Sex allocation plasticity on a transcriptome scale: socially-sensitive gene expression in a simultaneous hermaphrodite
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ABSTRACT:
ORGANISM(S): Macrostomum lignano
PROVIDER: GSE123594 | GEO | 2019/03/01
REPOSITORIES: GEO
Similar Datasets
Project description:Sex allocation plasticity on a transcriptome scale: socially-sensitive gene expression in a simultaneous hermaphrodite
| PRJNA511444 | ENA
Project description:Linking the evolution of the phenotype to the underlying genotype is a key aim of evolutionary genetics and is crucial to our understanding of how natural selection shapes a trait. Here we consider the genetic basis of sex allocation behaviour in the parasitoid wasp Nasonia vitripennis using a transcriptomics approach. Females allocate offspring sex in line with Local Mate Competition (LMC) theory. Female-biased sex ratios are produced when one or few females lay eggs on a patch. As the number of females contributing offspring to a patch increases, less female-biased sex ratios are favoured. We contrasted the transcriptomic responses of females as they oviposit under conditions known to influence sex allocation: foundress number (a social cue) and the state of the host (parasitised or not). We found, that when females encounter other females on a patch, or assess host quality with their ovipositors, the resulting changes in sex allocation is not associated with significant changes in whole-body gene expression. We also found that the gene expression changes produced by females, as they facultatively allocate sex in response to a host cue and a social cue, are very closely correlated. We expanded the list of candidate genes associated with oviposition behaviour in Nasonia, some of which may be involved in fundamental processes underlying the ability to facultatively allocate sex, including sperm storage and utilisation. 2 x 3 factorial design. Females were placed into 1 of 2 "foundress number" groups: 1) alone or 2) in the presence of 9 other females (co-foundresses). Females were further subdivided into host treatment groups: i) given no host, ii) given a fresh host and iii) given a pre-parasitised host. This gives a total of 6 possible treatment combinations. For each of these 6 groups, 7 pools of 10 females were sequenced giving 42 libraries altogether.
2015-11-11 | E-GEOD-74241 | biostudies-arrayexpress
Project description:Linking the evolution of the phenotype to the underlying genotype is a key aim of evolutionary genetics and is crucial to our understanding of how natural selection shapes a trait. Here we consider the genetic basis of sex allocation behaviour in the parasitoid wasp Nasonia vitripennis using a transcriptomics approach. Females allocate offspring sex in line with Local Mate Competition (LMC) theory. Female-biased sex ratios are produced when one or few females lay eggs on a patch. As the number of females contributing offspring to a patch increases, less female-biased sex ratios are favoured. We contrasted the transcriptomic responses of females as they oviposit under conditions known to influence sex allocation: foundress number (a social cue) and the state of the host (parasitised or not). We found, that when females encounter other females on a patch, or assess host quality with their ovipositors, the resulting changes in sex allocation is not associated with significant changes in whole-body gene expression. We also found that the gene expression changes produced by females, as they facultatively allocate sex in response to a host cue and a social cue, are very closely correlated. We expanded the list of candidate genes associated with oviposition behaviour in Nasonia, some of which may be involved in fundamental processes underlying the ability to facultatively allocate sex, including sperm storage and utilisation.
2015-11-11 | GSE74241 | GEO
Project description:Sex allocation theory predicts that the optimal sexual resource allocation of simultaneous hermaphrodites is affected by mating group size (MGS). Although the original concept assumes that the MGS does not differ between male and female functions, the MGS in the male function (MGSm; i.e., the number of sperm recipients the focal individual can deliver its sperm to plus one) and that in the female function (MGSf; the number of sperm donors plus one) do not always coincide and may differently affect the optimal sex allocation. Moreover, reproductive costs can be split into "variable" (e.g., sperm and eggs) and "fixed" (e.g., genitalia) costs, but these have been seldom distinguished in empirical studies. We examined the effects of MGSm and MGSf on the fixed and variable reproductive investments in the sessilian barnacle Balanus rostratus. The results showed that MGSm had a positive effect on sex allocation, whereas MGSf had a nearly significant negative effect. Moreover, the "fixed" cost varied with body size and both aspects of MGS. We argue that the two aspects of MGS should be distinguished for organisms with unilateral mating.
| S-EPMC7069306 | biostudies-literature
Project description:Evolutionary transitions between hermaphroditic and dioecious reproductive states are found in many groups of animals. To understand such transitions, it is important to characterize diverse modes of sex determination utilized by metazoans. Currently, little is known about how simultaneous hermaphrodites specify and maintain male and female organs in a single individual. Here we show that a sex-specific gene, Smed-dmd-1 encoding a predicted doublesex/male-abnormal-3 (DM) domain transcription factor, is required for specification of male germ cells in a simultaneous hermaphrodite, the planarian Schmidtea mediterranea. dmd-1 has a male-specific role in the maintenance and regeneration of the testes and male accessory reproductive organs. In addition, a homologue of dmd-1 exhibits male-specific expression in Schistosoma mansoni, a derived, dioecious flatworm. These results demonstrate conservation of the role of DM domain genes in sexual development in lophotrochozoans and suggest one means by which modulation of sex-specific pathways can drive the transition from hermaphroditism to dioecy.
| S-EPMC3674237 | biostudies-literature
Project description:Spotty wrasses (Notolabrus celidotus) undergo socially cued female-to-male sex change as adults. We combine captive social manipulations and time-series sampling with transcriptomic and methylome approaches to describe the molecular cascade that orchestrates gonadal metamorphosis. Our findings reveal at a molecular level how a normally committed developmental process remains plastic and is reversed to completely alter organ structures.
2020-05-17 | GSE150095 | GEO
Project description:Contrasting with separate-sexed animals, simultaneous hermaphrodites display unique reproductive strategies as they are male and female at the same time. Simultaneous hermaphrodites that copulate unilaterally, for instance, make a decision to mate as a male or female. Previous studies have demonstrated that sex role preference in hermaphrodites is flexible and is controlled by several, often confounding, factors. We examined the relationship between sex role decisions and 3 life-history traits (age, size, and mating history) in the great pond snail, Lymnaea stagnalis. Based on our field observations, which indicate that adult individuals show overlapping generations and large variation in body size during the breeding season, we performed a sex role choice experiment in the laboratory. We found that young and small snails mate as males first. Both age and size significantly affected sex role decision, with age having a stronger effect. Furthermore, we tested whether L. stagnalis becomes reluctant to inseminate a mate after being inseminated because it is known that after insemination, male investment substantially reduces. Contrary to expectations, our results indicate that the receipt of seminal fluid does not seem to reduce male motivation. In sum, sex role decisions in L. stagnalis are largely determined by age and size but not by having received seminal fluid. This mating pattern, however, does not fully support the size-advantage model because large or old individuals did not perform better as females in our experiment. These results imply a conflicting mating interest, rather than harmonious agreement, between age- and size-different hermaphrodites.
| S-EPMC4309981 | biostudies-literature
Project description:Asexual populations are usually considered evolutionary dead-ends because they lack the mechanisms to generate and maintain sufficient genetic diversity. Yet, some asexual forms are remarkably widespread and genetically diverse. This raises the question whether asexual systems are always truly clonal or whether they have cryptic forms of sexuality that enhance their viability. In the planarian flatworm Schmidtea polychroa parthenogens are functional hermaphrodites (as are their sexual conspecifics), copulate and exchange sperm. Sperm is required for initiation of embryogenesis but usually does not contribute genetically to the offspring (sperm-dependent parthenogenesis). Using karyology and genotyping of parents and offspring, we show that in a purely parthenogenetic population an estimated 12% of all offspring are the result of partial genetic exchange. Several processes of chromosome addition and loss are involved. Some of these result in an alternation between a common triploid and a rare tetraploid state. We conclude that genetic recombination does not necessarily require segregation and fusion within the same generation, as is the case in most sexual species. These occasional sexual processes help to explain the geographical dominance of parthenogens in our study species.
| S-EPMC1691700 | biostudies-other
Project description:A female's behavioral and physiological response to her environment can have lasting effects on the development of her offspring. This type of non-genetic inheritance (or maternal effect) occurs across taxa but is particularly well-studied in birds due to the relative ease of measuring maternal hormones in externally developing eggs. For example, females breeding in areas of high social competition allocate more of the hormone testosterone (T) to their egg yolks. These high-T offspring exhibit numerous phenotypic changes, including faster juvenile growth and enhanced aggression well into adulthood, which are potentially beneficial traits in high-competition areas. Thus, females may be able to communicate the current social environment to their offspring and prepare them for adverse conditions. Yet, the proximate mechanisms underlying how maternal hormones affect offspring are largely ignored, impairing our understanding of an ecologically important source of phenotypic plasticity. Here, we explored the effects of the maternal social environment on yolk T allocation and genome-wide patterns of neural gene expression in male and female tree swallow (Tachycineta bicolor) embryos. We observed a population of free-living tree swallows breeding at sites with variable breeding densities. We performed behavioral observations to record the rate of physical aggression at these sites, which was significantly higher at high density sites. We collected eggs at two developmental timepoints: the day laid to measure maternally derived T concentrations and embryonic day 11 (ED11) to measure gene expression patterns in whole brains using RNA-seq. We took a genome-wide approach to help clarify the potentially diverse mechanisms regulated by early T exposure across variable social environments. We additionally molecularly sexed the embryos to explore sex-specific effects.
2024-10-27 | GSE246544 | GEO
Project description:Local mate competition (LMC) occurs when male relatives compete for mating opportunities, and this may favour the evolution of female-biased sex allocation. LMC theory is among the most well developed and empirically supported topics in behavioural ecology, clarifies links between kin selection, group selection and game theory, and provides among the best quantitative evidence for Darwinian adaptation in the natural world. Two striking invariants arise from this body of work: the number of sons produced by each female is independent of both female fecundity and also the rate of female dispersal. Both of these invariants have stimulated a great deal of theoretical and empirical research. Here, we show that both of these invariants break down when variation in female fecundity and limited female dispersal are considered in conjunction. Specifically, limited dispersal of females following mating leads to local resource competition (LRC) between female relatives for breeding opportunities, and the daughters of high-fecundity mothers experience such LRC more strongly than do those of low-fecundity mothers. Accordingly, high-fecundity mothers are favoured to invest relatively more in sons, while low-fecundity mothers are favoured to invest relatively more in daughters, and the overall sex ratio of the population sex ratio becomes more female biased as a result.
| S-EPMC4590475 | biostudies-literature