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Andrew Pomiankowski - One of the best experts on this subject based on the ideXlab platform.

  • Meiotic Drive does not cause condition dependent reduction of the sexual ornament in stalk eyed flies
    Journal of Evolutionary Biology, 2021
    Co-Authors: Sam Ronan Finnegan, Matteo Mondani, Kevin Fowler, Andrew Pomiankowski
    Abstract:

    Meiotic Drive systems are associated with low frequency chromosomal inversions. These are expected to accumulate deleterious mutations due to reduced recombination and low effective population size. We test this prediction using the "sex-ratio" (SR) Meiotic Drive system of the Malaysian stalk-eyed fly Teleopsis dalmanni. SR is associated with a large inversion (or inversions) on the X chromosome. In particular, we study eyespan in males carrying the SR chromosome, as this trait is a highly exaggerated, sexually dimorphic trait, known to have heightened condition-dependent expression. Larvae were raised in low and high larval food stress environments. SR males showed reduced eyespan under the low and high stress treatments but there was no evidence of a condition-dependent decrease in eyespan under high stress. Similar but more complex patterns were observed for female eyespan, with evidence of additivity under low stress and heterosis under high stress. These results do not support the hypothesis that reduced sexual ornament size in Meiotic Drive males is due to a condition-dependent response to the putative increase in mutation load. Instead, reduced eyespan likely reflects compensatory resource allocation to different traits in response to Drive-mediated destruction of sperm.

  • Meiotic Drive does not cause condition‐dependent reduction of the sexual ornament in stalk‐eyed flies
    Journal of evolutionary biology, 2021
    Co-Authors: Sam Ronan Finnegan, Matteo Mondani, Kevin Fowler, Andrew Pomiankowski
    Abstract:

    Meiotic Drive systems are associated with low frequency chromosomal inversions. These are expected to accumulate deleterious mutations due to reduced recombination and low effective population size. We test this prediction using the "sex-ratio" (SR) Meiotic Drive system of the Malaysian stalk-eyed fly Teleopsis dalmanni. SR is associated with a large inversion (or inversions) on the X chromosome. In particular, we study eyespan in males carrying the SR chromosome, as this trait is a highly exaggerated, sexually dimorphic trait, known to have heightened condition-dependent expression. Larvae were raised in low and high larval food stress environments. SR males showed reduced eyespan under the low and high stress treatments but there was no evidence of a condition-dependent decrease in eyespan under high stress. Similar but more complex patterns were observed for female eyespan, with evidence of additivity under low stress and heterosis under high stress. These results do not support the hypothesis that reduced sexual ornament size in Meiotic Drive males is due to a condition-dependent response to the putative increase in mutation load. Instead, reduced eyespan likely reflects compensatory resource allocation to different traits in response to Drive-mediated destruction of sperm.

  • X-linked Meiotic Drive can boost population size and persistence.
    Genetics, 2020
    Co-Authors: Carl J. Mackintosh, Andrew Pomiankowski, Michael F. Scott
    Abstract:

    X-linked Meiotic Drivers cause X-bearing sperm to be produced in excess by male carriers, leading to female-biased sex ratios. Here, we find general conditions for the spread and fixation of X-linked alleles. Our conditions show that the spread of X-linked alleles depends on sex-specific selection and transmission rather than the time spent in each sex. Applying this logic to Meiotic Drive, we show that polymorphism is heavily dependent on sperm competition induced both by female and male mating behavior and the degree of compensation to gamete loss in the ejaculate size of Drive males. We extend these evolutionary models to investigate the demographic consequences of biased sex ratios. Our results suggest driving X-alleles that invade and reach polymorphism (or fix and do not bias segregation excessively) will boost population size and persistence time by increasing population productivity, demonstrating the potential for selfish genetic elements to move sex ratios closer to the population-level optimum. However, when the spread of Drive causes strong sex-ratio bias, it can lead to populations with so few males that females remain unmated, cannot produce offspring, and go extinct. This outcome is exacerbated when the male mating rate is low. We suggest that researchers should consider the potential for ecologically beneficial side effects of selfish genetic elements, especially in light of proposals to use Meiotic Drive for biological control.

  • X-linked Meiotic Drive boosts population size and persistence
    2020
    Co-Authors: Carl J. Mackintosh, Andrew Pomiankowski, Michael F. Scott
    Abstract:

    X-linked Meiotic Drivers cause X-bearing sperm to be produced in excess by male carriers, leading to female-biased sex ratios. Selection for these selfish sex chromosomes can lead to completely female populations, which cannot produce offspring and go extinct. However, at the population level, moderately female-biased sex ratios are optimal because relatively few males are required to fertilise all the females. We develop eco-evolutionary models for sex-linked Meiotic Drive alleles to investigate their full range of demographic effects. We find general conditions for the spread and fixation of X-Drivers, accounting for transmission bias and other factors associated with the spread of X-Drivers such as sperm competition and polyandry. Our results suggest driving X-alleles that do not reach fixation (or do not bias segregation excessively) will boost population sizes and persistence times by increasing population productivity, demonstrating the potential for selfish genetic elements to move sex ratios closer to the population-level optimum. We suggest that researchers should look beyond extinction risk and consider the potential for ecologically beneficial side effects of selfish genetic elements, especially in light of proposals to use Meiotic Drive for biological control.

  • Maintenance of Fertility in the Face of Meiotic Drive
    The American naturalist, 2020
    Co-Authors: Lara Meade, Sam Ronan Finnegan, Kevin Fowler, Ridhima Kad, Andrew Pomiankowski
    Abstract:

    AbstractSelfish genetic elements that gain a transmission advantage through the destruction of sperm have grave implications for Drive male fertility. In the X-linked Meiotic Drive system (SR) of a...

Gerald S. Wilkinson - One of the best experts on this subject based on the ideXlab platform.

  • Genetic linkage between a sexually selected trait and X chromosome Meiotic Drive
    Proceedings. Biological sciences, 2005
    Co-Authors: Philip M. Johns, L. Lareesa Wolfenbarger, Gerald S. Wilkinson
    Abstract:

    Previous studies on the stalk-eyed fly, Cyrtodiopsis dalmanni, have shown that males with long eye-stalks win contests and are preferred by females, and artificial selection on male relative eye span alters brood sexratios. Subsequent theory proposes that X-linked Meiotic Drive can catalyse the evolution of mate preferences when Drive is linked to ornament genes. Here we test this prediction by mapping Meiotic Drive and quantitative trait loci (QTL) for eye span. To map QTL we genotyped 24 microsatellite loci using 1228 F2 flies from two crosses between lines selected for long or short eye span. The crosses differed by presence or absence of a Drive X chromosome, X D , in the parental male. Linkage analysis reveals that X D dramatically reduces recombination between X and X D chromosomes. In the X D cross, half of the F2 males carried the Drive haplotype, produced partially elongated spermatids and female-biased broods, and had shorter eye span. The largest QTL mapped 1.3 cM from Drive on the X chromosome and explained 36% of the variation in male eye span while another QTL mapped to an autosomal region that suppresses Drive. These results indicate that selfish genetic elements that distort the sex-ratio can influence the evolution of exaggerated traits.

  • Meiotic Drive alters sperm competitive ability in stalk-eyed flies.
    Proceedings. Biological sciences, 2001
    Co-Authors: Gerald S. Wilkinson, Catherine L. Fry
    Abstract:

    Meiotic Drive results when sperm carrying a driving chromosome preferentially survive development. Meiotic Drive should therefore influence sperm competition because Drive males produce fewer sperm than non-Drive males. Whether Meiotic Drive also influences the competitive ability of sperm after ejaculation is unknown. Here we report the results from reciprocal crosses that are designed for estimating the sperm precedence of male stalk-eyed flies (Cyrtodiopsis whitei) with or without X-linked Meiotic Drive. We find that nearly half of all sex-ratio males, as compared with 14% of non-sex-ratio males, fail to produce young in a reciprocal cross. Furthermore, the proportion of progeny sired by a sex-ratio male in a female jointly inseminated by a non-sex-ratio male was less than expected from the number of sperm transferred. These effects are not due to differential sperm storage by females because, after a single mating with a sex-ratio male, all females stored sperm and because two sex-ratio males share paternity after jointly mating with a female. In addition to demonstrating a new mechanism of sperm competition, these results provide insight into the maintenance of sex-ratio polymorphisms. Sex-ratio males have less than one-half the fertility of non-sex-ratio males, as is required in order for frequency-dependent selection on males to produce a stable sex-ratio polymorphism.

  • Sperm development, age and sex chromosome Meiotic Drive in the stalk-eyed fly, Cyrtodiopsis whitei.
    Heredity, 2001
    Co-Authors: Gerald S. Wilkinson, Mara I Sanchez
    Abstract:

    The cytological basis of X chromosome Meiotic Drive or sex ratio (SR) has been reported for several species of Drosophila but not for other species. Here we describe how sperm development in the stalk-eyed fly, Cyrtodiopsis whitei, influences progeny sex proportion, in order to determine if a common developmental mechanism could cause Meiotic Drive in these distantly related taxa. Because age has been found to affect the degree of segregation distortion in some Drosophila, we tested flies from six to 26 weeks of age. We find that spermatocyst bundles in SR males frequently contain incompletely elongated spermatid nuclei independently of male age. Older males have, however, more spermatocyst bundles in their testes than younger males. Abnormal spermatid elongation affects male fertility since SR males produce 74% as many progeny per week as ST males. The proportion of spermatocyst bundles with improperly elongated spermatid nuclei explains 71% of the variation in progeny sex proportion. After reviewing the literature on sperm development and Meiotic Drive, we conclude that the cytological basis of Meiotic Drive in diopsids closely resembles Drosophila. Across species in both groups, the production of fertile males is associated with less than half of all spermatids not elongating normally in a spermatocyst bundle. We discuss the possibility that frequency-dependent selection on male fertility could stabilize the Drive polymorphism in these unusual flies.

  • Models of sex-ratio Meiotic Drive and sexual selection in stalk-eyed flies
    Genetical Research, 1999
    Co-Authors: Russell Lande, Gerald S. Wilkinson
    Abstract:

    Summary Hypertrophied sexually dimorphic eye stalks have evolved independently in several families of Diptera, with the eyespan of males exceeding their total body length in some species. These structures function in intermale contests for territories and in mate attraction, the classical mechanisms of sexual selection. In the family Diopsidae, species with extremely exaggerated eye stalks and marked sexual dimorphism in relative eyespan also usually have strongly female-biased sex ratios in nature caused by X-linked Meiotic Drive, whereas species with relatively small eye stalks have little or no sexual dimorphism, often lack Meiotic Drive and have even sex ratios. We investigate the possible connection between sexual selection and sex-ratio Meiotic Drive by analysing a three-locus model for the evolution of female choice for a male character associated with Meiotic Drive. Both Meiotic Drive and the male character are X-linked and the female preference is autosomal. Our model shows that suppressed recombination between Meiotic Drive and the male character, e.g. by inversion of the X chromosome, is necessary for sex-ratio selection to promote the origin of female mating preferences and exaggerated secondary sexual characters. With complete suppression of recombination, sexual selection reduces the frequency of Meiotic Drive, and may eliminate it. Very rare recombination, gene conversion or mutation, at rates characteristic of chromosome inversions in Drosophila, restores the Meiotic Drive polymorphism to its original equilibrium. Sex-ratio Meiotic Drive may thus act as a catalyst accelerating the origin of female mating preference and exaggerated male traits.

  • Sex Chromosome Meiotic Drive in Stalk-Eyed Flies
    Genetics, 1997
    Co-Authors: Daven C. Presgraves, Emily G. Severance, Gerald S. Wilkinson
    Abstract:

    Meiotically Driven sex chromosomes can quickly spread to fixation and cause population extinction unless balanced by selection or suppressed by genetic modifiers. We report results of genetic analyses that demonstrate that extreme female-biased sex ratios in two sister species of stalk-eyed flies, Cyrtodiopsis dalmanni and C. whitei, are due to a Meiotic Drive element on the X chromosome ( X d ). Relatively high frequencies of X d in C. dalmanni and C. whitei (13–17% and 29%, respectively) cause female-biased sex ratios in natural populations of both species. Sex ratio distortion is associated with spermatid degeneration in male carriers of X d . Variation in sex ratios is caused by Y -linked and autosomal factors that decrease the intensity of Meiotic Drive. Y -linked polymorphism for resistance to Drive exists in C. dalmanni in which a resistant Y chromosome reduces the intensity and reverses the direction of Meiotic Drive. When paired with X d , modifying Y chromosomes ( Y m ) cause the transmission of predominantly Y -bearing sperm, and on average, production of 63% male progeny. The absence of sex ratio distortion in closely related monomorphic outgroup species suggests that this Meiotic Drive system may predate the origin of C. whitei and C. dalmanni. We discuss factors likely to be involved in the persistence of these sex-linked polymorphisms and consider the impact of X d on the operational sex ratio and the intensity of sexual selection in these extremely sexually dimorphic flies.

Catherine Montchamp-moreau - One of the best experts on this subject based on the ideXlab platform.

  • The evolution of a sex-linked Meiotic Drive system in natural and experimental populations of Drosophila simulans
    2016
    Co-Authors: Pierre Gerard, David Ogereau, Quentin Helleu, Héloïse Bastide, Cécile Courret, Catherine Montchamp-moreau
    Abstract:

    The evolution of a sex-linked Meiotic Drive system in natural and experimental populations of [i]Drosophila simulans[/i] . Réunion du GDR Approche Interdisciplinaire de l’Evolution Moléculaire

  • Rapid evolution of a Y-chromosome heterochromatin protein underlies sex chromosome Meiotic Drive.
    Proceedings of the National Academy of Sciences of the United States of America, 2016
    Co-Authors: Quentin Helleu, David Ogereau, Pierre R. Gérard, Raphaëlle Dubruille, Benjamin Prud'homme, Benjamin Loppin, Catherine Montchamp-moreau
    Abstract:

    Sex chromosome Meiotic Drive, the non-Mendelian transmission of sex chromosomes, is the expression of an intragenomic conflict that can have extreme evolutionary consequences. However, the molecular bases of such conflicts remain poorly understood. Here, we show that a young and rapidly evolving X-linked heterochromatin protein 1 (HP1) gene, HP1D2, plays a key role in the classical Paris sex-ratio (SR) Meiotic Drive occurring in Drosophila simulans. Driver HP1D2 alleles prevent the segregation of the Y chromatids during meiosis II, causing female-biased sex ratio in progeny. HP1D2 accumulates on the heterochromatic Y chromosome in male germ cells, strongly suggesting that it controls the segregation of sister chromatids through heterochromatin modification. We show that Paris SR Drive is a consequence of dysfunctional HP1D2 alleles that fail to prepare the Y chromosome for meiosis, thus providing evidence that the rapid evolution of genes controlling the heterochromatin structure can be a significant source of intragenomic conflicts.

  • Selective Sweeps in a 2-Locus Model for Sex-Ratio Meiotic Drive in Drosophila simulans
    Molecular biology and evolution, 2007
    Co-Authors: Nicolas Derome, Emmanuelle Baudry, David Ogereau, Michel Veuille, Catherine Montchamp-moreau
    Abstract:

    A way to identify loci subject to positive selection is to detect the signature of selective sweeps in given chromosomal regions. It is revealed by the departure of DNA polymorphism patterns from the neutral equilibrium predicted by coalescent theory. We surveyed DNA sequence variation in a region formerly identified as causing "sex-ratio" Meiotic Drive in Drosophila simulans. We found evidence that this system evolved by positive selection at 2 neighboring loci, which thus appear to be required simultaneously for Meiotic Drive to occur. The 2 regions are approximately 150-kb distant, corresponding to a genetic distance of 0.1 cM. The presumably large transmission advantage of chromosomes carrying Meiotic Drive alleles at both loci has not erased the individual signature of selection at each locus. This chromosome fragment combines a high level of linkage disequilibrium between the 2 critical regions with a high recombination rate. As a result, 2 characteristic traits of selective sweeps--the reduction of variation and the departure from selective neutrality in haplotype tests--show a bimodal pattern. Linkage disequilibrium level indicates that, in the natural population from Madagascar used in this study, the selective sweep may be as recent as 100 years.

Andrew G Clark - One of the best experts on this subject based on the ideXlab platform.

  • sex ratio Meiotic Drive and y linked resistance in drosophila affinis
    Genetics, 2015
    Co-Authors: Robert L Unckless, Amanda M Larracuente, Andrew G Clark
    Abstract:

    Genetic elements that cheat Mendelian segregation by biasing transmission in their favor gain a significant fitness benefit. Several examples of sex-ratio Meiotic Drive, where one sex chromosome biases its own transmission at the cost of the opposite sex chromosome, exist in animals and plants. While the distorting sex chromosome gains a significant advantage by biasing sex ratio, the autosomes, and especially the opposite sex chromosome, experience strong selection to resist this transmission bias. In most well-studied sex-ratio Meiotic Drive systems, autosomal and/or Y-linked resistance has been identified. We specifically surveyed for Y-linked resistance to sex-ratio Meiotic Drive in Drosophila affinis by scoring the sex ratio of offspring sired by males with a driving X and one of several Y chromosomes. Two distinct types of resistance were identified: a restoration to 50/50 sex ratios and a complete reversal of sex ratio to all sons. We confirmed that fathers siring all sons lacked a Y chromosome, consistent with previously published work. Considerable variation in Y-chromosome morphology exists in D. affinis, but we showed that morphology does not appear to be associated with resistance to sex-ratio Meiotic Drive. We then used two X chromosomes (driving and standard) and three Y chromosomes (susceptible, resistant, and lacking) to examine fertility effects of all possible combinations. We find that both the driving X and resistant and lacking Y have significant fertility defects manifested in microscopic examination of testes and a 48-hr sperm depletion assay. Maintenance of variation in this sex-ratio Meiotic Drive system, including both the X-linked distorter and the Y-resistant effects, appear to be mediated by a complex interaction between fertility fitness and transmission dynamics.

  • SEX-RATIO Meiotic Drive AND INTERSPECIFIC COMPETITION
    Journal of evolutionary biology, 2014
    Co-Authors: Robert L Unckless, Andrew G Clark
    Abstract:

    It has long been known that processes occurring within a species may impact the interactions between species. For example, as competitive ability is sensitive to parameters including reproductive rate, carrying capacity and competition efficiency, the outcome of interspecific competition may be influenced by any process that alters these attributes. Although several such scenarios have been discussed, the influence of selfish genetic elements within one species on competition between species has not received theoretical treatment. We show that, with strong competition, sex-ratio Meiotic Drive systems can result in a significant shift in community composition because the effective birth rate in the population may be increased by a female-biased sex ratio. Using empirical data, we attempt to estimate the magnitude of this effect in several Drosophila species. We infer that Meiotic Drive elements, selfish genetic elements within species, can provide a substantial competitive advantage to that species within a community.

Hanna Kokko - One of the best experts on this subject based on the ideXlab platform.

  • coevolutionary dynamics of polyandry and sex linked Meiotic Drive
    Evolution, 2015
    Co-Authors: Luke Holman, Tom A. R. Price, Nina Wedell, Hanna Kokko
    Abstract:

    : Segregation distorters located on sex chromosomes are predicted to sweep to fixation and cause extinction via a shortage of one sex, but in nature they are often found at low, stable frequencies. One potential resolution to this longstanding puzzle involves female multiple mating (polyandry). Because many Meiotic Drivers severely reduce the sperm competitive ability of their male carriers, females are predicted to evolve more frequent polyandry and thereby promote sperm competition when a Meiotic Driver invades. Consequently, the driving chromosome's relative fitness should decline, halting or reversing its spread. We used formal modeling to show that this initially appealing hypothesis cannot resolve the puzzle alone: other selective pressures (e.g., low fitness of Drive homozygotes) are required to establish a stable Meiotic Drive polymorphism. However, polyandry and Meiotic Drive can strongly affect one another's frequency, and polyandrous populations may be resistant to the invasion of rare Drive mutants.

  • Coevolutionary dynamics of polyandry and sex‐linked Meiotic Drive
    Evolution; international journal of organic evolution, 2015
    Co-Authors: Luke Holman, Tom A. R. Price, Nina Wedell, Hanna Kokko
    Abstract:

    Segregation distorters located on sex chromosomes are predicted to sweep to fixation and cause extinction via a shortage of one sex, but in nature they are often found at low, stable frequencies. One potential resolution to this longstanding puzzle involves female multiple mating (polyandry). Because many Meiotic Drivers severely reduce the sperm competitive ability of their male carriers, females are predicted to evolve more frequent polyandry and thereby promote sperm competition when a Meiotic Driver invades. Consequently, the driving chromosome's relative fitness should decline, halting or reversing its spread. We used formal modeling to show that this initially appealing hypothesis cannot resolve the puzzle alone: other selective pressures (e.g., low fitness of Drive homozygotes) are required to establish a stable Meiotic Drive polymorphism. However, polyandry and Meiotic Drive can strongly affect one another's frequency, and polyandrous populations may be resistant to the invasion of rare Drive mutants.