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Hughes PW, Simons AM. Microsatellite evidence for obligate autogamy, but abundant genetic variation in the herbaceous monocarp Lobelia inflata (Campanulaceae). J Evol Biol 2015; 28:2068-77. [PMID: 26300530 DOI: 10.1111/jeb.12734] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 08/09/2015] [Accepted: 08/17/2015] [Indexed: 11/29/2022]
Abstract
Although high levels of self-fertilization (>85%) are not uncommon in nature, organisms reproducing entirely through selfing are extremely rare. Predominant selfers are expected to have low genetic diversity because genetic variation is distributed among rather than within lineages and is readily lost through genetic drift. We examined genetic diversity at 22 microsatellite loci in 105 individuals from a population of the semelparous herb Lobelia inflata L. and found (i) no evidence of heterozygosity through outcrossing, yet (ii) high rates of genetic polymorphism (2-4 alleles per locus). Furthermore, this genetic variation among lineages was associated with phenotypic traits (e.g. flower colour, size at first flower). Coupled with previous work characterizing the fitness consequences of reproductive timing, our results suggest that temporal genotype-by-environment interaction may maintain genetic variation and, because genetic variation occurs only among lineages, this simple system offers a unique opportunity for future tests of this mechanism.
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Affiliation(s)
- P W Hughes
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - A M Simons
- Department of Biology, Carleton University, Ottawa, ON, Canada
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102
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Sinn BT, Kelly LM, Freudenstein JV. Putative floral brood-site mimicry, loss of autonomous selfing, and reduced vegetative growth are significantly correlated with increased diversification in Asarum (Aristolochiaceae). Mol Phylogenet Evol 2015; 89:194-204. [DOI: 10.1016/j.ympev.2015.04.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 04/20/2015] [Accepted: 04/21/2015] [Indexed: 11/26/2022]
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103
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Abstract
A synopsis is provided of different expressions of whole-animal vertebrate clonality (asexual organismal-level reproduction), both in the laboratory and in nature. For vertebrate taxa, such clonal phenomena include the following: human-mediated cloning via artificial nuclear transfer; intergenerational clonality in nature via parthenogenesis and gynogenesis; intergenerational hemiclonality via hybridogenesis and kleptogenesis; intragenerational clonality via polyembryony; and what in effect qualifies as clonal replication via self-fertilization and intense inbreeding by simultaneous hermaphrodites. Each of these clonal or quasi-clonal mechanisms is described, and its evolutionary genetic ramifications are addressed. By affording an atypical vantage on standard vertebrate reproduction, clonality offers fresh perspectives on the evolutionary and ecological significance of recombination-derived genetic variety.
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Affiliation(s)
- John C Avise
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697
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104
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105
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Aguiar B, Vieira J, Cunha AE, Fonseca NA, Iezzoni A, van Nocker S, Vieira CP. Convergent evolution at the gametophytic self-incompatibility system in Malus and Prunus. PLoS One 2015; 10:e0126138. [PMID: 25993016 PMCID: PMC4438004 DOI: 10.1371/journal.pone.0126138] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 03/30/2015] [Indexed: 12/24/2022] Open
Abstract
S-RNase-based gametophytic self-incompatibility (GSI) has evolved once before the split of the Asteridae and Rosidae. This conclusion is based on the phylogenetic history of the S-RNase that determines pistil specificity. In Rosaceae, molecular characterizations of Prunus species, and species from the tribe Pyreae (i.e., Malus, Pyrus, Sorbus) revealed different numbers of genes determining S-pollen specificity. In Prunus only one pistil and pollen gene determine GSI, while in Pyreae there is one pistil but multiple pollen genes, implying different specificity recognition mechanisms. It is thus conceivable that within Rosaceae the genes involved in GSI in the two lineages are not orthologous but possibly paralogous. To address this hypothesis we characterised the S-RNase lineage and S-pollen lineage genes present in the genomes of five Rosaceae species from three genera: M. × domestica (apple, self-incompatible (SI); tribe Pyreae), P. persica (peach, self-compatible (SC); Amygdaleae), P. mume (mei, SI; Amygdaleae), Fragaria vesca (strawberry, SC; Potentilleae), and F. nipponica (mori-ichigo, SI; Potentilleae). Phylogenetic analyses revealed that the Malus and Prunus S-RNase and S-pollen genes belong to distinct gene lineages, and that only Prunus S-RNase and SFB-lineage genes are present in Fragaria. Thus, S-RNase based GSI system of Malus evolved independently from the ancestral system of Rosaceae. Using expression patterns based on RNA-seq data, the ancestral S-RNase lineage gene is inferred to be expressed in pistils only, while the ancestral S-pollen lineage gene is inferred to be expressed in tissues other than pollen.
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Affiliation(s)
- Bruno Aguiar
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Jorge Vieira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Ana E. Cunha
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Nuno A. Fonseca
- CRACS-INESC Porto, Rua do Campo Alegre 1021/1055, 4169–007, Porto, Portugal
- European Bioinformatics Institute (EMBL-EBI), Welcome Trust Genome Campus, CB10 1SD, Cambridge, United Kingdom
| | - Amy Iezzoni
- Michigan State University, East Lansing, Michigan, United States of America
| | - Steve van Nocker
- Michigan State University, East Lansing, Michigan, United States of America
| | - Cristina P. Vieira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- * E-mail:
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106
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Grossenbacher D, Briscoe Runquist R, Goldberg EE, Brandvain Y. Geographic range size is predicted by plant mating system. Ecol Lett 2015; 18:706-13. [PMID: 25980327 DOI: 10.1111/ele.12449] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 02/13/2015] [Accepted: 04/09/2015] [Indexed: 11/30/2022]
Abstract
Species' geographic ranges vary enormously, and even closest relatives may differ in range size by several orders of magnitude. With data from hundreds of species spanning 20 genera in 15 families, we show that plant species that autonomously reproduce via self-pollination consistently have larger geographic ranges than their close relatives that generally require two parents for reproduction. Further analyses strongly implicate autonomous self-fertilisation in causing this relationship, as it is not driven by traits such as polyploidy or annual life history whose evolution is sometimes correlated with selfing. Furthermore, we find that selfers occur at higher maximum latitudes and that disparity in range size between selfers and outcrossers increases with time since their evolutionary divergence. Together, these results show that autonomous reproduction--a critical biological trait that eliminates mate limitation and thus potentially increases the probability of establishment--increases range size.
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Affiliation(s)
- Dena Grossenbacher
- Department of Plant Biology, University of Minnesota, St. Paul, MN, 55108, USA
| | | | - Emma E Goldberg
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN, 55108, USA
| | - Yaniv Brandvain
- Department of Plant Biology, University of Minnesota, St. Paul, MN, 55108, USA
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107
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Burgarella C, Gayral P, Ballenghien M, Bernard A, David P, Jarne P, Correa A, Hurtrez-Boussès S, Escobar J, Galtier N, Glémin S. Molecular Evolution of Freshwater Snails with Contrasting Mating Systems. Mol Biol Evol 2015; 32:2403-16. [PMID: 25980005 DOI: 10.1093/molbev/msv121] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Because mating systems affect population genetics and ecology, they are expected to impact the molecular evolution of species. Self-fertilizing species experience reduced effective population size, recombination rates, and heterozygosity, which in turn should decrease the efficacy of natural selection, both adaptive and purifying, and the strength of meiotic drive processes such as GC-biased gene conversion. The empirical evidence is only partly congruent with these predictions, depending on the analyzed species, some, but not all, of the expected effects have been observed. One possible reason is that self-fertilization is an evolutionary dead-end, so that most current selfers recently evolved self-fertilization, and their genome has not yet been strongly impacted by selfing. Here, we investigate the molecular evolution of two groups of freshwater snails in which mating systems have likely been stable for several millions of years. Analyzing coding sequence polymorphism, divergence, and expression levels, we report a strongly reduced genetic diversity, decreased efficacy of purifying selection, slower rate of adaptive evolution, and weakened codon usage bias/GC-biased gene conversion in the selfer Galba compared with the outcrosser Physa, in full agreement with theoretical expectations. Our results demonstrate that self-fertilization, when effective in the long run, is a major driver of population genomic and molecular evolutionary processes. Despite the genomic effects of selfing, Galba truncatula seems to escape the demographic consequences of the genetic load. We suggest that the particular ecology of the species may buffer the negative consequences of selfing, shedding new light on the dead-end hypothesis.
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Affiliation(s)
- Concetta Burgarella
- Institut des Sciences de l'Evolution, UMR, CNRS 5554, Université Montpellier II, Montpellier, France
| | - Philippe Gayral
- Institut des Sciences de l'Evolution, UMR, CNRS 5554, Université Montpellier II, Montpellier, France
| | - Marion Ballenghien
- Institut des Sciences de l'Evolution, UMR, CNRS 5554, Université Montpellier II, Montpellier, France
| | - Aurélien Bernard
- Institut des Sciences de l'Evolution, UMR, CNRS 5554, Université Montpellier II, Montpellier, France
| | | | | | - Ana Correa
- MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution, Contrôle), UMR (UM1-UM2-CNRS 5290-IRD224), IRD, Montpellier, France
| | - Sylvie Hurtrez-Boussès
- MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution, Contrôle), UMR (UM1-UM2-CNRS 5290-IRD224), IRD, Montpellier, France
| | - Juan Escobar
- Institut des Sciences de l'Evolution, UMR, CNRS 5554, Université Montpellier II, Montpellier, France
| | - Nicolas Galtier
- Institut des Sciences de l'Evolution, UMR, CNRS 5554, Université Montpellier II, Montpellier, France
| | - Sylvain Glémin
- Institut des Sciences de l'Evolution, UMR, CNRS 5554, Université Montpellier II, Montpellier, France
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108
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Maintenance of Quantitative Genetic Variance Under Partial Self-Fertilization, with Implications for Evolution of Selfing. Genetics 2015; 200:891-906. [PMID: 25969460 DOI: 10.1534/genetics.115.176693] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 05/01/2015] [Indexed: 12/16/2022] Open
Abstract
We analyze two models of the maintenance of quantitative genetic variance in a mixed-mating system of self-fertilization and outcrossing. In both models purely additive genetic variance is maintained by mutation and recombination under stabilizing selection on the phenotype of one or more quantitative characters. The Gaussian allele model (GAM) involves a finite number of unlinked loci in an infinitely large population, with a normal distribution of allelic effects at each locus within lineages selfed for τ consecutive generations since their last outcross. The infinitesimal model for partial selfing (IMS) involves an infinite number of loci in a large but finite population, with a normal distribution of breeding values in lineages of selfing age τ. In both models a stable equilibrium genetic variance exists, the outcrossed equilibrium, nearly equal to that under random mating, for all selfing rates, r, up to critical value, [Formula: see text], the purging threshold, which approximately equals the mean fitness under random mating relative to that under complete selfing. In the GAM a second stable equilibrium, the purged equilibrium, exists for any positive selfing rate, with genetic variance less than or equal to that under pure selfing; as r increases above [Formula: see text] the outcrossed equilibrium collapses sharply to the purged equilibrium genetic variance. In the IMS a single stable equilibrium genetic variance exists at each selfing rate; as r increases above [Formula: see text] the equilibrium genetic variance drops sharply and then declines gradually to that maintained under complete selfing. The implications for evolution of selfing rates, and for adaptive evolution and persistence of predominantly selfing species, provide a theoretical basis for the classical view of Stebbins that predominant selfing constitutes an "evolutionary dead end."
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109
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Turchetto C, Lima JS, Rodrigues DM, Bonatto SL, Freitas LB. Pollen dispersal and breeding structure in a hawkmoth-pollinated Pampa grasslands species Petunia axillaris (Solanaceae). ANNALS OF BOTANY 2015; 115:939-48. [PMID: 25808656 PMCID: PMC4407064 DOI: 10.1093/aob/mcv025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/03/2015] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS The evolution of selfing is one of the most common transitions in flowering plants, and this change in mating pattern has important systematic and ecological consequences because it often initiates reproductive isolation and speciation. Petunia axillaris (Solanaceae) includes three allopatric subspecies widely distributed in temperate South America that present different degrees of self-compatibity and incompatibility. One of these subspecies is co-distributed with P. exserta in a restricted area and presents a complex, not well-understood mating system. Artificial crossing experiments suggest a complex system of mating in this sympatric area. The main aims of this study were to estimate the pollen dispersal distance and to evaluate the breeding structure of P. axillaris subsp. axillaris, a hawkmoth-pollinated taxon from this sympatric zone. METHODS Pollen dispersal distance was compared with nearest-neighbours distance, and the differentiation in the pollen pool among mother plants was estimated. In addition, the correlation between genetic differentiation and spatial distance among plants was tested. All adult individuals (252) within a space of 2800 m(2) and 15 open-pollinated progeny (285 seedlings) were analysed. Genetic analyses were based on 12 polymorphic microsatellite loci. KEY RESULTS A high proportion of self-pollination was found, indicating a mixed-mating system. The maximum pollen dispersal distance was 1013 m, but most pollination events (96 %) occurred at a distance of 0 m, predominantly in an inbreeding system. Both parents among sampled individuals could be identifed in 60-85 % of the progeny. CONCLUSIONS The results show that most pollen dispersal in the hawkmoth-pollinated P. axillaris subsp. axillaris occurs within populations and there is a high proportion of inbreeding. This mating system appears to favour species integrity in a secondary contact zone with the congener species P. exserta.
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Affiliation(s)
- Caroline Turchetto
- Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, PO Box 15053, Porto Alegre, Brazil, Laboratory of Genetic Diversity, Universidade Federal de Goiás, PO Box 131, 74001-970 Goiania, GO, Brazil and Laboratory of Genomic and Molecular Biology, Pontifícia Universidade Católica do Rio Grande do Sul, Ipiranga 6681, 90610-001 Porto Alegre, RS, Brazil
| | - Jacqueline S Lima
- Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, PO Box 15053, Porto Alegre, Brazil, Laboratory of Genetic Diversity, Universidade Federal de Goiás, PO Box 131, 74001-970 Goiania, GO, Brazil and Laboratory of Genomic and Molecular Biology, Pontifícia Universidade Católica do Rio Grande do Sul, Ipiranga 6681, 90610-001 Porto Alegre, RS, Brazil
| | - Daniele M Rodrigues
- Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, PO Box 15053, Porto Alegre, Brazil, Laboratory of Genetic Diversity, Universidade Federal de Goiás, PO Box 131, 74001-970 Goiania, GO, Brazil and Laboratory of Genomic and Molecular Biology, Pontifícia Universidade Católica do Rio Grande do Sul, Ipiranga 6681, 90610-001 Porto Alegre, RS, Brazil
| | - Sandro L Bonatto
- Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, PO Box 15053, Porto Alegre, Brazil, Laboratory of Genetic Diversity, Universidade Federal de Goiás, PO Box 131, 74001-970 Goiania, GO, Brazil and Laboratory of Genomic and Molecular Biology, Pontifícia Universidade Católica do Rio Grande do Sul, Ipiranga 6681, 90610-001 Porto Alegre, RS, Brazil
| | - Loreta B Freitas
- Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, PO Box 15053, Porto Alegre, Brazil, Laboratory of Genetic Diversity, Universidade Federal de Goiás, PO Box 131, 74001-970 Goiania, GO, Brazil and Laboratory of Genomic and Molecular Biology, Pontifícia Universidade Católica do Rio Grande do Sul, Ipiranga 6681, 90610-001 Porto Alegre, RS, Brazil
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110
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Pannell JR. Evolution of the mating system in colonizing plants. Mol Ecol 2015; 24:2018-37. [DOI: 10.1111/mec.13087] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/12/2015] [Accepted: 01/15/2015] [Indexed: 12/16/2022]
Affiliation(s)
- John R. Pannell
- Department of Ecology and Evolution; University of Lausanne; Biophore Building 1015 Lausanne Switzerland
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111
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Barrett SCH, Arunkumar R, Wright SI. The demography and population genomics of evolutionary transitions to self-fertilization in plants. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0344. [PMID: 24958918 DOI: 10.1098/rstb.2013.0344] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The evolution of self-fertilization from outcrossing has occurred on numerous occasions in flowering plants. This shift in mating system profoundly influences the morphology, ecology, genetics and evolution of selfing lineages. As a result, there has been sustained interest in understanding the mechanisms driving the evolution of selfing and its environmental context. Recently, patterns of molecular variation have been used to make inferences about the selective mechanisms associated with mating system transitions. However, these inferences can be complicated by the action of linked selection following the transition. Here, using multilocus simulations and comparative molecular data from related selfers and outcrossers, we demonstrate that there is little evidence for strong bottlenecks associated with initial transitions to selfing, and our simulation results cast doubt on whether it is possible to infer the role of bottlenecks associated with reproductive assurance in the evolution of selfing. They indicate that the effects of background selection on the loss of diversity and efficacy of selection occur rapidly following the shift to high selfing. Future comparative studies that integrate explicit ecological and genomic details are necessary for quantifying the independent and joint effects of selection and demography on transitions to selfing and the loss of genetic diversity.
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Affiliation(s)
- Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
| | - Ramesh Arunkumar
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
| | - Stephen I Wright
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
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112
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The evolution of selfing is accompanied by reduced efficacy of selection and purging of deleterious mutations. Genetics 2014; 199:817-29. [PMID: 25552275 DOI: 10.1534/genetics.114.172809] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The transition from outcrossing to selfing is predicted to reduce the genome-wide efficacy of selection because of the lower effective population size (Ne) that accompanies this change in mating system. However, strongly recessive deleterious mutations exposed in the homozygous backgrounds of selfers should be under strong purifying selection. Here, we examine estimates of the distribution of fitness effects (DFE) and changes in the magnitude of effective selection coefficients (Nes) acting on mutations during the transition from outcrossing to selfing. Using forward simulations, we investigated the ability of a DFE inference approach to detect the joint influence of mating system and the dominance of deleterious mutations on selection efficacy. We investigated predictions from our simulations in the annual plant Eichhornia paniculata, in which selfing has evolved from outcrossing on multiple occasions. We used range-wide sampling to generate population genomic datasets and identified nonsynonymous and synonymous polymorphisms segregating in outcrossing and selfing populations. We found that the transition to selfing was accompanied by a change in the DFE, with a larger fraction of effectively neutral sites (Nes < 1), a result consistent with the effects of reduced Ne in selfers. Moreover, an increased proportion of sites in selfers were under strong purifying selection (Nes > 100), and simulations suggest that this is due to the exposure of recessive deleterious mutations. We conclude that the transition to selfing has been accompanied by the genome-wide influences of reduced Ne and strong purifying selection against deleterious recessive mutations, an example of purging at the molecular level.
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113
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The influence of pleiotropy between viability and pollen fates on mating system evolution. Theor Popul Biol 2014; 99:7-17. [PMID: 25448089 DOI: 10.1016/j.tpb.2014.10.005] [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: 09/05/2014] [Revised: 10/13/2014] [Accepted: 10/18/2014] [Indexed: 11/23/2022]
Abstract
Floral displays are functionally and genetically integrated structures, so modifications to display will likely affect multiple fitness components (pleiotropy), including pollen export and self-pollination, and therefore selfing rate. Consequently, the great diversities of floral displays and of mating systems found among angiosperms have likely co-evolved. I extend previous models of mating system evolution to determine how pleiotropy that links viability (e.g., probability of survival to reproduction) and the allocation of pollen for export and selfing affects the evolution of selfing, outcrossing, and in particular, mixed mating. I show that the outcome depends on how pollen shifts from being exported, unused, or used for selfing. Furthermore, pleiotropy that affects viability can explain observations not addressed by previous theory, including the evolution of mixed mating despite high inbreeding depression in the absence of pollen-limitation. Therefore, pleiotropy may play a key role in explaining selfing rates for such species that exhibit otherwise enigmatic mating systems.
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114
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High lifetime inbreeding depression counteracts the reproductive assurance benefit of selfing in a mass-flowering shrub. BMC Evol Biol 2014; 14:243. [PMID: 25433917 PMCID: PMC4258271 DOI: 10.1186/s12862-014-0243-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 11/14/2014] [Indexed: 11/17/2022] Open
Abstract
Background Decreases in mate and/or pollinator availability would be expected to affect the selective pressure on plant mating systems. An increase in self-fertilization may evolve to compensate for the negative effects of pollination failure. However, the benefit of selfing in variable pollination environments depends on the relative fitnesses of selfed and outcrossed progeny. We investigated the potential for selfing to provide reproductive assurance over the lifetime of a long-lived perennial species and its variation between plant patches of various sizes. Patch size is likely to affect mate and pollinator availabilities, thereby affecting pollination success and the rate of selfing. We estimated fruit and seed set, reproductive assurance, self-compatibility, the multilocus patch selfing rate and lifetime inbreeding depression in natural patches of Rhododendron ferrugineum (Ericaceae), a mass-flowering species characterized by considerable patch size variation (as estimated by the total number of inflorescences). Results Open seed set declined linearly with increasing patch size, whereas pollinator-mediated seed set (emasculated flowers) was not significantly affected. Progeny array analysis indicated that the selfing rate declined with increasing patch size, consistent with greater reproductive assurance in small sparse patches than in large, dense patches. However, fruit set and adult fitness decreased with decreasing patch size, with an estimated mean lifetime inbreeding depression of 0.9 (obtained by comparing F values in adults and progenies). Conclusions Lifetime inbreeding depression strongly counteracts the advantage of reproductive assurance due to selfing in this long-lived species. The poor fitness of selfed offspring should counteract any evolution towards selfing, despite its potential to alleviate the negative consequences of pollen limitation. This study highlights the need to estimate lifetime inbreeding depression, together with mating system and pollination parameters, if we are to understand the actual benefit of selfing and avoid the overestimation of reproductive assurance. Electronic supplementary material The online version of this article (doi:10.1186/s12862-014-0243-7) contains supplementary material, which is available to authorized users.
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115
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Lepers C, Dufay M, Billiard S. How does pollination mutualism affect the evolution of prior self-fertilization? A model. Evolution 2014; 68:3581-98. [PMID: 25314084 DOI: 10.1111/evo.12533] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/28/2014] [Indexed: 11/27/2022]
Abstract
The mode of pollination is often neglected regarding the evolution of selfing. Yet the distribution of mating systems seems to depend on the mode of pollination, and pollinators are likely to interfere with selfing evolution, since they can cause strong selective pressures on floral traits. Most selfing species reduce their investment in reproduction, and display smaller flowers, with less nectar and scents (referred to as selfing syndrome). We model the evolution of prior selfing when it affects both the demography of plants and pollinators and the investment of plants in pollination. Including the selfing syndrome in the model allows to predict several outcomes: plants can evolve either toward complete outcrossing, complete selfing, or to a stable mixed-mating system, even when inbreeding depression is high. We predict that the evolution to high prior selfing could lead to evolutionary suicides, highlighting the importance of merging demography and evolution in models. The consequence of the selfing syndrome on plant-pollinator interactions could be a widespread mechanism driving the evolution of selfing in animal-pollinated taxa.
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Affiliation(s)
- Clotilde Lepers
- Laboratoire d'Evolution Ecologie et Paleontologie, UMR CNRS 8198 Bâtiment SN2, Université de Lille, F-59655, Villeneuve d'Ascq Cedex, France.
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116
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Ng J, Smith SD. How traits shape trees: new approaches for detecting character state-dependent lineage diversification. J Evol Biol 2014; 27:2035-45. [PMID: 25066512 DOI: 10.1111/jeb.12460] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 12/30/2022]
Abstract
Biologists have long sought to understand the processes underlying disparities in clade size across the tree of life and the extent to which such clade size differences can be attributed to the evolution of particular traits. The association of certain character states with species-rich clades suggests that trait evolution can lead to increased diversification, but such a pattern could also arise due other processes, such as directional trait evolution. Recent advances in phylogenetic comparative methods have provided new statistical approaches for distinguishing between these intertwined and potentially confounded macroevolutionary processes. Here, we review the historical development of methods for detecting state-dependent diversification and explore what new methods have revealed about classic examples of traits that affect diversification, including evolutionary dead ends, key innovations and geographic traits. Applications of these methods thus far collectively suggest that trait diversity commonly arises through the complex interplay between transition, speciation and extinction rates and that long hypothesized evolutionary dead ends and key innovations are instead often cases of directional trends in trait evolution.
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Affiliation(s)
- J Ng
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
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Käfer J, de Boer HJ, Mousset S, Kool A, Dufay M, Marais GAB. Dioecy is associated with higher diversification rates in flowering plants. J Evol Biol 2014; 27:1478-90. [PMID: 24797166 DOI: 10.1111/jeb.12385] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 03/23/2014] [Accepted: 03/28/2014] [Indexed: 11/30/2022]
Abstract
In angiosperms, dioecious clades tend to have fewer species than their nondioecious sister clades. This departure from the expected equal species richness in the standard sister clade test has been interpreted as implying that dioecious clades diversify less and has initiated a series of studies suggesting that dioecy might be an 'evolutionary dead end'. However, two of us recently showed that the 'equal species richness' null hypothesis is not valid in the case of derived char acters, such as dioecy, and proposed a new test for sister clade comparisons; preliminary results, using a data set available in the litterature, indicated that dioecious clades migth diversify more than expected. However, it is crucial for this new test to distinguish between ancestral and derived cases of dioecy, a criterion that was not taken into account in the available data set. Here, we present a new data set that was obtained by searching the phylogenetic literature on more than 600 completely dioecious angiosperm genera and identifying 115 sister clade pairs for which dioecy is likely to be derived (including > 50% of the dioecious species). Applying the new sister clade test to this new dataset, we confirm the preliminary result that dioecy is associated with an increased diversification rate, a result that does not support the idea that dioecy is an evolutionary dead end in angiosperms. The traits usually associated with dioecy, that is, an arborescent growth form, abiotic pollination, fleshy fruits or a tropical distribution, do not influence the diversification rate. Rather than a low diversification rate, the observed species richness patterns of dioecious clades seem to be better explained by a low transition rate to dioecy and frequent losses.
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Affiliation(s)
- J Käfer
- Université Lyon 1, Centre National de la Recherche Scientifique, UMR5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France
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118
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Salcedo A, Kalisz S, Wright SI. Limited genomic consequences of mixed mating in the recently derived sister species pair, Collinsia concolor and Collinsia parryi. J Evol Biol 2014; 27:1400-12. [PMID: 24796997 DOI: 10.1111/jeb.12384] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 03/07/2014] [Accepted: 03/12/2014] [Indexed: 11/30/2022]
Abstract
Highly selfing species often show reduced effective population sizes and reduced selection efficacy. Whether mixed mating species, which produce both self and outcross progeny, show similar patterns of diversity and selection remains less clear. Examination of patterns of molecular evolution and levels of diversity in species with mixed mating systems can be particularly useful for investigating the relative importance of linked selection and demographic effects on diversity and the efficacy of selection, as the effects of linked selection should be minimal in mixed mating populations, although severe bottlenecks tied to founder events could still be frequent. To begin to address this gap, we assembled and analysed the transcriptomes of individuals from a recently diverged mixed mating sister species pair in the self-compatible genus, Collinsia. The de novo assembly of 52 and 37 Mbp C. concolor and C. parryi transcriptomes resulted in ~40 000 and ~55 000 contigs, respectively, both with an average contig size ~945. We observed a high ratio of shared polymorphisms to fixed differences in the species pair and minimal differences between species in the ratio of synonymous to replacement substitutions or codon usage bias implying comparable effective population sizes throughout species divergence. Our results suggest that differences in effective population size and selection efficacy in mixed mating taxa shortly after their divergence may be minimal and are likely influenced by fluctuating mating systems and population sizes.
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Affiliation(s)
- A Salcedo
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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119
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Vekemans X, Poux C, Goubet PM, Castric V. The evolution of selfing from outcrossing ancestors in Brassicaceae: what have we learned from variation at the S-locus? J Evol Biol 2014; 27:1372-85. [PMID: 24725152 DOI: 10.1111/jeb.12372] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 03/06/2014] [Accepted: 03/10/2014] [Indexed: 12/01/2022]
Abstract
Evolutionary transitions between mating systems have occurred repetitively and independently in flowering plants. One of the most spectacular advances of the recent empirical literature in the field was the discovery of the underlying genetic machinery, which provides the opportunity to retrospectively document the scenario of the outcrossing to selfing transitions in a phylogenetic perspective. In this review, we explore the literature describing patterns of polymorphism and molecular evolution of the locus controlling self-incompatibility (S-locus) in selfing species of the Brassicaceae family in order to document the transition from outcrossing to selfing, a retrospective approach that we describe as the 'mating system genes approach'. The data point to strikingly contrasted scenarios of transition from outcrossing to selfing. We also perform original analyses of the fully sequenced genomes of four species showing self-compatibility, to compare the orthologous S-locus region with that of functional S-locus haplotypes. Phylogenetic analyses suggest that all species we investigated evolved independently towards loss of self-incompatibility, and in most cases almost intact sequences of either of the two S-locus genes suggest that these transitions occurred relatively recently. The S-locus region in Aethionema arabicum, representing the most basal lineage of Brassicaceae, showed unusual patterns so that our analysis could not determine whether self-incompatibility was lost secondarily, or evolved in the core Brassicaceae after the split with this basal lineage. Although the approach we detail can only be used when mating system genes have been identified in a clade, we suggest that its integration with phylogenetic and population genetic approaches should help determine the main routes of this predominant mating system shift in plants.
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Affiliation(s)
- X Vekemans
- Laboratoire de Génétique et Evolution des Populations Végétales, UMR CNRS 8198, Université Lille 1, Villeneuve d'Ascq Cedex, France
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120
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Stone JL, VanWyk EJ, Hale JR. Transmission advantage favors selfing allele in experimental populations of self-incompatible Witheringia solanacea (solanaceae). Evolution 2014; 68:1845-55. [PMID: 24713065 DOI: 10.1111/evo.12419] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 03/18/2014] [Indexed: 11/30/2022]
Abstract
The evolution of self-fertilization is one of the most commonly traversed transitions in flowering plants, with profound implications for population genetic structure and evolutionary potential. We investigated factors influencing this transition using Witheringia solanacea, a predominantly self-incompatible (SI) species within which self-compatible (SC) genotypes have been identified. We showed that self-compatibility in this species segregates with variation at the S-locus as inherited by plants in F1 and F2 generations. To examine reproductive assurance and the transmission advantage of selfing, we placed SC and SI genotypes in genetically replicated gardens and monitored male and female reproductive success, as well as selfing rates of SC plants. Self-compatibility did not lead to increased fruit or seed set, even under conditions of pollinator scarcity, and the realized selfing rate of SC plants was less than 10%. SC plants had higher fruit abortion rates, consistent with previous evidence showing strong inbreeding depression at the embryonic stage. Although the selfing allele did not provide reproductive assurance under observed conditions, it also did not cause pollen discounting, so the transmission advantage of selfing should promote its spread. Given observed numbers of S-alleles and selfing rates, self-compatibility should spread even under conditions of exceedingly high initial inbreeding depression.
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Affiliation(s)
- Judy L Stone
- Department of Biology, Colby College, Waterville, Maine, 04901.
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121
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Glémin S, Muyle A. Mating systems and selection efficacy: a test using chloroplastic sequence data in Angiosperms. J Evol Biol 2014; 27:1386-99. [PMID: 24674012 DOI: 10.1111/jeb.12356] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 12/26/2022]
Abstract
Selfing is assumed to reduce selection efficacy, especially purifying selection. This can be tested using molecular data, for example by comparing the Dn/Ds ratio between selfing and outcrossing lineages. So far, little evidence of relaxed selection against weakly deleterious mutations (as inferred by a higher Dn/Ds ratio) in selfers as compared to outcrossers has been found, contrary to the pattern often observed between asexual and sexual lineages. However, few groups have been studied to date. To further test this hypothesis, we compiled and analysed chloroplastic sequence data sets in several plant groups. We found a general trend towards relaxed selection in selfers in our data sets but with weak statistical support. Simulations suggested that the results were compatible with weak-to-moderate Dn/Ds ratio differences in selfing lineages. Simple theoretical predictions also showed that the ability to detect relaxed selection in selfers could strongly depend on the distribution of the effects of deleterious mutations on fitness. Our results are compatible with a recent origin of selfing lineages whereby deleterious mutations potentially have a strong impact on population extinction or with a more ancient origin but without a marked effect of deleterious mutations on the extinction dynamics.
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Affiliation(s)
- S Glémin
- Institut des Sciences de l'Evolution de Montpellier, UMR CNRS 5554, Montpellier, France
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122
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Armbruster WS. Floral specialization and angiosperm diversity: phenotypic divergence, fitness trade-offs and realized pollination accuracy. AOB PLANTS 2014; 6:plu003. [PMID: 24790124 PMCID: PMC4038416 DOI: 10.1093/aobpla/plu003] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 01/05/2014] [Indexed: 05/08/2023]
Abstract
Plant reproduction by means of flowers has long been thought to promote the success and diversification of angiosperms. It remains unclear, however, how this success has come about. Do flowers, and their capacity to have specialized functions, increase speciation rates or decrease extinction rates? Is floral specialization fundamental or incidental to the diversification? Some studies suggest that the conclusions we draw about the role of flowers in the diversification and increased phenotypic disparity (phenotypic diversity) of angiosperms depends on the system. For orchids, for example, specialized pollination may have increased speciation rates, in part because in most orchids pollen is packed in discrete units so that pollination is precise enough to contribute to reproductive isolation. In most plants, however, granular pollen results in low realized pollination precision, and thus key innovations involving flowers more likely reflect reduced extinction rates combined with opportunities for evolution of greater phenotypic disparity (phenotypic diversity) and occupation of new niches. Understanding the causes and consequences of the evolution of specialized flowers requires knowledge of both the selective regimes and the potential fitness trade-offs in using more than one pollinator functional group. The study of floral function and flowering-plant diversification remains a vibrant evolutionary field. Application of new methods, from measuring natural selection to estimating speciation rates, holds much promise for improving our understanding of the relationship between floral specialization and evolutionary success.
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Affiliation(s)
- W. Scott Armbruster
- School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000, USA
- Department of Biology, Norwegian University of Science & Technology, Trondheim N-7491, Norway
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123
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Schoebel CN, Stewart J, Gruenwald NJ, Rigling D, Prospero S. Population history and pathways of spread of the plant pathogen Phytophthora plurivora. PLoS One 2014; 9:e85368. [PMID: 24427303 PMCID: PMC3888410 DOI: 10.1371/journal.pone.0085368] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/25/2013] [Indexed: 12/05/2022] Open
Abstract
Human activity has been shown to considerably affect the spread of dangerous pests and pathogens worldwide. Therefore, strict regulations of international trade exist for particularly harmful pathogenic organisms. Phytophthora plurivora, which is not subject to regulations, is a plant pathogen frequently found on a broad range of host species, both in natural and artificial environments. It is supposed to be native to Europe while resident populations are also present in the US. We characterized a hierarchical sample of isolates from Europe and the US and conducted coalescent-, migration, and population genetic analysis of sequence and microsatellite data, to determine the pathways of spread and the demographic history of this pathogen. We found P. plurivora populations to be moderately diverse but not geographically structured. High levels of gene flow were observed within Europe and unidirectional from Europe to the US. Coalescent analyses revealed a signal of a recent expansion of the global P. plurivora population. Our study shows that P. plurivora has most likely been spread around the world by nursery trade of diseased plant material. In particular, P. plurivora was introduced into the US from Europe. International trade has allowed the pathogen to colonize new environments and/or hosts, resulting in population growth.
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Affiliation(s)
- Corine N. Schoebel
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Department of Biodiversity and Conservation Biology, Birmensdorf, Switzerland
| | - Jane Stewart
- USDA-ARS-Horticultural Crops Research Laboratory, Corvallis, Oregon, United States of America
- Department of Botany & Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Niklaus J. Gruenwald
- USDA-ARS-Horticultural Crops Research Laboratory, Corvallis, Oregon, United States of America
- Department of Botany & Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Daniel Rigling
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Department of Biodiversity and Conservation Biology, Birmensdorf, Switzerland
| | - Simone Prospero
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Department of Biodiversity and Conservation Biology, Birmensdorf, Switzerland
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124
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Abstract
Self-fertilization is generally seen to be disadvantageous in the long term. It increases genetic drift, which subsequently reduces polymorphism and the efficiency of selection, which also challenges adaptation. However, high selfing rates can increase the fixation probability of recessive beneficial mutations, but existing theory has generally not accounted for the effect of linked sites. Here, we analyze a model for the fixation probability of deleterious mutants that hitchhike with selective sweeps in diploid, partially selfing populations. Approximate analytical solutions show that, conditional on the sweep not being lost by drift, higher inbreeding rates increase the fixation probability of the deleterious allele, due to the resulting reduction in polymorphism and effective recombination. When extending the analysis to consider a distribution of deleterious alleles, as well as the average fitness increase after a sweep, we find that beneficial alleles generally need to be more recessive than the previously assumed dominance threshold (h < 1/2) for selfing to be beneficial from one-locus theory. Our results highlight that recombination aiding the efficiency of selection on multiple loci amplifies the fitness benefits of outcrossing over selfing, compared to results obtained from one-locus theory. This effect additionally increases the parameter range under which obligate outcrossing is beneficial over partial selfing.
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125
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Jordaens K, Van Houtte N, Helsen P, Breugelmans K, Jaksons P, Backeljau T. Mixed breeding system in the hermaphroditic land slug Arion intermedius (Stylommatophora, Arionidae). Hereditas 2013; 150:45-52. [PMID: 24164457 DOI: 10.1111/j.1601-5223.2013.02272.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Theory suggests that hermaphroditic plants and animals should be either entirely outcrossing or entirely selfing. As such, very few hermaphroditic plants and basommatophoran snails have a mixed breeding system. However, reliable estimates of selfing rates are lacking for most hermaphroditic animals. This partly prevents to delineate the relative contributions of the selective factors that determine selfing and outcrossing rates in hermaphroditic animal taxa. Here, we studied the population genetic structure of, and breeding system in, 11 populations of the hermaphroditic land slug Arion intermedius using five polymorphic microsatellite loci. Moreover, genotype frequencies deviated significantly from Hardy-Weinberg equilibrium expectations for most of the loci in all populations suggesting some level of selfing. Estimates of the selfing level s, suggest moderate levels of outcrossing (mean s based on FIS = 0.84; mean s based on the two-locus heterozygosity disequilibrium = 0.20, or with a ML approach = 0.22). Our study therefore suggests that A. intermedius has a mixed breeding system. A re-analysis of allozyme data from another arionid slug ( subgenus Carinarion) indicates that mixed breeding may be more common in arionid slugs than hitherto was assumed. These results seem therefore at variance with current theoretical and empirical predictions and opens perspectives for the study on the evolutionary factors driving mixed breeding systems in animals.
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Affiliation(s)
- Kurt Jordaens
- Royal Museum for Central Africa, Tervuren, BelgiumUniversity of Antwerp, Antwerp, BelgiumRoyal Belgian Institute of Natural Sciences, Brussels, Belgium
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126
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Barrett SCH. The evolution of plant reproductive systems: how often are transitions irreversible? Proc Biol Sci 2013; 280:20130913. [PMID: 23825207 PMCID: PMC3712442 DOI: 10.1098/rspb.2013.0913] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 06/03/2013] [Indexed: 11/12/2022] Open
Abstract
Flowering plants are characterized by striking variation in reproductive systems, and the evolutionary lability of their sexual traits is often considered a major driver of lineage diversification. But, evolutionary transitions in reproductive form and function are never entirely unconstrained and many changes exhibit strong directionality. Here, I consider why this occurs by examining transitions in pollination, mating and sexual systems, some of which have been considered irreversible. Among pollination systems, shifts from bee to hummingbird pollination are rarely reversible, whereas transitions from animal to wind pollination are occasionally reversed. Specialized pollination systems can become destabilized through a loss of pollinator service resulting in a return to generalized pollination, or more commonly a reliance on self-pollination. Homomorphic and heteromorphic self-incompatibility systems have multiple origins but breakdown to self-compatibility occurs much more frequently with little evidence for subsequent gains, at least over short time-spans. Similarly, numerous examples of the shift from outcrossing to predominant self-fertilization are known, but cases of reversal are very limited supporting the view that autogamy usually represents an evolutionary dead-end. The evolution of dioecy from hermaphroditism has also been considered irreversible, although recent evidence indicates that the occurrence of sex inconstancy and hybridization can lead to the origin of derived sexual systems from dioecy. The directionality of many transitions clearly refutes the notion of unconstrained reproductive flexibility, but novel adaptive solutions generally do not retrace earlier patterns of trait evolution.
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Affiliation(s)
- Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada.
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127
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Thomann M, Imbert E, Devaux C, Cheptou PO. Flowering plants under global pollinator decline. TRENDS IN PLANT SCIENCE 2013; 18:353-359. [PMID: 23688727 DOI: 10.1016/j.tplants.2013.04.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 04/04/2013] [Accepted: 04/05/2013] [Indexed: 06/02/2023]
Abstract
There is now compelling evidence of a reduction of pollinator richness and density at a global scale. In this opinion article, we argue that such pollinator decline intensifies pollen limitation and reduces plant reproductive success, threatening natural populations of extinction. We use genetic architecture and selection experiments on floral traits and evaluate the potential for plant reproductive strategies to adapt rapidly to new pollination environments. We propose that plant reproductive strategies could adapt to the current pollinator decline by decreasing or increasing their reliance to pollinators, for example, increasing autonomous selfing or reinforcing interactions with pollinators. We further discuss if and how adaptation of plant reproductive strategies can buffer the demographic consequences of pollinator decline, and possibly rescue plant populations from extinction.
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Affiliation(s)
- Michel Thomann
- UMR 5175 CEFE, Centre d'Ecologie Fonctionnelle et Evolutive (CNRS), 1919 Route de Mende, F-34293 Montpellier Cedex 05, France
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