes.
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Affiliation(s)
- Blake Matthews
- Aquatic Ecology Department, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Kastanienbaum, Switzerland.
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76
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Wolf JBW, Lindell J, Backström N. Speciation genetics: current status and evolving approaches. Philos Trans R Soc Lond B Biol Sci 2010; 365:1717-33. [PMID: 20439277 PMCID: PMC2871893 DOI: 10.1098/rstb.2010.0023] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The view of species as entities subjected to natural selection and amenable to change put forth by Charles Darwin and Alfred Wallace laid the conceptual foundation for understanding speciation. Initially marred by a rudimental understanding of hereditary principles, evolutionists gained appreciation of the mechanistic underpinnings of speciation following the merger of Mendelian genetic principles with Darwinian evolution. Only recently have we entered an era where deciphering the molecular basis of speciation is within reach. Much focus has been devoted to the genetic basis of intrinsic postzygotic isolation in model organisms and several hybrid incompatibility genes have been successfully identified. However, concomitant with the recent technological advancements in genome analysis and a newfound interest in the role of ecology in the differentiation process, speciation genetic research is becoming increasingly open to non-model organisms. This development will expand speciation research beyond the traditional boundaries and unveil the genetic basis of speciation from manifold perspectives and at various stages of the splitting process. This review aims at providing an extensive overview of speciation genetics. Starting from key historical developments and core concepts of speciation genetics, we focus much of our attention on evolving approaches and introduce promising methodological approaches for future research venues.
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Affiliation(s)
- Jochen B W Wolf
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden.
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77
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Galan M, Guivier E, Caraux G, Charbonnel N, Cosson JF. A 454 multiplex sequencing method for rapid and reliable genotyping of highly polymorphic genes in large-scale studies. BMC Genomics 2010; 11:296. [PMID: 20459828 PMCID: PMC2876125 DOI: 10.1186/1471-2164-11-296] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Accepted: 05/11/2010] [Indexed: 11/10/2022] Open
Abstract
Background High-throughput sequencing technologies offer new perspectives for biomedical, agronomical and evolutionary research. Promising progresses now concern the application of these technologies to large-scale studies of genetic variation. Such studies require the genotyping of high numbers of samples. This is theoretically possible using 454 pyrosequencing, which generates billions of base pairs of sequence data. However several challenges arise: first in the attribution of each read produced to its original sample, and second, in bioinformatic analyses to distinguish true from artifactual sequence variation. This pilot study proposes a new application for the 454 GS FLX platform, allowing the individual genotyping of thousands of samples in one run. A probabilistic model has been developed to demonstrate the reliability of this method. Results DNA amplicons from 1,710 rodent samples were individually barcoded using a combination of tags located in forward and reverse primers. Amplicons consisted in 222 bp fragments corresponding to DRB exon 2, a highly polymorphic gene in mammals. A total of 221,789 reads were obtained, of which 153,349 were finally assigned to original samples. Rules based on a probabilistic model and a four-step procedure, were developed to validate sequences and provide a confidence level for each genotype. The method gave promising results, with the genotyping of DRB exon 2 sequences for 1,407 samples from 24 different rodent species and the sequencing of 392 variants in one half of a 454 run. Using replicates, we estimated that the reproducibility of genotyping reached 95%. Conclusions This new approach is a promising alternative to classical methods involving electrophoresis-based techniques for variant separation and cloning-sequencing for sequence determination. The 454 system is less costly and time consuming and may enhance the reliability of genotypes obtained when high numbers of samples are studied. It opens up new perspectives for the study of evolutionary and functional genetics of highly polymorphic genes like major histocompatibility complex genes in vertebrates or loci regulating self-compatibility in plants. Important applications in biomedical research will include the detection of individual variation in disease susceptibility. Similarly, agronomy will benefit from this approach, through the study of genes implicated in productivity or disease susceptibility traits.
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Affiliation(s)
- Maxime Galan
- INRA EFPA, UMR CBGP (INRA/IRD/Cirad/Montpellier SupAgro), Campus international de Baillarguet, CS 30016, F-34988 Montferrier-sur-Lez cedex, France.
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78
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Bomblies K. Doomed lovers: mechanisms of isolation and incompatibility in plants. ANNUAL REVIEW OF PLANT BIOLOGY 2010; 61:109-124. [PMID: 20192733 DOI: 10.1146/annurev-arplant-042809-112146] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Adaptation to local conditions likely plays an important role in plant diversity and speciation. A fuller understanding of the role of adaptation in speciation requires connecting particular molecular events with selection occurring at individual, population, or community levels. Here I discuss five areas in which we understand the molecular basis of adaptation and isolation sufficiently to begin examining patterns. These examples highlight the importance of understanding both biotic and abiotic factors and the potential overlap between them, and demonstrate that understanding molecular mechanisms aids in interpreting pleiotropy and constraint. For example, mutations affecting anthocyanin production can affect both pollinator visitation and parasite attack, while edaphic adaptation can alter parasite susceptibility and reproductive timing. Adaptation is also implicated in postzygotic incompatibility: Potentially adaptive cytoplasmic divergence can lead to sterility or inviability; hybrid sterility genes may have pleiotropic effects in biotic or abiotic stress; and the plant immune system is implicated in hybrid failure.
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Affiliation(s)
- Kirsten Bomblies
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
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79
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Lenz TL, Eizaguirre C, Scharsack JP, Kalbe M, Milinski M. Disentangling the role of MHC-dependent 'good genes' and 'compatible genes' in mate-choice decisions of three-spined sticklebacks Gasterosteus aculeatus under semi-natural conditions. JOURNAL OF FISH BIOLOGY 2009; 75:2122-2142. [PMID: 20738677 DOI: 10.1111/j.1095-8649.2009.02410.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
To investigate and disentangle the role of major histocompatibility complex (MHC)-based 'good genes' and 'compatible genes' in mate choice, three-spined sticklebacks Gasterosteus aculeatus with specific MHC IIB genotypes were allowed to reproduce in an outdoor enclosure system. Here, fish were protected from predators but encountered their natural parasites. Mate choice for an intermediate genetic distance between parental MHC genotypes was observed, which would result in intermediate diversity in the offspring, but no mate choice based on good genes was found under the current semi-natural conditions. Investigation of immunological variables revealed that the less-specific innate immune system was more active in individuals with a genetically more divergent MHC allele repertoire. This suggests the need to compensate for an MHC-diminished T-cell repertoire and potentially explains the observed mate choice for intermediate MHC genetic distance. The present findings support a general pattern of mate choice for intermediate MHC diversity (i.e. compatible genes). In addition, the potentially dynamic role of MHC good genes in mate choice under different parasite pressures is discussed in the light of present and previous results.
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Affiliation(s)
- T L Lenz
- Max Planck Institute for Evolutionary Biology, Department of Evolutionary Ecology, August-Thienemann-Str. 2, 24306 Plön, Germany.
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80
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Fraser BA, Neff BD. Parasite mediated homogenizing selection at the MHC in guppies. Genetica 2009; 138:273-8. [PMID: 19728113 DOI: 10.1007/s10709-009-9402-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Accepted: 08/14/2009] [Indexed: 11/28/2022]
Abstract
Understanding the selective forces influencing genetic diversity is a fundamental goal of evolutionary ecology. The genes of the major histocompatibility complex (MHC) play a key role in the adaptive immune response of vertebrates and thus provide an excellent opportunity to examine the agents of selection on a functionally important gene. Here we examine the genetic architecture of the MHC class IIB genes in 10 wild populations of guppies (Poecilia reticulata) in Northern Trinidad. We have previously shown that these populations are significantly less diverged at the class IIB locus than expected based on neutral (microsatellite) loci. We now survey infection by Gyrodactylus turnbulli and G. bullatarudis, common parasitic worms that infect guppies, as a potential agent of homogenizing selection. We used a genetic algorithm to partition both additive and non-additive genetic effects of the five most common MHC allele types as well as a rare allele category. Although we found no evidence for non-additive effects, across the populations we found that one allele type (the a-type) had a significant negative additive effect on parasite load. Thus, individuals who had more copies of the a-type allele were infected with fewer gyrodactylus than individuals with fewer copies of the allele. These results not only link parasite infection with MHC genotype, they provide a mechanism of homogenizing selection across these otherwise disparate populations.
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Affiliation(s)
- Bonnie A Fraser
- Department of Biology, University of Western Ontario, London, Ontario, Canada.
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81
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Abstract
We develop a model for speciation due to postzygotic incompatibility generated by autoimmune reactions. The model is based on frequency-dependent interactions between host plants and their pathogens, which can generate disruptive selection and give rise to speciation if distant phenotypes become reproductively isolated. Based on recent experimental evidence from Arabidopsis, we assume that at the molecular level, incompatibility between host strains is caused by epistatic interactions between two proteins in the plant immune system--the guard and the guardee. Within each plant strain, immune reactions occur when the guardee protein is modified by a pathogen effector, and the guard subsequently binds to the guardee, thus precipitating an immune response. When guard and guardee proteins come from phenotypically distant parents, a hybrid's immune system can be triggered by erroneous interactions between these proteins even in the absence of pathogen attack, leading to severe autoimmune reactions in hybrids. This generates a Dobzhnasky-Muller incompatibility due to immune reactions. Our model shows how phenotypic variation generated by frequency-dependent host-pathogen interactions can lead to such postzygotic incompatibilities between extremal types, and hence to speciation.
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Affiliation(s)
- Iaroslav Ispolatov
- Department of Zoology, University of British Columbia, Vancouver, B.C., Canada
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82
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EIZAGUIRRE C, YEATES SE, LENZ TL, KALBE M, MILINSKI M. MHC-based mate choice combines good genes and maintenance of MHC polymorphism. Mol Ecol 2009; 18:3316-29. [DOI: 10.1111/j.1365-294x.2009.04243.x] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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