scholarly journals Environmental unpredictability and inbreeding depression select for mixed dispersal syndromes

2015 ◽  
Author(s):  
Jorge Hidalgo ◽  
Rafael Rubio de Casas ◽  
Miguel A. Munoz
Keyword(s):  
Inbreeding Depression ◽  
Mixed Strategies ◽  
Dispersal Syndromes ◽  
Unpredictable Environments ◽  
High Dispersal ◽  
Environmental Unpredictability ◽  
Close Relatives ◽  
Single Phenotype ◽  
Evolutionarily Stable ◽  
Mathematical And Computational Modeling

Mixed dispersal syndromes have historically been regarded as bet-hedging mechanisms that enhance survival in unpredictable environments, ensuring that some propagules stay in the maternal environment while others can potentially colonize new sites. However, this entails paying the costs of both dispersal and non-dispersal. Propagules that disperse are likely to encounter unfavorable conditions for establishment, while non-dispersing propagules might form populations of close relatives burdened with inbreeding. Here, we investigate the conditions under which mixed dispersal syndromes emerge and are evolutionarily stable, taking into account the risks of both environmental unpredictability and inbreeding. Using mathematical and computational modeling we show that high dispersal propensity is favored whenever temporal environmental unpredictability is low and inbreeding depression high, whereas mixed dispersal syndromes are adaptive under conditions of high environmental unpredictability, but more particularly if also inbreeding depression is small. Although pure dispersers can be selected for under some circumstances, mixed dispersal provides the optimal strategy under most parameterizations of our models, indicating that this strategy is likely to be favored under a wide variety of conditions. Furthermore, populations exhibiting any single phenotype go inevitably extinct when environmental and genetic costs are high, whilst mixed strategies can maintain viable populations even under such conditions. Our models support the hypothesis that the interplay between inbreeding depression and environmental unpredictability shapes dispersal syndromes, often resulting in mixed strategies. Moreover, mixed dispersal seems to facilitate persistence whenever conditions are critical or nearly critical for survival.

Selection by parasites for clonal diversity and mixed mating

1994 ◽  
Vol 346 (1317) ◽  
pp. 271-281 ◽  
Keyword(s):  
Computer Simulations ◽  
Inbreeding Depression ◽  
Reproductive Strategies ◽  
Deleterious Mutation ◽  
Clonal Diversity ◽  
Evolutionary Stability ◽  
Mixed Mating ◽  
Dioecious Populations ◽  
Cross Fertilization ◽  
Evolutionarily Stable

On theoretical grounds, coevolutionary interactions with parasites can select for cross-fertilization, even when there is a twofold advantage gained by reproducing through uniparental means. The suspected advantage of cross-fertilization stems from the production of genetically rare offspring, which are expected to be more likely to escape infection by coevolving enemies. In the present study, we consider the effects that parasites have on parthenogenetic mutants in obligately sexual, dioecious populations. Computer simulations show that repeated mutation to parthenogenesis can lead to the accumulation of clones with different resistance genotypes, and that a moderately diverse set of clones could competitively exclude the ancestral sexual subpopulation. The simulations also show that, when there are reasonable rates of deleterious mutation, Muller’s ratchet combined with coevolutionary interactions with parasites can lead to the evolutionary stability of cross-fertilization. In addition, we consider the effects that parasites can have on the evolution of uniparental reproduction in cosexual populations. Strategy models show that parasites and inbreeding depression could interact to select for evolutionarily stable reproductive strategies that involve mixtures of selfed and outcrossed progeny.

Mutations, perturbations and evolutionarily stable strategies

1982 ◽  
Vol 19 (01) ◽  
pp. 204-209 ◽  
Author(s):  
W. G. S. Hines
Keyword(s):  
Population Model ◽  
Order Approximation ◽  
Population Diversity ◽  
Mixed Strategies ◽  
Competitive Strategies ◽  
Evolutionarily Stable Strategies ◽  
Third Order ◽  
Population Mean ◽  
Third Order Approximation ◽  
Evolutionarily Stable

The changes in diversity of competitive strategies in a Maynard Smith population model with mixed strategies are related to the changes in population mean strategy. The effects of slight mutations in strategy frequencies, and of slight perturbations of the contest payoff rules are then investigated, and found to increase and decrease diversity respectively (to a third-order approximation). A relation among mutational effects, payoff perturbation effects and stable population diversity is suggested.

Game theory and the evolution of behaviour

1979 ◽  
Vol 205 (1161) ◽  
pp. 475-488 ◽  
Keyword(s):  
Game Theory ◽  
Evolutionarily Stable Strategy ◽  
Field Studies ◽  
Mixed Strategies ◽  
Conditional Strategy ◽  
Stable Strategy ◽  
Frequency Dependent Selection ◽  
Contest Behaviour ◽  
Assessment Strategies ◽  
Evolutionarily Stable

How far can game theory account for the evolution of contest behaviour in animals? The first qualitative prediction of the theory was that symmetric contests in which escalation is expensive should lead to mixed strategies. As yet it is hard to say how far this is borne out, because of the difficulty of distinguishing a ‘mixed evolutionarily stable strategy’ maintained by frequency-dependent selection from a ‘pure conditional strategy'; the distinction is discussed in relation to several field studies. The second prediction was that if a contest is asymmetric (e. g. in ownership) then the asymmetry will be used as a conventional cue to settle it. This prediction has been well supported by observation. A third important issue is whether or not information about intentions is exchanged during contests. The significance of ‘assessment’ strategies is discussed.

scholarly journals Domestication reshaped the genetic basis of inbreeding depression in a maize landrace compared to its wild relative, teosinte

PLoS Genetics ◽  
2021 ◽  
Vol 17 (12) ◽  
pp. e1009797
Author(s):  
Luis Fernando Samayoa ◽  
Bode A. Olukolu ◽  
Chin Jian Yang ◽  
Qiuyue Chen ◽  
Markus G. Stetter ◽  
...  
Keyword(s):  
Inbreeding Depression ◽  
Rare Variants ◽  
Sequence Data ◽  
Genetic Load ◽  
Population History ◽  
Additional Contribution ◽  
Wild Relative ◽  
Small Individual ◽  
Maize Population ◽  
Close Relatives

Inbreeding depression is the reduction in fitness and vigor resulting from mating of close relatives observed in many plant and animal species. The extent to which the genetic load of mutations contributing to inbreeding depression is due to large-effect mutations versus variants with very small individual effects is unknown and may be affected by population history. We compared the effects of outcrossing and self-fertilization on 18 traits in a landrace population of maize, which underwent a population bottleneck during domestication, and a neighboring population of its wild relative teosinte. Inbreeding depression was greater in maize than teosinte for 15 of 18 traits, congruent with the greater segregating genetic load in the maize population that we predicted from sequence data. Parental breeding values were highly consistent between outcross and selfed offspring, indicating that additive effects determine most of the genetic value even in the presence of strong inbreeding depression. We developed a novel linkage scan to identify quantitative trait loci (QTL) representing large-effect rare variants carried by only a single parent, which were more important in teosinte than maize. Teosinte also carried more putative juvenile-acting lethal variants identified by segregation distortion. These results suggest a mixture of mostly polygenic, small-effect partially recessive effects in linkage disequilibrium underlying inbreeding depression, with an additional contribution from rare larger-effect variants that was more important in teosinte but depleted in maize following the domestication bottleneck. Purging associated with the maize domestication bottleneck may have selected against some large effect variants, but polygenic load is harder to purge and overall segregating mutational burden increased in maize compared to teosinte.

scholarly journals Associations of autozygosity with a broad range of human phenotypes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
David W Clark ◽  
Yukinori Okada ◽  
Kristjan H S Moore ◽  
Dan Mason ◽  
Nicola Pirastu ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Inbreeding Depression ◽  
Social Factors ◽  
Genetic Variants ◽  
Runs Of Homozygosity ◽  
Sibling Pairs ◽  
Full Sibling ◽  
Inbreeding Coefficients ◽  
Genomic Inbreeding ◽  
Close Relatives

Abstract In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (FROH) for >1.4 million individuals, we show that FROH is significantly associated (p < 0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: FROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44–66%] in the odds of having children. Finally, the effects of FROH are confirmed within full-sibling pairs, where the variation in FROH is independent of all environmental confounding.

scholarly journals Environmental unpredictability shapes glucocorticoid regulation across populations of tree swallows

2019 ◽  
Author(s):  
Cedric Zimmer ◽  
Conor C. Taff ◽  
Daniel R. Ardia ◽  
Alexandra P. Rose ◽  
David A. Aborn ◽  
...  
Keyword(s):  
Stress Response ◽  
Negative Feedback ◽  
Stress Responses ◽  
Environmental Gradient ◽  
Reproductive Value ◽  
Tree Swallows ◽  
Selective Pressures ◽  
Unpredictable Environments ◽  
Stress Responsiveness ◽  
Environmental Unpredictability

AbstractResponding appropriately to challenges is an important contributor to fitness. Variation in the regulation of glucocorticoid hormones, which mediate the phenotypic response to challenges, can therefore influence the ability to persist in a given environment. We compared stress responsiveness in four populations of tree swallows (Tachycineta bicolor) along an environmental gradient to evaluate support for different selective pressures in driving the evolution of glucocorticoid regulation. In accordance with the environmental unpredictability hypothesis, stronger stress responses were seen in more unpredictable environments. Contrary to the reproductive value hypothesis, the stress response was not lower in populations engaging in more valuable reproductive attempts. Populations with stronger stress responses also had stronger negative feedback, which supports a “mitigating” rather than a “magnifying” effect of negative feedback on stress responses. These results suggest that combining a robust stress response with strong negative feedback may be important for persisting in unpredictable or rapidly changing environments.

scholarly journals Domestication Reshaped the Genetic Basis of Inbreeding Depression in a Maize Landrace Compared to its Wild Relative, Teosinte

2021 ◽  
Author(s):  
James B. Holland ◽  
L.F. Samayoa ◽  
B.A. Olukolu ◽  
C.J. Yang ◽  
Q. Chen ◽  
...  
Keyword(s):  
Inbreeding Depression ◽  
Rare Variants ◽  
Sequence Data ◽  
Genetic Load ◽  
Population History ◽  
Additional Contribution ◽  
Wild Relative ◽  
Small Individual ◽  
Maize Population ◽  
Close Relatives

Inbreeding depression is the reduction in fitness and vigor resulting from mating of close relatives observed in many plant and animal species. The extent to which the genetic load of mutations contributing to inbreeding depression is due to rare large-effect variation versus potentially more common variants with very small individual effects is unknown and may be affected by population history. We compared the effects of outcrossing and self-fertilization on 18 traits in a landrace population of maize, which underwent a population bottleneck during domestication, and a neighboring population of its wild relative teosinte. Inbreeding depression was greater in maize than teosinte for 15 of 18 traits, congruent with the greater segregating genetic load predicted from sequence data in the maize population. For many traits - and more commonly in maize - genetic variation among self-fertilized families was less than expected based on additive and dominance variance estimated in outcrossed families, suggesting that a negative covariance between additive and homozygous dominance effects limits the variation available to selection under partial inbreeding. We identified quantitative trait loci (QTL) representing large-effect rare variants carried by only a single parent, which were more important in teosinte than maize. Teosinte also carried more putative juvenile-acting lethal variants identified by segregation distortion. These results suggest a mixture of mostly polygenic, small-effect recessive variation underlying inbreeding depression, with an additional contribution from rare larger-effect variants that was more important in teosinte but depleted in maize following to the domestication bottleneck. Purging associated with the maize domestication bottleneck may have selected against large effect variants, but polygenic load is harder to purge and segregating mutational burden increased in maize compared to teosinte.

Mutations, perturbations and evolutionarily stable strategies

1982 ◽  
Vol 19 (1) ◽  
pp. 204-209 ◽  
Author(s):  
W. G. S. Hines
Keyword(s):  
Population Model ◽  
Order Approximation ◽  
Population Diversity ◽  
Mixed Strategies ◽  
Competitive Strategies ◽  
Evolutionarily Stable Strategies ◽  
Third Order ◽  
Population Mean ◽  
Third Order Approximation ◽  
Evolutionarily Stable

The changes in diversity of competitive strategies in a Maynard Smith population model with mixed strategies are related to the changes in population mean strategy. The effects of slight mutations in strategy frequencies, and of slight perturbations of the contest payoff rules are then investigated, and found to increase and decrease diversity respectively (to a third-order approximation). A relation among mutational effects, payoff perturbation effects and stable population diversity is suggested.

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