scholarly journals Variation in competitive ability with mating system, ploidy and range expansion in four Capsella species

2017 ◽  
Author(s):  
Xuyue Yang ◽  
Martin Lascoux ◽  
Sylvain Glémin
Keyword(s):  
Mating System ◽  
Range Expansion ◽  
Evolutionary Biology ◽  
Competitive Ability ◽  
Vegetative Traits ◽  
Evolutionary Trajectories ◽  
Self Fertilization ◽  
Peer Community ◽  
Meta Analyses ◽  
Selfing Species

AbstractThis preprint has been reviewed and recommended by Peer Community In Evolutionary Biology (https://dx.doi.org/10.24072/pci.evolbiol.100054)Self-fertilization is often associated with ecological traits corresponding to the ruderal strategy in Grime’s Competitive-Stress-tolerant-Ruderal (CSR) classification of ecological strategies. Consequently, selfers are expected to be less competitive than outcrossers, either because of a colonization/competition trade-off or because of the deleterious genetic effects of selfing. Range expansion could reduce further competitive ability while polyploidy could mitigate the effects of selfing. Although suggested by meta-analyses, these predictions have not been directly tested yet. We compared the competitive ability of four Capsella species differing by their mating system and ploidy level. For vegetative traits we found no difference in competitive ability neither among species nor among populations. For flower production, we found that the two diploid selfing species (C. rubella and C. orientalis) were more sensitive to competition than the diploid outcrosser (C. grandiflora), and that the tetraploid selfer (C. bursa-pastoris) was intermediate. Within C. bursa-pastoris, we also found that sensitivity to competition increased in parallel to range expansion. These results highlight the possible roles of ecological context and ploidy in the evolutionary trajectories of selfing species.

scholarly journals Drivers of linkage disequilibrium across a species’ geographic range

PLoS Genetics ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. e1009477
Author(s):  
Kay Lucek ◽  
Yvonne Willi
Keyword(s):  
Linkage Disequilibrium ◽  
Mating System ◽  
Range Expansion ◽  
Evolutionary Biology ◽  
Demographic History ◽  
Similar Degree ◽  
Mutational Load ◽  
Arabidopsis Lyrata ◽  
Genome Wide ◽  
The Impact

While linkage disequilibrium (LD) is an important parameter in genetics and evolutionary biology, the drivers of LD remain elusive. Using whole-genome sequences from across a species’ range, we assessed the impact of demographic history and mating system on LD. Both range expansion and a shift from outcrossing to selfing in North AmericanArabidopsis lyratawere associated with increased average genome-wide LD. Our results indicate that range expansion increases short-distance LD at the farthest range edges by about the same amount as a shift to selfing. However, the extent over which LD in genic regions unfolds was shorter for range expansion compared to selfing. Linkage among putatively neutral variants and between neutral and deleterious variants increased to a similar degree with range expansion, providing support that genome-wide LD was positively associated with mutational load. As a consequence, LD combined with mutational load may decelerate range expansions and set range limits. Finally, a small number of genes were identified as LD outliers, suggesting that they experience selection by either of the two demographic processes. These included genes involved in flowering and photoperiod for range expansion, and the self-incompatibility locus for mating system.

scholarly journals Effects of partial selfing on the equilibrium genetic variance, mutation load and inbreeding depression under stabilizing selection

2017 ◽  
Author(s):  
Diala Abu Awad ◽  
Denis Roze
Keyword(s):  
Inbreeding Depression ◽  
Evolutionary Biology ◽  
Genetic Variance ◽  
Stabilizing Selection ◽  
Genetic Associations ◽  
Mutation Load ◽  
Recombination Rates ◽  
Self Fertilization ◽  
Selected Traits ◽  
Peer Community

ABSTRACTThis preprint has been reviewed and recommended by Peer Community In Evolutionary Biology (http://dx.doi.org/10.24072/pci.evolbiol.100041).The mating system of a species is expected to have important effects on its genetic diversity. In this paper, we explore the effects of partial selfing on the equilibrium genetic variance Vg, mutation load L and inbreeding depression δ under stabilizing selection acting on a arbitrary number n of quantitative traits coded by biallelic loci with additive effects. Overall, our model predicts a decrease in the equilibrium genetic variance with increasing selfing rates; however, the relationship between self-fertilization and the variables of interest depends on the strength of associations between loci, and three different regimes are observed. When the U/n ratio is low (where U is the total haploid mutation rate on selected traits) and effective recombination rates are sufficiently high, genetic associations between loci are negligible and the genetic variance, mutation load and inbreeding depression are well predicted by approximations based on single-locus models. For higher values of U/n and/or lower effective recombination, moderate genetic associations generated by epistasis tend to increase Vg, L and δ, this regime being well predicted by approximations including the effects of pairwise associations between loci. For yet higher values of U/n and/or lower effective recombination, a different regime is reached under which the maintenance of coadapted gene complexes reduces Vg, L and δ. Simulations indicate that the values of Vg, L and δ are little affected by assumptions regarding the number of possible alleles per locus.

Establishment of local adaptation in partly self-fertilizing populations

Genetics ◽  
2021 ◽  
Author(s):  
Bogi Trickovic ◽  
Sylvain Glémin
Keyword(s):  
Local Adaptation ◽  
Pollen Dispersal ◽  
Theoretical Background ◽  
Weak Selection ◽  
Dominance Level ◽  
Self Fertilization ◽  
Protected Polymorphism ◽  
And Migration ◽  
Closed Form Approximation ◽  
Selfing Species

Abstract Populations often inhabit multiple ecological patches and thus experience divergent selection, which can lead to local adaptation if migration is not strong enough to swamp locally adapted alleles. Conditions for the establishment of a locally advantageous allele have been studied in randomly mating populations. However, many species reproduce, at least partially, through self-fertilization, and how selfing affects local adaptation remains unclear and debated. Using a two-patch branching process formalism, we obtained a closed-form approximation under weak selection for the probability of establishment of a locally advantageous allele (P) for arbitrary selfing rate and dominance level, where selection is allowed to act on viability or fecundity, and migration can occur via seed or pollen dispersal. This solution is compared to diffusion approximation and used to investigate the consequences of a shift in a mating system on P, and the establishment of protected polymorphism. We find that selfing can either increase or decrease P, depending on the patterns of dominance in the two patches, and has conflicting effects on local adaptation. Globally, selfing favors local adaptation when locally advantageous alleles are (partially) recessive, when selection between patches is asymmetrical and when migration occurs through pollen rather than seed dispersal. These results establish a rigorous theoretical background to study heterogeneous selection and local adaptation in partially selfing species.

scholarly journals Mating System and Hybridity in Eucalyptus pauciflora

1977 ◽  
Vol 30 (4) ◽  
pp. 337 ◽  
Author(s):  
MA Phillips ◽  
AHD Brown
Keyword(s):  
Mating System ◽  
Outcrossing Rate ◽  
Seedling Stage ◽  
Average Heterozygosity ◽  
Evolutionary Advantage ◽  
Allozyme Polymorphisms ◽  
Self Fertilization

Allozyme polymorphisms at four loci expressed in seeds, and three other loci expressed in seedlings, were used to determine the outcrossing rate in three natural subalpine populations of snow gum (E. paucijlora). Based on the seed loci data, an estimated 37 % of seed was derived from self-fertilization and 63 % from random outcrossing. In the most elevated population the estimate after germination was similar. However, at lower elevations the frequency of effective self-fertilization estimated at the seedling stage was only 16 %. The less elevated populations also showed a greater average heterozygosity and a larger increase in heterozygosity in the adult over the progeny stages. Heterosis apparently operated differentially in these populations-it was more intense at the lower altitudes. Selection in favour of outcrossed individuals may be an important factor in checking the spread through the population of genes which promote self-fertilization, and which would otherwise enjoy an evolutionary advantage.

Floral trait variation and links to climate in the mixed-mating annual Clarkia pulchella

Botany ◽  
2018 ◽  
Vol 96 (7) ◽  
pp. 425-435 ◽  
Author(s):  
Devin E. Gamble ◽  
Megan Bontrager ◽  
Amy L. Angert
Keyword(s):  
Mating System ◽  
Common Garden ◽  
Moisture Stress ◽  
Floral Traits ◽  
Mixed Mating ◽  
Floral Trait ◽  
Local Climate ◽  
Self Fertilization ◽  
Clarkia Pulchella ◽  
Watering Treatment

The benefits of self-fertilization can vary across environments, leading to selection for different reproductive strategies and influencing the evolution of floral traits. Although stressful conditions have been suggested to favour self-pollination, the role of climate as a driver of mating-system variation is generally not well understood. Here, we investigate the contributions of local climate to intraspecific differences in mating-system traits in Clarkia pulchella Pursh in a common-garden growth chamber experiment. We also tested for plastic responses to soil moisture with watering treatments. Herkogamy (anther–stigma spacing) correlated positively with dichogamy (timing of anther–stigma receptivity) and date of first flower, and northern populations had smaller petals and flowered earlier in response to experimental drought. Watering treatment alone had little effect on traits, and dichogamy unexpectedly decreased with annual precipitation. Populations also differed in phenological response to watering treatment, based on precipitation and winter temperature of their origin, indicating that populations from cool and dry sites have greater plasticity under different levels of moisture stress. While some variation in floral traits is attributable to climate, further investigation into variation in pollinator communities and the indirect effects of climate on mating system can improve our understanding of the evolution of plant mating.

scholarly journals The demography and population genomics of evolutionary transitions to self-fertilization in plants

2014 ◽  
Vol 369 (1648) ◽  
pp. 20130344 ◽  
Author(s):  
Spencer C. H. Barrett ◽  
Ramesh Arunkumar ◽  
Stephen I. Wright
Keyword(s):  
Mating System ◽  
Population Genomics ◽  
Molecular Data ◽  
Reproductive Assurance ◽  
Evolutionary Transitions ◽  
Cast Doubt ◽  
Self Fertilization ◽  
Loss Of Diversity ◽  
Linked Selection

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.

scholarly journals Magnetosome Gene Duplication as an Important Driver in the Evolution of Magnetotaxis in the Alphaproteobacteria

mSystems ◽  
2019 ◽  
Vol 4 (5) ◽  
Author(s):  
Haijian Du ◽  
Wenyan Zhang ◽  
Wensi Zhang ◽  
Weijia Zhang ◽  
Hongmiao Pan ◽  
...  
Keyword(s):  
Gene Duplication ◽  
Gene Cluster ◽  
Geomagnetic Field ◽  
Evolutionary Biology ◽  
Genomic Analysis ◽  
Magnetotactic Bacteria ◽  
Duplication Event ◽  
Comparative Genomic ◽  
Content Type ◽  
Evolutionary Trajectories

ABSTRACT The evolution of microbial magnetoreception (or magnetotaxis) is of great interest in the fields of microbiology, evolutionary biology, biophysics, geomicrobiology, and geochemistry. Current genomic data from magnetotactic bacteria (MTB), the only prokaryotes known to be capable of sensing the Earth’s geomagnetic field, suggests an ancient origin of magnetotaxis in the domain Bacteria. Vertical inheritance, followed by multiple independent magnetosome gene cluster loss, is considered to be one of the major forces that drove the evolution of magnetotaxis at or above the class or phylum level, although the evolutionary trajectories at lower taxonomic ranks (e.g., within the class level) remain largely unstudied. Here we report the isolation, cultivation, and sequencing of a novel magnetotactic spirillum belonging to the genus Terasakiella (Terasakiella sp. strain SH-1) within the class Alphaproteobacteria. The complete genome sequence of Terasakiella sp. strain SH-1 revealed an unexpected duplication event of magnetosome genes within the mamAB operon, a group of genes essential for magnetosome biomineralization and magnetotaxis. Intriguingly, further comparative genomic analysis suggests that the duplication of mamAB genes is a common feature in the genomes of alphaproteobacterial MTB. Taken together, with the additional finding that gene duplication appears to have also occurred in some magnetotactic members of the Deltaproteobacteria, our results indicate that gene duplication plays an important role in the evolution of magnetotaxis in the Alphaproteobacteria and perhaps the domain Bacteria. IMPORTANCE A diversity of organisms can sense the geomagnetic field for the purpose of navigation. Magnetotactic bacteria are the most primitive magnetism-sensing organisms known thus far and represent an excellent model system for the study of the origin, evolution, and mechanism of microbial magnetoreception (or magnetotaxis). The present study is the first report focused on magnetosome gene cluster duplication in the Alphaproteobacteria, which suggests the important role of gene duplication in the evolution of magnetotaxis in the Alphaproteobacteria and perhaps the domain Bacteria. A novel scenario for the evolution of magnetotaxis in the Alphaproteobacteria is proposed and may provide new insights into evolution of magnetoreception of higher species.

Looking backwards to look forwards: the role of natural history in temperate reef ecology

2016 ◽  
Vol 67 (1) ◽  
pp. 1 ◽  
Author(s):  
S. J. Hawkins ◽  
N. Mieszkowska ◽  
L. B. Firth ◽  
K. Bohn ◽  
M. T. Burrows ◽  
...  
Keyword(s):  
Natural History ◽  
Evolutionary Biology ◽  
Temperate Reef ◽  
Molecular Approaches ◽  
Temperate Reefs ◽  
History Of Research ◽  
History Of ◽  
Meta Analyses ◽  
Rich History

Temperate reefs are superb tractable systems for testing hypotheses in ecology and evolutionary biology. Accordingly there is a rich history of research stretching back over 100 years, which has made major contributions to general ecological and evolutionary theory as well as providing better understanding of how littoral systems work by linking pattern with process. A brief resumé of the history of temperate reef ecology is provided to celebrate this rich heritage. As a community, temperate reef ecologists generally do well designed experiments and test well formulated hypotheses. Increasingly large datasets are being collected, collated and subjected to complex meta-analyses and used for modelling. These datasets do not happen spontaneously – the burgeoning subject of macroecology is possible only because of the efforts of dedicated natural historians whether it be observing birds, butterflies, or barnacles. High-quality natural history and old-fashioned field craft enable surveys or experiments to be stratified (i.e. replicates are replicates and not a random bit of rock) and lead to the generation of more insightful hypotheses. Modern molecular approaches have led to the discovery of cryptic species and provided phylogeographical insights, but natural history is still required to identify species in the field. We advocate a blend of modern approaches with old school skills and a fondness for temperate reefs in all their splendour.

Mating system and genetic polymorphism in populations of Secale cereale and S. vavilovii

1984 ◽  
Vol 26 (3) ◽  
pp. 308-317 ◽  
Author(s):  
M. Pérez De La Vega ◽  
R. W. Allard
Keyword(s):  
Mating System ◽  
Secale Cereale ◽  
Random Mating ◽  
Genetic Studies ◽  
Banding Patterns ◽  
Enzyme Systems ◽  
Incompatibility System ◽  
Secale Cereale L ◽  
Isozyme Polymorphism ◽  
Self Fertilization

Electrophoretic banding patterns were determined for nine enzyme systems (IPO, PGM, PGI, LAP, GOT, EST, PHOS, MDH, CPX) in four populations of Secale cereale L. from widely different geographical areas, and in one population of S. vavilovii Grossh. Secale cereale was found to be extensively variable and S. vavilovii invariant for these enzyme systems. Formal genetic studies of nine polymorphic banding zones in S. cereale revealed that each zone was under single locus control. Mating system studies based on these loci indicated that 8% of self-fertilization occurred under field conditions in a population of S. cereale, a species with a highly developed self-incompatibility system. Each population was characterized by fewer heterozygotes than expected in random mating populations. Genotypic and allelic frequencies were nearly identical in four populations of S. cereale, despite their diverse origins and different cytological characteristics.Key words: mating system, Secale, rye, isozyme polymorphism.

Flowering and mating system in hybridizing Carpobrotus (Aizoaceae) in coastal California

1998 ◽  
Vol 76 (7) ◽  
pp. 1165-1169 ◽  
Author(s):  
Montserrat Vilà ◽  
Ewald Weber ◽  
Carla M D'Antonio
Keyword(s):  
Mating System ◽  
Exotic Species ◽  
Seed Set ◽  
High Potential ◽  
Natural Hybridization ◽  
Pesticide Application ◽  
Hybrid Fitness ◽  
Carpobrotus Edulis ◽  
Self Fertilization ◽  
Corolla Diameter

Patterns of flowering and pollination visit of Carpobrotus spp. were examined to determine the hybridization potential between the introduced succulent perennial Carpobrotus edulis and its native congener, Carpobrotus chilensis, in coastal California. Both species flower from March to July and both are visited by the same Thysanoptera and Coleoptera taxa. Flowers from hybrid-appearing individuals were intermediate in corolla diameter. Emasculation and bagging experiments suggest that C. edulis and hybrid morphotypes have facultative agamospermia, whereas C. chilensis has facultative self-fertilization. Emasculated C. chilensis did not set seeds. Pesticide application and flower bagging suggest that 80% of seed set in self-pollinated C. chilensis flowers is mediated by thrips. Our results suggest that there is high potential for natural hybridization in Carpobrotus species in California and that Carpobrotus populations can persist without cross-pollination.Key words: Carpobrotus, exotic species, facultative agamospermia, hybrid fitness, invasion, pollination preference.

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