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Harkness A, Brandvain Y. Non-self recognition-based self-incompatibility can alternatively promote or prevent introgression. THE NEW PHYTOLOGIST 2021; 231:1630-1643. [PMID: 33533069 DOI: 10.1111/nph.17249] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 01/19/2021] [Indexed: 06/12/2023]
Abstract
Self-incompatibility alleles (S-alleles), which prevent self-fertilisation in plants, have historically been expected to benefit from negative frequency-dependent selection and invade when introduced to a new population through gene flow. However, the most taxonomically widespread form of self-incompatibility, the ribonuclease-based system ancestral to the core eudicots, functions through collaborative non-self recognition, which can affect both short-term patterns of gene flow and the long-term process of S-allele diversification. We analysed a model of S-allele evolution in two populations connected by migration, focussing on comparisons among the fates of S-alleles initially unique to each population and those shared among populations. We found that both shared and unique S-alleles from the population with more unique S-alleles were usually fitter compared with S-alleles from the population with fewer S-alleles. Resident S-alleles often became extinct and were replaced by migrant S-alleles, although this outcome could be averted by pollen limitation or biased migration. Collaborative non-self recognition will usually either result in the whole-sale replacement of S-alleles from one population with those from another or else disfavour introgression of S-alleles altogether.
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Affiliation(s)
- Alexander Harkness
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St Paul, MN, 55108, USA
| | - Yaniv Brandvain
- Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, 55108, USA
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Durand E, Chantreau M, Le Veve A, Stetsenko R, Dubin M, Genete M, Llaurens V, Poux C, Roux C, Billiard S, Vekemans X, Castric V. Evolution of self-incompatibility in the Brassicaceae: Lessons from a textbook example of natural selection. Evol Appl 2020; 13:1279-1297. [PMID: 32684959 PMCID: PMC7359833 DOI: 10.1111/eva.12933] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/25/2020] [Accepted: 01/29/2020] [Indexed: 12/14/2022] Open
Abstract
Self-incompatibility (SI) is a self-recognition genetic system enforcing outcrossing in hermaphroditic flowering plants and results in one of the arguably best understood forms of natural (balancing) selection maintaining genetic variation over long evolutionary times. A rich theoretical and empirical population genetics literature has considerably clarified how the distribution of SI phenotypes translates into fitness differences among individuals by a combination of inbreeding avoidance and rare-allele advantage. At the same time, the molecular mechanisms by which self-pollen is specifically recognized and rejected have been described in exquisite details in several model organisms, such that the genotype-to-phenotype map is also pretty well understood, notably in the Brassicaceae. Here, we review recent advances in these two fronts and illustrate how the joint availability of detailed characterization of genotype-to-phenotype and phenotype-to-fitness maps on a single genetic system (plant self-incompatibility) provides the opportunity to understand the evolutionary process in a unique perspective, bringing novel insight on general questions about the emergence, maintenance, and diversification of a complex genetic system.
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Affiliation(s)
| | | | - Audrey Le Veve
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | | | - Manu Dubin
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | - Mathieu Genete
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | - Violaine Llaurens
- Institut de Systématique, Evolution et Biodiversité (ISYEB)Muséum national d'Histoire naturelleCNRS, Sorbonne Université, EPHE, Université des Antilles CP 5057 rue Cuvier, 75005 ParisFrance
| | - Céline Poux
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | - Camille Roux
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
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Mable BK, Brysting AK, Jørgensen MH, Carbonell AKZ, Kiefer C, Ruiz-Duarte P, Lagesen K, Koch MA. Adding Complexity to Complexity: Gene Family Evolution in Polyploids. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00114] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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Becheler R, Masson JP, Arnaud-Haond S, Halkett F, Mariette S, Guillemin ML, Valero M, Destombe C, Stoeckel S. ClonEstiMate, a Bayesian method for quantifying rates of clonality of populations genotyped at two-time steps. Mol Ecol Resour 2017; 17:e251-e267. [DOI: 10.1111/1755-0998.12698] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Ronan Becheler
- Evolutionary Biology and Ecology of Algae; CNRS; Sorbonne Universités; UPMC; University of Paris VI; UC; UACH; UMI 3614; Roscoff France
| | - Jean-Pierre Masson
- Institute for Genetics; Environment and Plant Protection; INRA; UMR1349; Le Rheu France
| | - Sophie Arnaud-Haond
- Ifremer; MARBEC (Marine Biodiversity, Exploitation and Conservation); Boulevard Jean Monet; 34200 SETE
| | | | | | - Marie-Laure Guillemin
- Evolutionary Biology and Ecology of Algae; CNRS; Sorbonne Universités; UPMC; University of Paris VI; UC; UACH; UMI 3614; Roscoff France
- Facultad de Ciencias; Instituto de Ciencias Ambientales y Evolutivas; Universidad Austral de Chile; Valdivia Chile
| | - Myriam Valero
- Evolutionary Biology and Ecology of Algae; CNRS; Sorbonne Universités; UPMC; University of Paris VI; UC; UACH; UMI 3614; Roscoff France
| | - Christophe Destombe
- Evolutionary Biology and Ecology of Algae; CNRS; Sorbonne Universités; UPMC; University of Paris VI; UC; UACH; UMI 3614; Roscoff France
| | - Solenn Stoeckel
- Institute for Genetics; Environment and Plant Protection; INRA; UMR1349; Le Rheu France
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Llaurens V, Whibley A, Joron M. Genetic architecture and balancing selection: the life and death of differentiated variants. Mol Ecol 2017; 26:2430-2448. [PMID: 28173627 DOI: 10.1111/mec.14051] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 12/15/2016] [Accepted: 12/19/2016] [Indexed: 01/02/2023]
Abstract
Balancing selection describes any form of natural selection, which results in the persistence of multiple variants of a trait at intermediate frequencies within populations. By offering up a snapshot of multiple co-occurring functional variants and their interactions, systems under balancing selection can reveal the evolutionary mechanisms favouring the emergence and persistence of adaptive variation in natural populations. We here focus on the mechanisms by which several functional variants for a given trait can arise, a process typically requiring multiple epistatic mutations. We highlight how balancing selection can favour specific features in the genetic architecture and review the evolutionary and molecular mechanisms shaping this architecture. First, balancing selection affects the number of loci underlying differentiated traits and their respective effects. Control by one or few loci favours the persistence of differentiated functional variants by limiting intergenic recombination, or its impact, and may sometimes lead to the evolution of supergenes. Chromosomal rearrangements, particularly inversions, preventing adaptive combinations from being dissociated are increasingly being noted as features of such systems. Similarly, due to the frequency of heterozygotes maintained by balancing selection, dominance may be a key property of adaptive variants. High heterozygosity and limited recombination also influence associated genetic load, as linked recessive deleterious mutations may be sheltered. The capture of deleterious elements in a locus under balancing selection may reinforce polymorphism by further promoting heterozygotes. Finally, according to recent genomewide scans, balanced polymorphism might be more pervasive than generally thought. We stress the need for both functional and ecological studies to characterize the evolutionary mechanisms operating in these systems.
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Affiliation(s)
- Violaine Llaurens
- Institut de Systématique Evolution et Biodiversité (UMR 7205 CNRS, MNHN, UPMC, EPHE), Muséum National d'Histoire Naturelle - CP50, 45 rue Buffon, 75005, Paris, France
| | - Annabel Whibley
- Cell and Developmental Biology, John Innes Centre, Norwich, Norfolk, NR4 7UH, UK
| | - Mathieu Joron
- Centre d'Ecologie Fonctionnelle et Evolutive (UMR 5175 CNRS, Université de Montpellier, Université Paul Valéry Montpellier, EPHE), 1919 route de Mende, 34293, Montpellier, France
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Nantongo JS, Eilu G, Geburek T, Schueler S, Konrad H. Detection of Self Incompatibility Genotypes in Prunus africana: Characterization, Evolution and Spatial Analysis. PLoS One 2016; 11:e0155638. [PMID: 27348423 PMCID: PMC4922633 DOI: 10.1371/journal.pone.0155638] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 05/02/2016] [Indexed: 11/29/2022] Open
Abstract
In flowering plants, self-incompatibility is an effective genetic mechanism that prevents self-fertilization. Most Prunus tree species exhibit a homomorphic gametophytic self-incompatibility (GSI) system, in which the pollen phenotype is encoded by its own haploid genome. To date, no identification of S-alleles had been done in Prunus africana, the only member of the genus in Africa. To identify S-RNase alleles and hence determine S-genotypes in African cherry (Prunus africana) from Mabira Forest Reserve, Uganda, primers flanking the first and second intron were designed and these amplified two bands in most individuals. PCR bands on agarose indicated 26 and 8 different S-alleles for second and first intron respectively. Partial or full sequences were obtained for all these fragments. Comparison with published S-RNase data indicated that the amplified products were S-RNase alleles with very high interspecies homology despite the high intraspecific variation. Against expectations for a locus under balancing selection, frequency and spatial distribution of the alleles in a study plot was not random. Implications of the results to breeding efforts in the species are discussed, and mating experiments are strongly suggested to finally prove the functionality of SI in P. africana.
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Affiliation(s)
| | | | - Thomas Geburek
- Austrian Federal Office and Research Centre for Forests (BFW), Vienna, Austria
| | - Silvio Schueler
- Austrian Federal Office and Research Centre for Forests (BFW), Vienna, Austria
| | - Heino Konrad
- Austrian Federal Office and Research Centre for Forests (BFW), Vienna, Austria
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Hedhly A, Wünsch A, Kartal Ö, Herrero M, Hormaza JI. Paternal-specific S-allele transmission in sweet cherry (Prunus avium L.): the potential for sexual selection. J Evol Biol 2016; 29:490-501. [PMID: 26559165 DOI: 10.1111/jeb.12790] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 10/30/2015] [Accepted: 11/03/2015] [Indexed: 11/27/2022]
Abstract
Homomorphic self-incompatibility is a well-studied example of a physiological process that is thought to increase population diversity and reduce the expression of inbreeding depression. Whereas theoretical models predict the presence of a large number of S-haplotypes with equal frequencies at equilibrium, unequal allele frequencies have been repeatedly reported and attributed to sampling effects, population structure, demographic perturbation, sheltered deleterious mutations or selection pressure on linked genes. However, it is unclear to what extent unequal segregations are the results of gametophytic or sexual selection. Although these two forces are difficult to disentangle, testing S-alleles in the offspring of controlled crosses provides an opportunity to separate these two phenomena. In this work, segregation and transmission of S-alleles have been characterized in progenies of mixed donors and fully compatible pollinations under field conditions in Prunus avium. Seed set patterns and pollen performance have also been characterized. The results reveal paternal-specific distorted transmission of S-alleles in most of the crosses. Interestingly, S-allele segregation within any given paternal or maternal S-locus was random. Observations on pollen germination, pollen tube growth rate, pollen tube cohort size, seed set dynamics and transmission patterns strongly suggest post-pollination, prezygotic sexual selection, with male-male competition as the most likely mechanism. According to these results, post-pollination sexual selection takes precedence over frequency-dependent selection in explaining unequal S-haplotype frequencies.
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Affiliation(s)
- A Hedhly
- Institute of Plant Biology, University of Zurich, Zurich, Switzerland
| | - A Wünsch
- Centro de Investigación y Tecnología Agroalimentaria (CITA), Instituto Agroalimentario de Aragón - IA2 (CITA-Universidad de Zaragoza), Zaragoza, Spain
| | - Ö Kartal
- Institute of Plant Biology, University of Zurich, Zurich, Switzerland
| | - M Herrero
- Estación Experimental de Aula Dei, CSIC, Zaragoza, Spain
| | - J I Hormaza
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSM La Mayora - CSIC - UMA), Algarrobo-Costa, Málaga, Spain
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8
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Brennan AC, Harris SA, Hiscock SJ. The population genetics of sporophytic self-incompatibility in three hybridizing senecio (asteraceae) species with contrasting population histories. Evolution 2013; 67:1347-67. [PMID: 23617913 DOI: 10.1111/evo.12033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 11/28/2012] [Indexed: 11/30/2022]
Abstract
Hybridization generates evolutionary novelty and spreads adaptive variation. By promoting outcrossing, plant self-incompatibility (SI) systems also favor interspecific hybridization because the S locus is under strong negative frequency-dependent balancing selection. This study investigates the SI mating systems of three hybridizing Senecio species with contrasting population histories. Senecio aethnensis and S. chrysanthemifolius native to Sicily, form a hybrid zone at intermediate altitudes on Mount Etna, and their neo-homoploid hybrid species, S. squalidus, has colonized disturbed urban habitats in the UK during the last 150 years. We show that all three species express sporophytic SI (SSI), where pollen incompatibility is controlled by the diploid parental genome, and that SSI is inherited and functions normally in hybrids. Large-scale crossing studies of wild sampled populations allowed direct comparison of SSI between species and found that the main impacts of colonization in S. squalidus compared to Sicilian Senecio was a reduced number of S alleles, increased S allele frequencies, and increased interpopulation S allele sharing. In general, many S alleles were shared between species and the S locus showed reduced intra- and interspecific population genetic structure compared to molecular genetic markers, indicative of enhanced effective gene flow due to balancing selection.
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Affiliation(s)
- Adrian C Brennan
- Estación Biológica de Doñana (EBD-CSIC), Avenida Américo Vespucio s/n, 41092 Sevilla, Spain
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Shuri K, Saika K, Junko K, Michiharu K, Nagamitsu T, Iwata H, Tsumura Y, Mukai Y. Impact of negative frequency-dependent selection on mating pattern and genetic structure: a comparative analysis of the S-locus and nuclear SSR loci in Prunus lannesiana var. speciosa. Heredity (Edinb) 2012; 109:188-98. [PMID: 22669074 DOI: 10.1038/hdy.2012.29] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Mating processes of local demes and spatial genetic structure of island populations at the self-incompatibility (S-) locus under negative frequency-dependent selection (NFDS) were evaluated in Prunus lannesiana var. speciosa in comparison with nuclear simple sequence repeat (SSR) loci that seemed to be evolutionarily neutral. Our observations of local mating patterns indicated that male-female pair fecundity was influenced by not only self-incompatibility, but also various factors, such as kinship, pollen production and flowering synchrony. In spite of the mating bias caused by these factors, the NFDS effect on changes in allele frequencies from potential mates to mating pollen was detected at the S-locus but not at the SSR loci, although the changes from adult to juvenile cohorts were not apparent at any loci. Genetic differentiation and isolation-by-distance over various spatial scales were smaller at the S-locus than at the SSR loci, as expected under the NFDS. Allele-sharing distributions among the populations also had a unimodal pattern at the S-locus, indicating the NFDS effect except for alleles unique to individual populations probably due to isolation among islands, although this pattern was not exhibited by the SSR loci. Our results suggest that the NFDS at the S-locus has an impact on both the mating patterns and the genetic structure in the P. lannesiana populations studied.
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Affiliation(s)
- K Shuri
- Department of Forest Genetics, Forestry and Forest Products Research Institute, Tsukuba, Japan.
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Stoeckel S, Klein EK, Oddou-Muratorio S, Musch B, Mariette S. Microevolution of S-allele frequencies in wild cherry populations: respective impacts of negative frequency dependent selection and genetic drift. Evolution 2011; 66:486-504. [PMID: 22276543 DOI: 10.1111/j.1558-5646.2011.01457.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Negative frequency dependent selection (NFDS) is supposed to be the main force controlling allele evolution at the gametophytic self-incompatibility locus (S-locus) in strictly outcrossing species. Genetic drift also influences S-allele evolution. In perennial sessile organisms, evolution of allelic frequencies over two generations is mainly shaped by individual fecundities and spatial processes. Using wild cherry populations between two successive generations, we tested whether S-alleles evolved following NFDS qualitative and quantitative predictions. We showed that allelic variation was negatively correlated with parental allelic frequency as expected under NFDS. However, NFDS predictions in finite population failed to predict more than half S-allele quantitative evolution. We developed a spatially explicit mating model that included the S-locus. We studied the effects of self-incompatibility and local drift within populations due to pollen dispersal in spatially distributed individuals, and variation in male fecundity on male mating success and allelic frequency evolution. Male mating success was negatively related to male allelic frequency as expected under NFDS. Spatial genetic structure combined with self-incompatibility resulted in higher effective pollen dispersal. Limited pollen dispersal in structured distributions of individuals and genotypes and unequal pollen production significantly contributed to S-allele frequency evolution by creating local drift effects strong enough to counteract the NFDS effect on some alleles.
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Affiliation(s)
- Solenn Stoeckel
- Cemagref, Unité de Recherches Ecosystèmes Forestiers, Domaine des Barres, 45290 Nogent-sur-Vernisson, France.
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Does life in unstable environments favour facultative selfing? A case study in the freshwater snail Drepanotrema depressissimum (Basommatophora: Planorbidae). Evol Ecol 2011. [DOI: 10.1007/s10682-011-9520-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Mariette S, Tavaud M, Arunyawat U, Capdeville G, Millan M, Salin F. Population structure and genetic bottleneck in sweet cherry estimated with SSRs and the gametophytic self-incompatibility locus. BMC Genet 2010; 11:77. [PMID: 20727153 PMCID: PMC2933703 DOI: 10.1186/1471-2156-11-77] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 08/20/2010] [Indexed: 11/21/2022] Open
Abstract
Background Domestication and breeding involve the selection of particular phenotypes, limiting the genomic diversity of the population and creating a bottleneck. These effects can be precisely estimated when the location of domestication is established. Few analyses have focused on understanding the genetic consequences of domestication and breeding in fruit trees. In this study, we aimed to analyse genetic structure and changes in the diversity in sweet cherry Prunus avium L. Results Three subgroups were detected in sweet cherry, with one group of landraces genetically very close to the analysed wild cherry population. A limited number of SSR markers displayed deviations from the frequencies expected under neutrality. After the removal of these markers from the analysis, a very limited bottleneck was detected between wild cherries and sweet cherry landraces, with a much more pronounced bottleneck between sweet cherry landraces and modern sweet cherry varieties. The loss of diversity between wild cherries and sweet cherry landraces at the S-locus was more significant than that for microsatellites. Particularly high levels of differentiation were observed for some S-alleles. Conclusions Several domestication events may have happened in sweet cherry or/and intense gene flow from local wild cherry was probably maintained along the evolutionary history of the species. A marked bottleneck due to breeding was detected, with all markers, in the modern sweet cherry gene pool. The microsatellites did not detect the bottleneck due to domestication in the analysed sample. The vegetative propagation specific to some fruit trees may account for the differences in diversity observed at the S-locus. Our study provides insights into domestication events of cherry, however, requires confirmation on a larger sampling scheme for both sweet cherry landraces and wild cherry.
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Affiliation(s)
- Stéphanie Mariette
- INRA, Unité de Recherche sur les Espèces Fruitières, Domaine de la Grande Ferrade, 71 avenue Edouard Bourlaux, BP 81, 33883 Villenave d'Ornon Cedex, France.
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Effect of balancing selection on spatial genetic structure within populations: theoretical investigations on the self-incompatibility locus and empirical studies in Arabidopsis halleri. Heredity (Edinb) 2010; 106:319-29. [PMID: 20531450 DOI: 10.1038/hdy.2010.68] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The effect of selection on patterns of genetic structure within and between populations may be studied by contrasting observed patterns at the genes targeted by selection with those of unlinked neutral marker loci. Local directional selection on target genes will produce stronger population genetic structure than at neutral loci, whereas the reverse is expected for balancing selection. However, theoretical predictions on the intensity of this signal under precise models of balancing selection are still lacking. Using negative frequency-dependent selection acting on self-incompatibility systems in plants as a model of balancing selection, we investigated the effect of such selection on patterns of spatial genetic structure within a continuous population. Using numerical simulations, we tested the effect of the type of self-incompatibility system, the number of alleles at the self-incompatibility locus and the dominance interactions among them, the extent of gene dispersal, and the immigration rate on spatial genetic structure at the selected locus and at unlinked neutral loci. We confirm that frequency-dependent selection is expected to reduce the extent of spatial genetic structure as compared to neutral loci, particularly in situations with low number of alleles at the self-incompatibility locus, high frequency of codominant interactions among alleles, restricted gene dispersal and restricted immigration from outside populations. Hence the signature of selection on spatial genetic structure is expected to vary across species and populations, and we show that empirical data from the literature as well as data reported here on three natural populations of the herb Arabidopsis halleri confirm these theoretical results.
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Busch JW, Joly S, Schoen DJ. DOES MATE LIMITATION IN SELF-INCOMPATIBLE SPECIES PROMOTE THE EVOLUTION OF SELFING? THE CASE OF LEAVENWORTHIA ALABAMICA. Evolution 2009; 64:1657-70. [DOI: 10.1111/j.1558-5646.2009.00925.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Holderegger R, Häner R, Csencsics D, Angelone S, Hoebee SE. S-ALLELE DIVERSITY SUGGESTS NO MATE LIMITATION IN SMALL POPULATIONS OF A SELF-INCOMPATIBLE PLANT. Evolution 2008; 62:2922-8. [PMID: 18752611 DOI: 10.1111/j.1558-5646.2008.00498.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Rolf Holderegger
- WSL Swiss Federal Research Institute, CH-8903 Birmensdorf, Switzerland.
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16
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Llaurens V, Billiard S, Leducq JB, Castric V, Klein EK, Vekemans X. DOES FREQUENCY-DEPENDENT SELECTION WITH COMPLEX DOMINANCE INTERACTIONS ACCURATELY PREDICT ALLELIC FREQUENCIES AT THE SELF-INCOMPATIBILITY LOCUS INARABIDOPSIS HALLERI? Evolution 2008; 62:2545-57. [DOI: 10.1111/j.1558-5646.2008.00469.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
In Prunus, the self-incompatibility (S-) locus region is <70 kb. Two genes--the S-RNase, which encodes the functional female recognition component, and the SFB gene, which encodes the pollen recognition component--must co-evolve as a genetic unit to maintain functional incompatibility. Therefore, recombination must be severely repressed at the S-locus. Levels of recombination at genes in the vicinity of the S-locus have not yet been rigorously tested; thus it is unknown whether recombination is also severely repressed at these loci. In this work, we looked at variability levels and patterns at the Prunus spinosa SLFL1 gene, which is physically close to the S-RNase gene. Our results suggest that the recombination level increases near the SLFL1 coding region. These findings are discussed in the context of theoretical models predicting an effect of linked weakly deleterious mutations on the relatedness of S-locus specificities. Moreover, we show that SLFL1 belongs to a gene family of at least five functional genes and that SLFL1 pseudogenes are frequently found in the S-locus region.
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Vieira J, Santos RAM, Ferreira SM, Vieira CP. Inferences on the number and frequency of S-pollen gene (SFB) specificities in the polyploid Prunus spinosa. Heredity (Edinb) 2008; 101:351-8. [PMID: 18594559 DOI: 10.1038/hdy.2008.60] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In flowering plants, self-incompatibility is a genetic mechanism that prevents self-fertilization. In gametophytic self-incompatibility (GSI), pollen specificity is encoded by the haploid genotype of the pollen tube. In GSI, specificities are maintained by frequency-dependent selection, and for diploid species, at equilibrium, equal specificity frequencies (isoplethy) are expected. This prediction has been tested in diploid, but never in polyploid self-incompatible species. For the latter, there is no theoretical expectation regarding isoplethy. Here, we report the first empirical study on specificity frequencies in a natural population of a polyploid self-incompatible species, Prunus spinosa. A total of 32 SFB (the pollen S gene) putative specificities are observed in a large sample from a natural population. Although P. spinosa is polyploid, the number of specificities found is similar to that reported for other diploid Rosaceae species. Unequal specificity frequencies are observed.
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Affiliation(s)
- J Vieira
- 1Molecular Evolution Group, Instituto de Biologia Molecular e Celular, University of Porto, Porto, Portugal
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