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David M. Shuker - One of the best experts on this subject based on the ideXlab platform.
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genomics of Sex Allocation in the parasitoid wasp nasonia vitripennis
BMC Genomics, 2020Co-Authors: Nicola Cook, Joost Van Den Heuvel, David M. ShukerAbstract:Whilst adaptive facultative Sex Allocation has been widely studied at the phenotypic level across a broad range of organisms, we still know remarkably little about its genetic architecture. Here, we explore the genome-wide basis of Sex ratio variation in the parasitoid wasp Nasonia vitripennis, perhaps the best studied organism in terms of Sex Allocation, and well known for its response to local mate competition. We performed a genome-wide association study (GWAS) for single foundress Sex ratios using iso-female lines derived from the recently developed outbred N. vitripennis laboratory strain HVRx. The iso-female lines capture a sample of the genetic variation in HVRx and we present them as the first iteration of the Nasonia vitripennis Genome Reference Panel (NVGRP 1.0). This panel provides an assessment of the standing genetic variation for Sex ratio in the study population. Using the NVGRP, we discovered a cluster of 18 linked SNPs, encompassing 9 annotated loci associated with Sex ratio variation. Furthermore, we found evidence that Sex ratio has a shared genetic basis with clutch size on three different chromosomes. Our approach provides a thorough description of the quantitative genetic basis of Sex ratio variation in Nasonia at the genome level and reveals a number of inter-related candidate loci underlying Sex Allocation regulation.
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genomics of Sex Allocation in the parasitoid wasp nasonia vitripennis
bioRxiv, 2020Co-Authors: Nicola Cook, Joost Van Den Heuvel, David M. ShukerAbstract:Background: Whilst adaptive facultative Sex Allocation has been widely studied at the phenotypic level across a broad range of organisms, we still know remarkably little about its genetic architecture. Here, we explore the genome-wide basis of Sex ratio variation in the parasitoid wasp Nasonia vitripennis, perhaps the best studied organism in terms of Sex Allocation, and well known for its response to local mate competition (LMC). Results: We performed a genome-wide association study (GWAS) for single foundress Sex ratios using iso-female lines derived from the recently developed outbred N. vitripennis laboratory strain HVRx. The iso-female lines capture a sample of the genetic variation in HVRx and we present them as the first iteration of the Nasonia vitripennis Genome Reference Panel (NVGRP 1.0). This panel provides an assessment of the standing genetic variation for Sex ratio in the study population. Using the NVGRP, we discovered a cluster of 18 linked SNPs, encompassing 9 annotated loci associated with Sex ratio variation. Furthermore, we found evidence that Sex ratio has a shared genetic basis with clutch size on three different chromosomes. Conclusions: Our approach provides a thorough description of the quantitative genetic basis of Sex ratio variation in Nasonia at the genome level and reveals a number of inter-related candidate loci underlying Sex Allocation regulation.
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differential gene expression is not required for facultative Sex Allocation a transcriptome analysis of brain tissue in the parasitoid wasp nasonia vitripennis
Royal Society Open Science, 2018Co-Authors: Nicola Cook, Rebecca A. Boulton, Urmi Trivedi, Bart A Pannebakker, Michael G Ritchie, Eran Tauber, Jade Green, David M. ShukerAbstract:Whole-transcriptome technologies have been widely used in behavioural genetics to identify genes associated with the performance of a behaviour and provide clues to its mechanistic basis. Here, we consider the genetic basis of Sex Allocation behaviour in the parasitoid wasp Nasonia vitripennis. Female Nasonia facultatively vary their offspring Sex ratio in line with Hamilton's theory of local mate competition (LMC). A single female or 'foundress' laying eggs on a patch will lay just enough sons to fertilize her daughters. As the number of 'foundresses' laying eggs on a patch increases (and LMC declines), females produce increasingly male-biased Sex ratios. Phenotypic studies have revealed the cues females use to estimate the level of LMC their sons will experience, but our understanding of the genetics underlying Sex Allocation is limited. Here, we exposed females to three foundress number conditions, i.e. three LMC conditions, and allowed them to oviposit. mRNA was extracted from only the heads of these females to target the brain tissue. The subsequent RNA-seq experiment confirmed that differential gene expression is not associated with the response to Sex Allocation cues and that we must instead turn to the underlying neuroscience to reveal the underpinnings of this impressive behavioural plasticity.
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oviposition but not Sex Allocation is associated with transcriptomic changes in females of the parasitoid wasp nasonia vitripennis
G3: Genes Genomes Genetics, 2015Co-Authors: Nicola Cook, Urmi Trivedi, Bart A Pannebakker, Mark Blaxter, Michael G Ritchie, Eran Tauber, Tanya Sneddon, David M. ShukerAbstract: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 behavior in the parasitoid wasp Nasonia vitripennis using a transcriptomics approach. Females allocate offspring Sex in line with the local mate competition (LMC) theory. Female-biased Sex ratios are produced when one or a few females lay eggs on a patch. As the number of females contributing offspring to a patch increases, less female-biased Sex ratios are favored. 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 (parasitized 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 behavior in Nasonia, some of which may be involved in fundamental processes underlying the ability to facultatively allocate Sex, including sperm storage and utilization.
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Beyond Sex Allocation: the role of mating systems in Sexual selection in parasitoid wasps
Biological reviews of the Cambridge Philosophical Society, 2014Co-Authors: Rebecca A. Boulton, Laura A. Collins, David M. ShukerAbstract:Despite the diverse array of mating systems and life histories which characterise the parasitic Hymenoptera, Sexual selection and Sexual conflict in this taxon have been somewhat overlooked. For instance, parasitoid mating systems have typically been studied in terms of how mating structure affects Sex Allocation. In the past decade, however, some studies have sought to address Sexual selection in the parasitoid wasps more explicitly and found that, despite the lack of obvious secondary Sexual traits, Sexual selection has the potential to shape a range of aspects of parasitoid reproductive behaviour and ecology. Moreover, various characteristics fundamental to the parasitoid way of life may provide innovative new ways to investigate different processes of Sexual selection. The overall aim of this review therefore is to re-examine parasitoid biology with Sexual selection in mind, for both parasitoid biologists and also researchers interested in Sexual selection and the evolution of mating systems more generally. We will consider aspects of particular relevance that have already been well studied including local mating structure, Sex Allocation and sperm depletion. We go on to review what we already know about Sexual selection in the parasitoid wasps and highlight areas which may prove fruitful for further investigation. In particular, sperm depletion and the costs of inbreeding under chromosomal Sex determination provide novel opportunities for testing the role of direct and indirect benefits for the evolution of mate choice.
Lukas Scharer - One of the best experts on this subject based on the ideXlab platform.
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Sex Allocation plasticity on a transcriptome scale socially sensitive gene expression in a simultaneous hermaphrodite
Molecular Ecology, 2019Co-Authors: Eugene Berezikov, Peter Ladurner, Steven A Ramm, Birgit Lengerer, Roberto Arbore, Robert Pjeta, Julia Wunderer, Athina Giannakara, Lukas ScharerAbstract:Phenotypic plasticity can enable organisms to produce optimal phenotypes in multiple environments. A crucial life history trait that is often highly plastic is Sex Allocation, which in simultaneous hermaphrodites describes the relative investment into the male versus female Sex functions. Theory predicts - and morphological evidence supports - that greater investment into the male function is favoured with increasing group size, due to the increasing importance of sperm competition for male reproductive success. Here we performed a genome-wide gene expression assay to test for such Sex Allocation plasticity in a model simultaneous hermaphrodite, the free-living flatworm Macrostomum lignano. Based on RNA-Seq data from 16 biological replicates spanning four different group size treatments, we demonstrate that at least 10% of the >75,000 investigated transcripts in M. lignano are differentially expressed according to the social environment, rising to >30% of putative gonad-specific transcripts (spermatogenesis and oogenesis candidates) and tail-specific transcripts (seminal fluid candidates). This transcriptional response closely corresponds to the expected shift away from female and towards male reproductive investment with increasing sperm competition level. Using whole-mount in situ hybridization, we then confirm that many plastic transcripts exhibit the expected organ-specific expression, and RNA interference of selected testis- and ovary-specific candidates establishes that these indeed function in gametogenesis pathways. We conclude that a large proportion of Sex-specific transcripts in M. lignano are differentially expressed according to the prevailing ecological conditions, and that these are functionally relevant to key reproductive phenotypes. Our study thus begins to bridge organismal and molecular perspectives on Sex Allocation plasticity. This article is protected by copyright. All rights reserved.
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No evidence for strong cytonuclear conflict over Sex Allocation in a simultaneously hermaphroditic flatworm
'Springer Science and Business Media LLC', 2017Co-Authors: Nikolas Vellnow, Dita B Vizoso, Gudrun Viktorin, Lukas ScharerAbstract:Abstract Background Cytoplasmic Sex Allocation distorters, which arise from cytonuclear conflict over the optimal investment into male versus female reproductive function, are some of the best-researched examples for genomic conflict. Among hermaphrodites, many such distorters have been found in plants, while, to our knowledge, none have been clearly documented in animals. Methods Here we provide a quantitative test for cytonuclear conflict over Sex Allocation in the simultaneously hermaphroditic flatworm Macrostomum lignano. We used a quantitative genetic breeding design, employing pair-wise crosses of 2 × 15 independent inbred lines, to partition the phenotypic variance in several traits (including Sex Allocation) into its nuclear and cytoplasmic components. Results Although the nuclear genetic background had a significant effect on all traits analyzed, we found significant cytoplasmic genetic variation only for ovary size, there explaining just 4.1% of the variance. A subsequent statistical power analysis showed that the experimental design had considerable power to detect cytonuclear interactions. Conclusion We conclude that there were no strong effects of cytonuclear conflict in the studied populations, possibly because the usually compact mitochondrial genomes in animals have a lower evolvability than the large mitochondrial genomes in plants or because the sampled populations currently do not harbor variation at putative distorter and/or the restorer loci
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Sex Allocation adjustment to mating group size in a simultaneous hermaphrodite
Evolution, 2013Co-Authors: Tim Janicke, Lucas Marieorleach, Katrien De Mulder, Eugene Berezikov, Peter Ladurner, Dita B Vizoso, Lukas ScharerAbstract:Sex Allocation theory is considered as a touchstone of evolutionary biology, providing some of the best supported examples for Darwinian adaptation. In particular, Hamilton's local mate competition theory has been shown to generate precise predictions for extraordinary Sex ratios observed in many separate-Sexed organisms. In analogy to local mate competition, Charnov's mating group size model predicts how Sex Allocation in simultaneous hermaphrodites is affected by the mating group size (i.e., the number of mating partners plus one). Until now, studies have not directly explored the relationship between mating group size and Sex Allocation, which we here achieve in the simultaneously hermaphroditic flatworm Macrostomum lignano. Using transgenic focal worms with ubiquitous expression of green-fluorescent protein (GFP), we assessed the number of wild-type mating partners carrying GFP+ sperm from these focal worms when raised in different social group sizes. This allowed us to test directly how mating group size was related to the Sex Allocation of focal worms. We find that the proportion of male investment initially increases with increasing mating group size, but then saturates as predicted by theory. To our knowledge, this is the first direct test of the mating group size model in a simultaneously hermaphroditic animal.
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Sex Allocation and investment into pre and post copulatory traits in simultaneous hermaphrodites the role of polyandry and local sperm competition
Philosophical Transactions of the Royal Society B, 2013Co-Authors: Lukas ScharerAbstract:Sex Allocation theory predicts the optimal Allocation to male and female reproduction in Sexual organisms. In animals, most work on Sex Allocation has focused on species with separate Sexes and our understanding of simultaneous hermaphrodites is patchier. Recent theory predicts that Sex Allocation in simultaneous hermaphrodites should strongly be affected by post-copulatory Sexual selection, while the role of pre-copulatory Sexual selection is much less clear. Here, we review Sex Allocation and Sexual selection theory for simultaneous hermaphrodites, and identify several strong and potentially unwarranted assumptions. We then present a model that treats Allocation to Sexually selected traits as components of Sex Allocation and explore patterns of Allocation when some of these assumptions are relaxed. For example, when investment into a male Sexually selected trait leads to skews in sperm competition, causing local sperm competition, this is expected to lead to a reduced Allocation to sperm production. We conclude that understanding the evolution of Sex Allocation in simultaneous hermaphrodites requires detailed knowledge of the different Sexual selection processes and their relative importance. However, little is currently known quantitatively about Sexual selection in simultaneous hermaphrodites, about what the underlying traits are, and about what drives and constrains their evolution. Future work should therefore aim at quantifying Sexual selection and identifying the underlying traits along the pre- to post-copulatory axis.
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Sex Allocation predicts mating rate in a simultaneous hermaphrodite
Proceedings of The Royal Society B: Biological Sciences, 2009Co-Authors: Tim Janicke, Lukas ScharerAbstract:Sexual selection theory for separate-Sexed animals predicts that the Sexes differ in the benefit they can obtain from multiple mating. Conventional Sex roles assume that the relationship between the number of mates and the fitness of an individual is steeper in males compared with females. Under these conditions, males are expected to be more eager to mate, whereas females are expected to be choosier. Here we hypothesize that the Sex Allocation, i.e. the reproductive investment devoted to the male versus female function, can be an important predictor of the mating strategy in simultaneous hermaphrodites. We argue that within-species variation in Sex Allocation can cause differences in the proportional fitness gain derived through each Sex function. Individuals should therefore adjust their mating strategy in a way that is more beneficial to the Sex function that is relatively more pronounced. To test this, we experimentally manipulated the Sex Allocation in a simultaneously hermaphroditic flatworm and investigated whether this affects the mating behaviour. The results demonstrate that individuals with a more male-biased Sex Allocation (i.e. relatively large testes and small ovaries) are more eager to mate compared with individuals with a more female-biased Sex Allocation (i.e. relatively small testes and large ovaries). We argue that this pattern is comparable to conventional gender roles in separate-Sexed organisms.
Laura Ross - One of the best experts on this subject based on the ideXlab platform.
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temporal variation in Sex Allocation in the mealybug planococcus citri adaptation constraint or both
Evolutionary Ecology, 2012Co-Authors: Laura Ross, Ido Pen, Minke B W Langenhof, David M. ShukerAbstract:Sex ratio theory has been very successful in predicting under which circumstances parents should bias their investment towards a particular offspring Sex. However, most examples of adaptive Sex ratio bias come from species with well-defined mating systems and Sex determining mechanisms, while in many other groups there is still an on-going debate about the adaptive nature of Sex Allocation. Here we study the Sex Allocation in the mealybug Planococcus citri, a species in which it is currently unclear how females adjust their Sex ratio, even though experiments have shown support for facultative Sex ratio adjustment. Previous work has shown that the Sex ratio females produce changes over the oviposition period, with males being overproduced early and late in the laying sequence. Here we investigate this complex pattern further, examining both the robustness of the pattern and possible explanations for it. We first show that this Sex Allocation behaviour is indeed consistent across lines from three geographical regions. Second, we test whether females produce sons first in order to synchronize reproductive maturation of her offspring, although our data provide little evidence for this adaptive explanation. Finally we test the age at which females are able to mate successfully and show that females are able to mate and store sperm before adult eclosion. Whilst early-male production may still function in promoting protandry in mealybugs, we discuss whether mechanistic constraints limit how female allocate Sex across their lifetime.
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temperature age of mating and starvation determine the role of maternal effects on Sex Allocation in the mealybug planococcus citri
Behavioral Ecology and Sociobiology, 2011Co-Authors: Leo W Beukeboom, Laura Ross, Elizabeth J Dealey, David M. ShukerAbstract:Environmental effects on Sex Allocation are common, yet the evolutionary significance of these effects remains poorly understood. Environmental effects might influence parents, such that their condition directly influences Sex Allocation by altering the relative benefits of producing sons versus daughters. Alternatively, the environment might influence the offspring themselves, such that the conditions they find themselves in influence their contribution to parental fitness. In both cases, parents might be selected to bias their Sex ratio according to the prevailing environmental conditions. Here, we consider Sex Allocation in the citrus mealybug Planococcus citri, a species with an unusual genetic system in which paternal genes are lost from the germline in males. We test environmental factors that may influence either female condition directly (rearing temperature and food restriction) or that may be used as cues of the future environment (age at mating). Using cytological techniques to obtain primary Sex ratios, we show that high temperature, older age at mating and starvation all affect Sex Allocation, resulting in female-biased Sex ratios. However, the effect of temperature is rather weak, and food restriction appears to be strongly associated with reduced longevity and a truncation of the usual schedule of male and offspring production across a female’s reproductive lifetime. Instead, facultative Sex Allocation seems most convincingly affected by age at mating, supporting previous work that suggests that social interactions experienced by adult P. citri females are used when allocating Sex. Our results highlight that, even within one species, different aspects of the environment may have conflicting effects on Sex Allocation.
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Sex Allocation in a species with paternal genome elimination the roles of crowding and female age in the mealybug planococcus citri
Evolutionary Ecology Research, 2010Co-Authors: Laura Ross, David M. Shuker, Stuart A. West, Ido Pen, Minke B W Langenhof, Leo W BeukeboomAbstract:Background: In species with paternal genome elimination, both Sexes are diploid. However, in males the chromosomes inherited from the father are deactivated during early development and eliminated from the germ line. Sex Allocation theory predicts that, all else being equal, females should bias their offspring Sex ratio towards the Sex that competes least with relatives. Organism: The mealybug Planococcus citri, a cosmopolitan pest on a wide range of agricultural and ornamental plant species. Hypothesis: In mealybugs, females compete locally for resources. To avoid competition among daughters, females should therefore produce a male-biased Sex ratio when alone, but a more equal Sex ratio when together with other unrelated females. This will result in a rise of the number of female offspring with density. However, competition associated with population density might have different fitness effects for male and female offspring respectively, because females need more resources and have less opportunity to migrate compared with males, selecting for the opposite pattern of Sex Allocation. Methods: Measuring Sex ratios in an experiment to manipulate the density a female experiences during two life stages. Results: Females that experienced high density as adults produced more male-biased Sex ratios. In addition, the Sex ratio females produced was strongly dependent on their age. Conclusion: Female mealybugs facultatively adjust their Sex ratio, but in the direction opposite to that predicted by local resource competition, suggesting that Sex-specific fitness consequences of density determine Sex Allocation in mealybugs.
Steven A Ramm - One of the best experts on this subject based on the ideXlab platform.
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Sex Allocation plasticity on a transcriptome scale socially sensitive gene expression in a simultaneous hermaphrodite
Molecular Ecology, 2019Co-Authors: Eugene Berezikov, Peter Ladurner, Steven A Ramm, Birgit Lengerer, Roberto Arbore, Robert Pjeta, Julia Wunderer, Athina Giannakara, Lukas ScharerAbstract:Phenotypic plasticity can enable organisms to produce optimal phenotypes in multiple environments. A crucial life history trait that is often highly plastic is Sex Allocation, which in simultaneous hermaphrodites describes the relative investment into the male versus female Sex functions. Theory predicts - and morphological evidence supports - that greater investment into the male function is favoured with increasing group size, due to the increasing importance of sperm competition for male reproductive success. Here we performed a genome-wide gene expression assay to test for such Sex Allocation plasticity in a model simultaneous hermaphrodite, the free-living flatworm Macrostomum lignano. Based on RNA-Seq data from 16 biological replicates spanning four different group size treatments, we demonstrate that at least 10% of the >75,000 investigated transcripts in M. lignano are differentially expressed according to the social environment, rising to >30% of putative gonad-specific transcripts (spermatogenesis and oogenesis candidates) and tail-specific transcripts (seminal fluid candidates). This transcriptional response closely corresponds to the expected shift away from female and towards male reproductive investment with increasing sperm competition level. Using whole-mount in situ hybridization, we then confirm that many plastic transcripts exhibit the expected organ-specific expression, and RNA interference of selected testis- and ovary-specific candidates establishes that these indeed function in gametogenesis pathways. We conclude that a large proportion of Sex-specific transcripts in M. lignano are differentially expressed according to the prevailing ecological conditions, and that these are functionally relevant to key reproductive phenotypes. Our study thus begins to bridge organismal and molecular perspectives on Sex Allocation plasticity. This article is protected by copyright. All rights reserved.
Nicola Cook - One of the best experts on this subject based on the ideXlab platform.
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genomics of Sex Allocation in the parasitoid wasp nasonia vitripennis
BMC Genomics, 2020Co-Authors: Nicola Cook, Joost Van Den Heuvel, David M. ShukerAbstract:Whilst adaptive facultative Sex Allocation has been widely studied at the phenotypic level across a broad range of organisms, we still know remarkably little about its genetic architecture. Here, we explore the genome-wide basis of Sex ratio variation in the parasitoid wasp Nasonia vitripennis, perhaps the best studied organism in terms of Sex Allocation, and well known for its response to local mate competition. We performed a genome-wide association study (GWAS) for single foundress Sex ratios using iso-female lines derived from the recently developed outbred N. vitripennis laboratory strain HVRx. The iso-female lines capture a sample of the genetic variation in HVRx and we present them as the first iteration of the Nasonia vitripennis Genome Reference Panel (NVGRP 1.0). This panel provides an assessment of the standing genetic variation for Sex ratio in the study population. Using the NVGRP, we discovered a cluster of 18 linked SNPs, encompassing 9 annotated loci associated with Sex ratio variation. Furthermore, we found evidence that Sex ratio has a shared genetic basis with clutch size on three different chromosomes. Our approach provides a thorough description of the quantitative genetic basis of Sex ratio variation in Nasonia at the genome level and reveals a number of inter-related candidate loci underlying Sex Allocation regulation.
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genomics of Sex Allocation in the parasitoid wasp nasonia vitripennis
bioRxiv, 2020Co-Authors: Nicola Cook, Joost Van Den Heuvel, David M. ShukerAbstract:Background: Whilst adaptive facultative Sex Allocation has been widely studied at the phenotypic level across a broad range of organisms, we still know remarkably little about its genetic architecture. Here, we explore the genome-wide basis of Sex ratio variation in the parasitoid wasp Nasonia vitripennis, perhaps the best studied organism in terms of Sex Allocation, and well known for its response to local mate competition (LMC). Results: We performed a genome-wide association study (GWAS) for single foundress Sex ratios using iso-female lines derived from the recently developed outbred N. vitripennis laboratory strain HVRx. The iso-female lines capture a sample of the genetic variation in HVRx and we present them as the first iteration of the Nasonia vitripennis Genome Reference Panel (NVGRP 1.0). This panel provides an assessment of the standing genetic variation for Sex ratio in the study population. Using the NVGRP, we discovered a cluster of 18 linked SNPs, encompassing 9 annotated loci associated with Sex ratio variation. Furthermore, we found evidence that Sex ratio has a shared genetic basis with clutch size on three different chromosomes. Conclusions: Our approach provides a thorough description of the quantitative genetic basis of Sex ratio variation in Nasonia at the genome level and reveals a number of inter-related candidate loci underlying Sex Allocation regulation.
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differential gene expression is not required for facultative Sex Allocation a transcriptome analysis of brain tissue in the parasitoid wasp nasonia vitripennis
Royal Society Open Science, 2018Co-Authors: Nicola Cook, Rebecca A. Boulton, Urmi Trivedi, Bart A Pannebakker, Michael G Ritchie, Eran Tauber, Jade Green, David M. ShukerAbstract:Whole-transcriptome technologies have been widely used in behavioural genetics to identify genes associated with the performance of a behaviour and provide clues to its mechanistic basis. Here, we consider the genetic basis of Sex Allocation behaviour in the parasitoid wasp Nasonia vitripennis. Female Nasonia facultatively vary their offspring Sex ratio in line with Hamilton's theory of local mate competition (LMC). A single female or 'foundress' laying eggs on a patch will lay just enough sons to fertilize her daughters. As the number of 'foundresses' laying eggs on a patch increases (and LMC declines), females produce increasingly male-biased Sex ratios. Phenotypic studies have revealed the cues females use to estimate the level of LMC their sons will experience, but our understanding of the genetics underlying Sex Allocation is limited. Here, we exposed females to three foundress number conditions, i.e. three LMC conditions, and allowed them to oviposit. mRNA was extracted from only the heads of these females to target the brain tissue. The subsequent RNA-seq experiment confirmed that differential gene expression is not associated with the response to Sex Allocation cues and that we must instead turn to the underlying neuroscience to reveal the underpinnings of this impressive behavioural plasticity.
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oviposition but not Sex Allocation is associated with transcriptomic changes in females of the parasitoid wasp nasonia vitripennis
G3: Genes Genomes Genetics, 2015Co-Authors: Nicola Cook, Urmi Trivedi, Bart A Pannebakker, Mark Blaxter, Michael G Ritchie, Eran Tauber, Tanya Sneddon, David M. ShukerAbstract: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 behavior in the parasitoid wasp Nasonia vitripennis using a transcriptomics approach. Females allocate offspring Sex in line with the local mate competition (LMC) theory. Female-biased Sex ratios are produced when one or a few females lay eggs on a patch. As the number of females contributing offspring to a patch increases, less female-biased Sex ratios are favored. 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 (parasitized 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 behavior in Nasonia, some of which may be involved in fundamental processes underlying the ability to facultatively allocate Sex, including sperm storage and utilization.
