scholarly journals Polymorphism at a mimicry supergene maintained by opposing frequency-dependent selection pressures

2017 ◽  
Vol 114 (31) ◽  
pp. 8325-8329 ◽  
Author(s):  
Mathieu Chouteau ◽  
Violaine Llaurens ◽  
Florence Piron-Prunier ◽  
Mathieu Joron
Keyword(s):  
Evolutionary Biology ◽  
Natural Populations ◽  
Mate Preferences ◽  
Visual Signals ◽  
Wing Pattern ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Conservation Medicine ◽  
Local Diversity ◽  
Adaptive Diversity

Explaining the maintenance of adaptive diversity within populations is a long-standing goal in evolutionary biology, with important implications for conservation, medicine, and agriculture. Adaptation often leads to the fixation of beneficial alleles, and therefore it erodes local diversity so that understanding the coexistence of multiple adaptive phenotypes requires deciphering the ecological mechanisms that determine their respective benefits. Here, we show how antagonistic frequency-dependent selection (FDS), generated by natural and sexual selection acting on the same trait, maintains mimicry polymorphism in the toxic butterfly Heliconius numata. Positive FDS imposed by predators on mimetic signals favors the fixation of the most abundant and best-protected wing-pattern morph, thereby limiting polymorphism. However, by using mate-choice experiments, we reveal disassortative mate preferences of the different wing-pattern morphs. The resulting negative FDS on wing-pattern alleles is consistent with the excess of heterozygote genotypes at the supergene locus controlling wing-pattern variation in natural populations of H. numata. The combined effect of positive and negative FDS on visual signals is sufficient to maintain a diversity of morphs displaying accurate mimicry with other local prey, although some of the forms only provide moderate protection against predators. Our findings help understand how alternative adaptive phenotypes can be maintained within populations and emphasize the need to investigate interactions between selective pressures in other cases of puzzling adaptive polymorphism.

scholarly journals Negative frequency-dependent selection is frequently confounding

2017 ◽  
Author(s):  
Dustin Brisson
Keyword(s):  
Genetic Diversity ◽  
Evolutionary Biology ◽  
Balancing Selection ◽  
Natural Populations ◽  
Research Progress ◽  
Selective Force ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Negative Frequency Dependent Selection ◽  
Peer Community

AbstractThis preprint has been reviewed and recommended by Peer Community in Evolutionary Biology (http://dx.doi.org/10.24072/pci.evolbiol.100024).The existence of persistent genetic variation within natural populations presents an evolutionary problem as natural selection and genetic drift tend to erode genetic diversity. Models of balancing selection were developed to account for the high and sometimes extreme levels of polymorphism found in many natural populations. Negative frequency-dependent selection may be the most powerful selective force maintaining balanced natural polymorphisms but it is also commonly misinterpreted. The aim of this review is to clarify the processes underlying negative frequency-dependent selection, describe classes of natural polymorphisms that can and cannot result from these processes, and discuss observational and experimental data that can aid in accurately identifying the processes that generated or are maintain diversity in nature. Finally, I consider the importance of accurately describing the processes affecting genetic diversity within populations as it relates to research progress.

scholarly journals Causation without correlation: parasite-mediated frequency-dependent selection and infection prevalence

2021 ◽  
Author(s):  
Curtis M Lively ◽  
Julie Xu ◽  
Frida Ben-Ami
Keyword(s):  
Genetic Diversity ◽  
Natural Populations ◽  
Infection Prevalence ◽  
Strong Positive Correlation ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Host Diversity ◽  
Host Genetic ◽  
Host Parasite

Parasite-mediated selection is thought to maintain host genetic diversity for resistance. We might thus expect to find a strong positive correlation between host genetic diversity and infection prevalence across natural populations. Here we used computer simulations to examine host-parasite coevolution in 20 simi-isolated clonal populations across a broad range of values for both parasite virulence and parasite fecundity. We found that the correlation between host genetic diversity and infection prevalence can be significantly positive for intermediate values of parasite virulence and fecundity. But the correlation can also be weak and statistically non-significant, even when parasite-mediated frequency-dependent selection is the sole force maintaining host diversity. Hence correlational analyses of field populations, while useful, might underestimate the role of parasites in maintaining host diversity.

scholarly journals Dominant words rise to the top by positive frequency-dependent selection

2019 ◽  
Vol 116 (15) ◽  
pp. 7397-7402 ◽  
Author(s):  
Mark Pagel ◽  
Mark Beaumont ◽  
Andrew Meade ◽  
Annemarie Verkerk ◽  
Andreea Calude
Keyword(s):  
Natural Populations ◽  
Word Choice ◽  
Random Drift ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Neutral Drift ◽  
Word Use ◽  
New Words ◽  
Core Lexicon ◽  
Positive Frequency

A puzzle of language is how speakers come to use the same words for particular meanings, given that there are often many competing alternatives (e.g., “sofa,” “couch,” “settee”), and there is seldom a necessary connection between a word and its meaning. The well-known process of random drift—roughly corresponding in this context to “say what you hear”—can cause the frequencies of alternative words to fluctuate over time, and it is even possible for one of the words to replace all others, without any form of selection being involved. However, is drift alone an adequate explanation of a shared vocabulary? Darwin thought not. Here, we apply models of neutral drift, directional selection, and positive frequency-dependent selection to explain over 417,000 word-use choices for 418 meanings in two natural populations of speakers. We find that neutral drift does not in general explain word use. Instead, some form of selection governs word choice in over 91% of the meanings we studied. In cases where one word dominates all others for a particular meaning—such as is typical of the words in the core lexicon of a language—word choice is guided by positive frequency-dependent selection—a bias that makes speakers disproportionately likely to use the words that most others use. This bias grants an increasing advantage to the common form as it becomes more popular and provides a mechanism to explain how a shared vocabulary can spontaneously self-organize and then be maintained for centuries or even millennia, despite new words continually entering the lexicon.

scholarly journals Consistent female preference for rare and unfamiliar male color patterns in wild guppy populations

2019 ◽  
Vol 30 (6) ◽  
pp. 1672-1681 ◽  
Author(s):  
Jennifer J Valvo ◽  
F Helen Rodd ◽  
Kimberly A Hughes
Keyword(s):  
Genetic Variation ◽  
Poecilia Reticulata ◽  
Natural Populations ◽  
Female Preference ◽  
Male Mating ◽  
Color Patterns ◽  
High Genetic Diversity ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Negative Frequency Dependent Selection

Abstract How genetic variation is maintained in ecologically important traits is a central question in evolutionary biology. Male Trinidadian guppies, Poecilia reticulata, exhibit high genetic diversity in color patterns within populations, and field and laboratory studies implicate negative frequency-dependent selection in maintaining this variation. However, behavioral and ecological processes that mediate this selection in natural populations are poorly understood. We evaluated female mate preference in 11 natural guppy populations, including paired populations from high- and low-predation habitats, to determine if this behavior is responsible for negative frequency-dependent selection and to evaluate its prevalence in nature. Females directed significantly more attention to males with rare and unfamiliar color patterns than to males with common patterns. Female attention also increased with the area of male orange coloration, but this preference was independent of the preference for rare and unfamiliar patterns. We also found an overall effect of predation regime; females from high-predation populations directed more attention toward males than those from low-predation populations. Again, however, the habitat-linked preference was statistically independent from the preference for rare and unfamiliar patterns. Because previous research indicates that female attention to males predicts male mating success, we conclude that the prevalence of female preference for males with rare and unfamiliar color patterns across many natural populations supports the hypothesis that female preference is an important process underlying the maintenance of high genetic variation in guppy color patterns.

The evolution of genetic diversity

1979 ◽  
Vol 205 (1161) ◽  
pp. 453-474 ◽  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Enzyme Kinetics ◽  
Genetic Control ◽  
Molecular Level ◽  
Natural Populations ◽  
Morphological Characters ◽  
Continuous Variation ◽  
Frequency Dependent ◽  
Frequency Dependent Selection

The existence within natural populations of large amounts of genetic variation in molecules and morphology presents an evolutionary problem. The ‘neutralist’ solution to this problem, that the variation is usually unimportant to the organisms displaying it, has now lost much of its strength. Interpretations that assume widespread heterozygous advantage also face serious difficulties. A resolution is possible in terms of frequency-dependent selection by predators, parasites and competitors. The evidence for pervasive frequency-dependent selection is now very strong. It appears to follow naturally from the behaviour of predators, from the evolutionary lability of parasites, from the ecology of competition and, at the molecular level, from the phenomena of enzyme kinetics. Such selection can explain the maintenance not only of conventional polymorphism but also of continuous variation in both molecular and morphological characters. It can account for the occurrence of diversity within groups of haploid and self-fertilizing organisms, and for the evolution of differences between individuals in their systems of genetic control.

scholarly journals Preserving genes: a model of the maintenance of genetic variation in a metapopulation under frequency-dependent selection

1995 ◽  
Vol 65 (3) ◽  
pp. 175-191 ◽  
Author(s):  
Olivia P. Judson
Keyword(s):  
Genetic Variation ◽  
Natural Populations ◽  
Practical Interest ◽  
Strong Interactions ◽  
Population Subdivision ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Maintenance Of Sex ◽  
Negative Frequency Dependent Selection ◽  
Asexual Populations

SummaryUnderstanding how genetic variability is maintained in natural populations is of both theoretical and practical interest. In particular, the subdivision of populations into demes linked by low levels of migration has been suggested to play an important role. But the maintenance of genetic variation in populations is also often linked to the maintenance of sexual reproduction: any force that acts to maintain sex should also act to maintain variation. One theory for the maintenance of sex, the Red Queen, states that sex and variation are maintained by antagonistic coevolutionary interactions – especially those between hosts and their harmful parasites – that give rise to negative frequency-dependent selection. In this paper I present a model to examine the relationships between population subdivision, negative frequency-dependent selection due to parasites, the maintenance of sex, and the preservation of alleles from fixation. The results show strong interactions between migration rates, negative frequency-dependent selection, and the maintenance of variability for sexual and asexual populations.

scholarly journals Frequency-dependent success of aggressive mimics in a cleaning symbiosis

2005 ◽  
Vol 272 (1581) ◽  
pp. 2635-2639 ◽  
Author(s):  
Karen L Cheney ◽  
Isabelle M Côté
Keyword(s):  
Coral Reef ◽  
Natural Populations ◽  
Reef Fishes ◽  
Coral Reef Fishes ◽  
Cleaning Symbiosis ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Labroides Dimidiatus ◽  
Aggressive Mimicry

Batesian mimics—palatable organisms that resemble unpalatable ones—are usually maintained in populations by frequency-dependent selection. We tested whether this mechanism was also responsible for the maintenance of aggressive mimicry in natural populations of coral reef fishes. The attack success of bluestriped fangblennies ( Plagiotremus rhinorhynchos ), which mimic juvenile bluestreaked cleaner wrasses ( Labroides dimidiatus ) in colour but tear flesh and scales from fishes instead of removing ectoparasites, was frequency-dependent, increasing as mimics became rarer relative to their model. However, cleaner mimics were also more successful on reefs with higher densities of potential victims, perhaps because a dilution-like effect creates few opportunities for potential victims to learn to avoid mimics. Further studies should reveal whether this second mechanism is specific to aggressive mimicry.

Adaptive Diversification (MPB-48)

2011 ◽  
Author(s):  
Michael Doebeli
Keyword(s):  
Evolutionary Biology ◽  
Biological Diversity ◽  
Adaptive Dynamics ◽  
Theoretical Treatment ◽  
Mathematical Framework ◽  
Evolutionary Branching ◽  
Rare Type ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Adaptive Diversification

Understanding the mechanisms driving biological diversity remains a central problem in ecology and evolutionary biology. Traditional explanations assume that differences in selection pressures lead to different adaptations in geographically separated locations. This book takes a different approach and explores adaptive diversification—diversification rooted in ecological interactions and frequency-dependent selection. In any ecosystem, birth and death rates of individuals are affected by interactions with other individuals. What is an advantageous phenotype therefore depends on the phenotype of other individuals, and it may often be best to be ecologically different from the majority phenotype. Such rare-type advantage is a hallmark of frequency-dependent selection and opens the scope for processes of diversification that require ecological contact rather than geographical isolation. This book investigates adaptive diversification using the mathematical framework of adaptive dynamics. Evolutionary branching is a paradigmatic feature of adaptive dynamics that serves as a basic metaphor for adaptive diversification, and the book explores the scope of evolutionary branching in many different ecological scenarios, including models of coevolution, cooperation, and cultural evolution. It also uses alternative modeling approaches. Stochastic, individual-based models are particularly useful for studying adaptive speciation in sexual populations, and partial differential equation models confirm the pervasiveness of adaptive diversification. Showing that frequency-dependent interactions are an important driver of biological diversity, the book provides a comprehensive theoretical treatment of adaptive diversification.

scholarly journals Two modes of balancing selection in Drosophila melanogaster: overcompensation and overdominance.

Genetics ◽  
1991 ◽  
Vol 128 (2) ◽  
pp. 381-391
Author(s):  
T X Peng ◽  
A Moya ◽  
F J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Balancing Selection ◽  
Natural Populations ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Designed Experiments ◽  
Two Temperatures ◽  
Limiting Resources ◽  
Uniform Population

Abstract Overdominance is often invoked to account for the extensive polymorphisms found in natural populations of organisms; overcompensation, however, may be equally or more important. Overcompensation occurs when limiting resources are better exploited by a genetically mixed than by a uniform population, and is often causally related to frequency-dependent selection. We have designed experiments to test whether overcompensation occurs in Drosophila melanogaster, using the Sod locus as a marker. Tests are made at each of two densities and two temperatures for cultures with desired genetic compositions. Both temperature and density have statistically significant effects on the per-female productivity of the cultures. More important, there are strong effects due to overcompensation. Cultures that are more polymorphic are also more productive than less polymorphic ones even when the level of individual heterozygosity is the same in all. There is also overdominance for the Sod locus: the heterozygotes are more productive than either homozygote at every temperature and density, and the differences are statistically significant in several cases. These results corroborate previous studies showing that overdominance may contribute to the maintenance of the Sod polymorphisms. Moreover, our results indicate that the significance of overcompensation as a mechanism to account for polymorphism in natural populations deserves further investigation.

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