scholarly journals Evolutionary stability of jointly evolving traits in subdivided populations

2016 ◽  
Author(s):  
Charles Mullon ◽  
Laurent Keller ◽  
Laurent Lehmann
Keyword(s):  
Quantitative Traits ◽  
Evolutionary Stability ◽  
Population Subdivision ◽  
Multiple Traits ◽  
Diversifying Selection ◽  
Fitness Effects ◽  
Subdivided Populations ◽  
Limited Dispersal ◽  
Indirect Fitness ◽  
Dispersal Cost

The evolutionary stability of quantitative traits depends on whether a population can resist invasion by any mutant. While uninvadability is well understood in well-mixed populations, it is much less so in subdivided populations when multiple traits evolve jointly. Here, we investigate whether a spatially subdivided population at a monomorphic equilibrium for multiple traits can withstand invasion by any mutant, or is subject to diversifying selection. Our model also explores the among traits correlations arising from diversifying selection and how they depend on relatedness due to limited dispersal. We find that selection favours a positive (negative) correlation between two traits, when the selective effects of one trait on relatedness is positively (negatively) correlated to the indirect fitness effects of the other trait. We study the evolution of traits for which this matters: dispersal that decreases relatedness, and helping that has positive indirect fitness effects. We find that when dispersal cost is low and the benefits of helping accelerate faster than its costs, selection leads to the coexistence of mobile defectors and sessile helpers. Otherwise, the population evolves to a monomorphic state with intermediate helping and dispersal. Overall, our results highlight the importance of population subdivision for evolutionary stability and correlations among traits.

scholarly journals Dispersal alters the nature and scope of sexually antagonistic variation

2020 ◽  
Author(s):  
Ewan O Flintham ◽  
Vincent Savolainen ◽  
Charles Mullon
Keyword(s):  
Genetic Variation ◽  
Balancing Selection ◽  
Sexual Antagonism ◽  
Previous Theory ◽  
Fitness Effects ◽  
Kin Competition ◽  
Spatial Subdivision ◽  
Subdivided Populations ◽  
Limited Dispersal ◽  
Intralocus Conflict

AbstractIntra-locus sexual conflict, or sexual antagonism, occurs when alleles have opposing fitness effects in the two sexes. Previous theory suggests that sexual antagonism is a driver of genetic variation by generating balancing selection. However, these studies assume that populations are well-mixed, neglecting the effects of spatial subdivision. Here we use mathematical modelling to show that limited dispersal can fundamentally change evolution at sexually antagonistic autosomal and X-linked loci due to inbreeding and sex-specific kin competition. We find that if the sexes disperse at different rates, kin competition within the philopatric sex biases intralocus conflict in favour of the more dispersive sex. Furthermore, kin competition diminishes the strength of balancing selection relative to genetic drift, reducing genetic variation in small subdivided populations. Meanwhile, by decreasing heterozygosity, inbreeding reduces the scope for sexually antagonistic polymorphism due to non-additive allelic effects, and this occurs to a greater extent on the X-chromosome than autosomes. Overall, our results demonstrate that spatial structure is an important factor in predicting where to expect sexually antagonistic alleles. We suggest that observed interspecific and intragenomic variation in sexual antagonism may be explained by sex-specific dispersal ecology and demography.

scholarly journals A quantitative genetics approach to the evolution of phenotypic (co)variance under limited dispersal, with an application to socially synergistic traits

2018 ◽  
Author(s):  
Charles Mullon ◽  
Laurent Lehmann
Keyword(s):  
Quantitative Genetics ◽  
Darwinian Evolution ◽  
Classical Dynamics ◽  
Multiple Traits ◽  
Fitness Effects ◽  
Correlational Selection ◽  
Social Traits ◽  
Trait Distribution ◽  
Limited Dispersal ◽  
Specific Variation

AbstractDarwinian evolution consists of the gradual transformation of heritable quantitative traits due to natural selection and the input of random variation by mutation. Here, we use a quantitative genetics approach to investigate the coevolution of multiple traits under selection, mutation, and limited dispersal. We track the dynamics of trait means and variance-covariances between traits that experience frequency-dependent selection. Assuming a multivariate-normal trait distribution, we recover classical dynamics of quantitative genetics, as well as stability and evolutionary branching conditions of invasion analyses, except that due to limited dispersal, selection depends on indirect fitness effects and relatedness. In particular, correlational selection that associates different traits within-individuals depends on the fitness effects of such associations between-individuals. These kin selection effects can be as relevant as pleiotropy for correlation between traits. We illustrate this with an example of the coevolution of two social traits whose association within-individual is costly but synergistically beneficial between-individuals. As dispersal becomes limited and relatedness increases, associations between-traits between-individuals become increasingly targeted by correlational selection. Consequently, the trait distribution goes from being bimodal with a negative correlation under panmixia to unimodal with a positive correlation under limited dispersal. More broadly, our approach can help understand the evolution of intra-specific variation.

scholarly journals Identification of Associations between SSR Markers and Quantitative Traits of Maize (Zea mays L.)

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 182
Author(s):  
Jan Bocianowski ◽  
Kamila Nowosad ◽  
Barbara Wróbel ◽  
Piotr Szulc
Keyword(s):  
Zea Mays ◽  
Ssr Markers ◽  
Marker Assisted Selection ◽  
Quantitative Traits ◽  
Zea Mays L ◽  
Fresh Weight ◽  
Multiple Traits ◽  
Good Tool ◽  
Maize Varieties ◽  
Hybrid Maize

Microsatellite or simple sequence repeat (SSR) markers have wide applicability for genetic analysis in crop plant improvement strategies. Marker-assisted selection is an important tool for plant breeders to increase the efficiency of a breeding process, especially for multigenic traits, highly influenced by the environment. In this paper, the relationships between SSR markers and 26 quantitative traits of hybrid maize varieties (Zea mays L.) were analyzed. Association analyses were performed based on 30 SSR primers in a set of thirteen hybrid maize varieties. A total of 112 SSR markers were detected in these genotypes. The number of alleles per locus ranged from 1 to 17, with the average number of alleles per locus equal to 3.7. The number of molecular markers associated with observed traits ranged from 1 (for the number of kernels in row, ears weight and fresh weight of one plant) to 14 (for damage of maize caused by P. nubilalis) in 2016 as well as from 1 (for soil plant analysis development—SPAD, the number of grains in ear and fresh weight of one plant) to 12 (for carotenoids content) in 2017. The sum of statistically significant associations between SSR markers and at least one trait was equal to one hundred sixty in 2016 as well as one hundred twenty-five in 2017. Marker trait associations (MTAs) were found on the basis of regression analysis. The proportion of the total phenotypic variances of individual traits explained by the marker ranged from 24.4% to 77.7% in the first year of study and from 24.3% to 77.9% in 2017. Twenty-two SSR markers performed a significant effect on at least one tested trait in both years of experiment. The three markers (phi021/4, phi036/3, and phi061/2) can be a good tool in marker-assisted selection because they allow simultaneous selection for multiple traits in both years of study, such as the number of kernels in row and the number of grains in ear (phi021/4), the number of plant after germination, the number of plants before harvest, and the number of ears (phi036/3), as well as moisture of grain and length of ears (phi061/2).

scholarly journals Understanding the evolution of interspecies interactions in microbial communities

2020 ◽  
Vol 375 (1798) ◽  
pp. 20190256 ◽  
Author(s):  
Florien A. Gorter ◽  
Michael Manhart ◽  
Martin Ackermann
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Interaction Strength ◽  
Quantitative Model ◽  
Systematic Effect ◽  
Interspecies Interactions ◽  
Fitness Effects ◽  
Indirect Fitness ◽  
Beneficial Traits ◽  
Selection Of

Microbial communities are complex multi-species assemblages that are characterized by a multitude of interspecies interactions, which can range from mutualism to competition. The overall sign and strength of interspecies interactions have important consequences for emergent community-level properties such as productivity and stability. It is not well understood how interspecies interactions change over evolutionary timescales. Here, we review the empirical evidence that evolution is an important driver of microbial community properties and dynamics on timescales that have traditionally been regarded as purely ecological. Next, we briefly discuss different modelling approaches to study evolution of communities, emphasizing the similarities and differences between evolutionary and ecological perspectives. We then propose a simple conceptual model for the evolution of interspecies interactions in communities. Specifically, we propose that to understand the evolution of interspecies interactions, it is important to distinguish between direct and indirect fitness effects of a mutation. We predict that in well-mixed environments, traits will be selected exclusively for their direct fitness effects, while in spatially structured environments, traits may also be selected for their indirect fitness effects. Selection of indirectly beneficial traits should result in an increase in interaction strength over time, while selection of directly beneficial traits should not have such a systematic effect. We tested our intuitions using a simple quantitative model and found support for our hypotheses. The next step will be to test these hypotheses experimentally and provide input for a more refined version of the model in turn, thus closing the scientific cycle of models and experiments. This article is part of the theme issue ‘Conceptual challenges in microbial community ecology’.

scholarly journals Male relatedness and familiarity are required to modulate male-induced harm to females in Drosophila

2017 ◽  
Vol 284 (1860) ◽  
pp. 20170441 ◽  
Author(s):  
Sally Le Page ◽  
Irem Sepil ◽  
Ewan Flintham ◽  
Tommaso Pizzari ◽  
Pau Carazo ◽  
...  
Keyword(s):  
Potential Role ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Kin Recognition ◽  
Female Reproduction ◽  
Fitness Effects ◽  
Inclusive Fitness Theory ◽  
Indirect Fitness ◽  
Female Lifespan

Males compete over mating and fertilization, and often harm females in the process. Inclusive fitness theory predicts that increasing relatedness within groups of males may relax competition and discourage male harm of females as males gain indirect benefits. Recent studies in Drosophila melanogaster are consistent with these predictions, and have found that within-group male relatedness increases female fitness, though others have found no effects. Importantly, these studies did not fully disentangle male genetic relatedness from larval familiarity, so the extent to which modulation of harm to females is explained by male familiarity remains unclear. Here we performed a fully factorial design, isolating the effects of male relatedness and larval familiarity on female harm. While we found no differences in male courtship or aggression, there was a significant interaction between male genetic relatedness and familiarity on female reproduction and survival. Relatedness among males increased female lifespan, reproductive lifespan and overall reproductive success, but only when males were familiar. By showing that both male relatedness and larval familiarity are required to modulate female harm, these findings reconcile previous studies, shedding light on the potential role of indirect fitness effects on sexual conflict and the mechanisms underpinning kin recognition in fly populations.

scholarly journals Breakdown of gametophytic self-incompatibility in subdivided populations

2018 ◽  
Author(s):  
Thomas Brom ◽  
Vincent Castric ◽  
Sylvain Billiard
Keyword(s):  
Inbreeding Depression ◽  
Natural Populations ◽  
Simulation Models ◽  
Population Subdivision ◽  
Self Incompatibility ◽  
S Locus ◽  
Isolated Populations ◽  
Data Accessibility ◽  
Local Diversity ◽  
Subdivided Populations

AbstractMany hermaphroditic flowering plants species possess a genetic self-incompatibility (SI) system that prevents self-fertilization and is typically controlled by a single multiallelic locus, the S-locus. The conditions under which SI can be stably maintained in single isolated populations are well known and depend chiefly on the level of inbreeding depression and the number of SI alleles segregating at the S-locus. However, while both the number of SI alleles and the level of inbreeding depression are potentially affected by population subdivision, the conditions for the maintenance of SI in subdivided populations remain to be studied. In this paper, we combine analytical predictions and two different individual-based simulation models to show that population subdivision can severely compromise the maintenance of SI. Under the conditions we explored, this effect is mainly driven by the decrease of the local diversity of SI alleles rather than by a change in the dynamics of inbreeding depression. We discuss the implications of our results for the interpretation of empirical data on the loss of SI in natural populations.Data accessibility statementNo data to be archived

scholarly journals Mutations and quantitative genetic variation: lessons from Drosophila

2010 ◽  
Vol 365 (1544) ◽  
pp. 1229-1239 ◽  
Author(s):  
Trudy F. C. Mackay
Keyword(s):  
Genetic Variation ◽  
Quantitative Traits ◽  
Genetic Correlations ◽  
Intermediate Frequency ◽  
Mutation Rates ◽  
Stabilizing Selection ◽  
Detailed Knowledge ◽  
Multiple Traits ◽  
Association Analyses ◽  
Specific Effects

A central issue in evolutionary quantitative genetics is to understand how genetic variation for quantitative traits is maintained in natural populations. Estimates of genetic variation and of genetic correlations and pleiotropy among multiple traits, inbreeding depression, mutation rates for fitness and quantitative traits and of the strength and nature of selection are all required to evaluate theoretical models of the maintenance of genetic variation. Studies in Drosophila melanogaster have shown that a substantial fraction of segregating variation for fitness-related traits in Drosophila is due to rare deleterious alleles maintained by mutation–selection balance, with a smaller but significant fraction attributable to intermediate frequency alleles maintained by alleles with antagonistic pleiotropic effects, and late-age-specific effects. However, the nature of segregating variation for traits under stabilizing selection is less clear and requires more detailed knowledge of the loci, mutation rates, allelic effects and frequencies of molecular polymorphisms affecting variation in suites of pleiotropically connected traits. Recent studies in D. melanogaster have revealed unexpectedly complex genetic architectures of many quantitative traits, with large numbers of pleiotropic genes and alleles with sex-, environment- and genetic background-specific effects. Future genome wide association analyses of many quantitative traits on a common panel of fully sequenced Drosophila strains will provide much needed empirical data on the molecular genetic basis of quantitative traits.

scholarly journals A sampling theory of selectively neutral alleles in a subdivided population.

Genetics ◽  
1988 ◽  
Vol 119 (3) ◽  
pp. 721-729
Author(s):  
E R Tillier ◽  
G B Golding
Keyword(s):  
Population Structure ◽  
Population Subdivision ◽  
Continuous Approximation ◽  
Sample Distribution ◽  
Migration Rates ◽  
Practical Possibility ◽  
Structured Population ◽  
Subdivided Population ◽  
Subdivided Populations ◽  
Actual Size

Abstract Ewens' sampling distribution is investigated for a structured population. Samples are assumed to be taken from a single subpopulation that exchanges migrants with other subpopulations. A complete description of the probability distribution for such samples is not a practical possibility but an equilibrium approximation can be found. This approximation extracts the information necessary for constructing a continuous approximation to the complete distribution using known values of the distribution and its derivatives in randomly mating populations. It is shown that this approximation is as complete a description of a single biologically realistic subpopulation as is possible given standard uncertainties about the actual size of the migration rates, relative sizes of each of the subpopulations and other factors that might affect the genetic structure of a subpopulation. Any further information must be gained at the expense of generality. This approximation is used to investigate the effect of population subdivision on Watterson's test of neutrality. It is known that the infinite allele, sample distribution is independent of mutation rate when made conditional on the number of alleles in the sample. It is shown that the conditional, infinite allele, sample distribution from this approximation is also independent of population structure and hence Watterson's test is still approximately valid for subdivided populations.

Genetic Analysis of Sunflower Domestication

Genetics ◽  
2002 ◽  
Vol 161 (3) ◽  
pp. 1257-1267 ◽  
Author(s):  
John M Burke ◽  
Shunxue Tang ◽  
Steven J Knapp ◽  
Loren H Rieseberg
Keyword(s):  
Quantitative Traits ◽  
Mapping Population ◽  
Interval Mapping ◽  
Phenotypic Variance ◽  
Linkage Groups ◽  
Multiple Traits ◽  
Wild Progenitor ◽  
Phenotypic Differences ◽  
Selection For ◽  
Major Qtl

Abstract Quantitative trait loci (QTL) controlling phenotypic differences between cultivated sunflower and its wild progenitor were investigated in an F3 mapping population. Composite interval mapping revealed the presence of 78 QTL affecting the 18 quantitative traits of interest, with 2–10 QTL per trait. Each QTL explained 3.0–68.0% of the phenotypic variance, although only 4 (corresponding to 3 of 18 traits) had effects >25%. Overall, 51 of the 78 QTL produced phenotypic effects in the expected direction, and for 13 of 18 traits the majority of QTL had the expected effect. Despite being distributed across 15 of the 17 linkage groups, there was a substantial amount of clustering among QTL controlling different traits. In several cases, regions influencing multiple traits harbored QTL with antagonistic effects, producing a cultivar-like phenotype for some traits and a wild-like phenotype for others. On the basis of the directionality of QTL, strong directional selection for increased achene size appears to have played a central role in sunflower domestication. None of the other traits show similar evidence of selection. The occurrence of numerous wild alleles with cultivar-like effects, combined with the lack of major QTL, suggests that sunflower was readily domesticated.

scholarly journals Patterns of Inbreeding Depression and Architecture of the Load in Subdivided Populations

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 2193-2212 ◽  
Author(s):  
Sylvain Glémin ◽  
Joëlle Ronfort ◽  
Thomas Bataillon
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Inbreeding Depression ◽  
Local Population ◽  
Population Subdivision ◽  
Deleterious Mutations ◽  
Effective Population ◽  
Subdivided Populations ◽  
And Migration ◽  
Insight Into

AbstractInbreeding depression is a general phenomenon that is due mainly to recessive deleterious mutations, the so-called mutation load. It has been much studied theoretically. However, until very recently, population structure has not been taken into account, even though it can be an important factor in the evolution of populations. Population subdivision modifies the dynamics of deleterious mutations because the outcome of selection depends on processes both within populations (selection and drift) and between populations (migration). Here, we present a general model that permits us to gain insight into patterns of inbreeding depression, heterosis, and the load in subdivided populations. We show that they can be interpreted with reference to single-population theory, using an appropriate local effective population size that integrates the effects of drift, selection, and migration. We term this the “effective population size of selection” (NeS). For the infinite island model, for example, it is equal to NeS=N(1+m∕hs), where N is the local population size, m the migration rate, and h and s the dominance and selection coefficients of deleterious mutation. Our results have implications for the estimation and interpretation of inbreeding depression in subdivided populations, especially regarding conservation issues. We also discuss the possible effects of migration and subdivision on the evolution of mating systems.

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