scholarly journals Distinct developmental mechanisms influence sexual dimorphisms in the milkweed bug Oncopeltus fasciatus

2021 ◽  
Author(s):  
Josefine Just ◽  
Mara Laslo ◽  
Ye Jin Lee ◽  
Michael C Yarnell ◽  
Zhuofan Zhang ◽  
...  
Keyword(s):  
Sex Determination ◽  
The Body ◽  
Oncopeltus Fasciatus ◽  
Sexually Dimorphic ◽  
Specific Expression ◽  
X Chromosomes ◽  
Milkweed Bug ◽  
Multiple Transcripts ◽  
Complex Protein ◽  
Male Specific

Sexual dimorphism is a common feature of animals. Sex determination mechanisms vary widely among species and evolve rapidly. Until recently studies have found consistent mechanisms across the body of each individual determine female or male dimorphic body structures. In sexually dimorphic cells throughout the body of Drosophila, the relative dosage of autosomes and X chromosomes leads indirectly to alternatively spliced transcripts from the gene doublesex. The female Dsx isoform interacts with the mediator complex protein encoded by intersex to activate female development in flies. In males the transcription factor encoded by fruitless promotes male-specific behavior. In the milkweed bug Oncopeltus fasciatus, we find a requirement for different combinations of these genes during development of distinct dimorphic structures, within the same sex, suggesting a previously unappreciated level of diversity in sex determination. While intersex and fruitless are structurally conserved, doublesex has a history of duplication and divergence among Paraneoptera. Three doublesex paralogs in O. fasciatus produce multiple transcripts with sex- and tissue-specific expression. intersex and fruitless are expressed across the body, in females and males. RNA interference reveals only one doublesex paralog functions in somatic sex determination. Knockdown of doublesex and fruitless produces intersex phenotypic conditions in two sexually dimorphic structures: genitalia and abdominal sternites. In contrast, intersex is required for dimorphic development of female and male genitalia, but not for sternite dimorphism. These results reveal sex determination roles for intersex and fruitless distinct from their orthologs in other insects. Our results illuminate a novel form of developmental diversity in insect sex determination.

scholarly journals The Primary Sex Determination Signal of Caenorhabditis elegans

Genetics ◽  
1999 ◽  
Vol 152 (3) ◽  
pp. 999-1015 ◽  
Author(s):  
Ilil Carmi ◽  
Barbara J Meyer
Keyword(s):  
Caenorhabditis Elegans ◽  
Sex Determination ◽  
Counting Process ◽  
Rna Binding ◽  
Nuclear Hormone Receptor ◽  
Chromosome Counting ◽  
Specific Expression ◽  
X Chromosomes ◽  
Signal Element ◽  
Complete Transformation

AbstractAn X chromosome counting process determines sex in Caenorhabditis elegans. The dose of X chromosomes is translated into sexual fate by a set of X-linked genes that together control the activity of the sex-determination and dosage-compensation switch gene, xol-1. The double dose of X elements in XX animals represses xol-1 expression, promoting the hermaphrodite fate, while the single dose of X elements in XO animals permits high xol-1 expression, promoting the male fate. Previous work has revealed at least four signal elements that repress xol-1 expression at two levels, transcriptional and post-transcriptional. The two molecularly characterized elements include an RNA binding protein and a nuclear hormone receptor homolog. Here we explore the roles of the two mechanisms of xol-1 repression and further investigate how the combined dose of X signal elements ensures correct, sex-specific expression of xol-1. By studying the effects of increases and decreases in X signal element dose on male and hermaphrodite fate, we demonstrate that signal elements repress xol-1 cumulatively, such that full repression of xol-1 in XX animals results from the combined effect of individual elements. Complete transformation from the hermaphrodite to the male fate requires a decrease in the dose of all four elements, from two copies to one. We show that both mechanisms of xol-1 repression are essential and act synergistically to keep xol-1 levels low in XX animals. However, increasing repression by one mechanism can compensate for loss of the other, demonstrating that each mechanism can exert significant xol-1 repression on its own. Finally, we present evidence suggesting that xol-1 activity can be set at intermediate levels in response to an intermediate X signal.

scholarly journals Male specific expression suggests role of DMRT1 in human sex determination

2000 ◽  
Vol 91 (1-2) ◽  
pp. 323-325 ◽  
Author(s):  
Brigitte Moniot ◽  
Philippe Berta ◽  
Gerd Scherer ◽  
Peter Südbeck ◽  
Francis Poulat
Keyword(s):  
Sex Determination ◽  
Specific Expression ◽  
Male Specific

scholarly journals Dietary cardenolides enhance growth and change the direction of the fecundity-longevity trade-off in milkweed bugs (Heteroptera: Lygaeinae)

2021 ◽  
Author(s):  
Prayan Pokharel ◽  
Anke Steppuhn ◽  
Georg Petschenka
Keyword(s):  
Larval Growth ◽  
Life Time ◽  
The Body ◽  
Oncopeltus Fasciatus ◽  
Pyrrhocoris Apterus ◽  
Plant Toxins ◽  
Milkweed Bug ◽  
Body Tissues ◽  
Physiological Homeostasis ◽  
Growth And Change

1. Sequestration, i.e., the accumulation of plant toxins into body tissues for defence, is primarily observed in specialised insects. Sequestration was frequently predicted to incur a physiological cost mediated by increased exposure to plant toxins and may require resistance traits different from those of non-sequestering insects. Alternatively, sequestering species could experience a cost in the absence of toxins due to selection on physiological homeostasis under permanent exposure of sequestered toxins in body tissues. 2. Milkweed bugs (Heteroptera: Lygaeinae) sequester high amounts of plant-derived cardenolides. Although being potent inhibitors of the ubiquitous animal enzyme Na+/K+-ATPase, milkweed bugs can tolerate cardenolides by means of resistant Na+/K+-ATPases. Both adaptations, resistance and sequestration, are ancestral traits shared by most species of the Lygaeinae. 3. Using four milkweed bug species and the related European firebug (Pyrrhocoris apterus) showing different combinations of the traits ′cardenolide resistance′ and ′cardenolide sequestration′, we set out to test how the two traits affect larval growth upon exposure to dietary cardenolides in an artificial diet system. While cardenolides impaired the growth of P. apterus nymphs neither possessing a resistant Na+/K+-ATPase nor sequestering cardenolides, growth was not affected in the non-sequestering milkweed bug Arocatus longiceps, which possesses a resistant Na+/K+-ATPase. Remarkably, cardenolides increased growth in the sequestering dietary specialists Caenocoris nerii and Oncopeltus fasciatus but not in the sequestering dietary generalist Spilostethus pandurus, which all possess a resistant Na+/K+-ATPase. 4. We then assessed the effect of dietary cardenolides on additional life history parameters, including developmental speed, the longevity of adults, and reproductive success in O. fasciatus. Remarkably, nymphs under cardenolide exposure developed substantially faster and lived longer as adults. However, fecundity of adults was reduced when maintained on cardenolide-containing diet for their entire life-time but not when adults were transferred to non-toxic sunflower seeds. 5. We speculate that the resistant Na+/K+-ATPase of milkweed bugs is selected for working optimally in a ′toxic environment′, i.e. when sequestered cardenolides are stored in the body tissues. Contrary to the assumption that toxins sequestered for defence produce a physiological burden, our data suggest that they can even increase fitness in specialised insects.

scholarly journals A male-specific role for SOX9 in vertebrate sex determination

Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2813-2822 ◽  
Author(s):  
J. Kent ◽  
S.C. Wheatley ◽  
J.E. Andrews ◽  
A.H. Sinclair ◽  
P. Koopman
Keyword(s):  
Sex Determination ◽  
In Situ Hybridisation ◽  
Gonad Development ◽  
Adult Life ◽  
Cell Lineage ◽  
Polyclonal Antiserum ◽  
Cell Type Specificity ◽  
Sox9 Expression ◽  
Specific Expression ◽  
Male Specific

Mutation analyses of patients with campomelic dysplasia, a bone dysmorphology and XY sex reversal syndrome, indicate that the SRY-related gene SOX9 is involved in both skeletal development and sex determination. To clarify the role SOX9 plays in vertebrate sex determination, we have investigated its expression during gonad development in mouse and chicken embryos. In the mouse, high levels of Sox9 mRNA were found in male (XY) but not female (XX) genital ridges, and were localised to the sex cords of the developing testis. Purified fetal germ cells lacked Sox9 expression, indicating that Sox9 expression is specific to the Sertoli cell lineage. Sex specificity of SOX9 protein expression was confirmed using a polyclonal antiserum. The timing and cell-type specificity of Sox9 expression suggests that Sox9 may be directly regulated by SRY. Male-specific expression of cSOX9 mRNA during the sex determination period was also observed in chicken genital ridges. The conservation of sexually dimorphic expression in two vertebrate classes which have significant differences in their sex determination mechanisms, points to a fundamental role for SOX9 in testis determination in vertebrates. Sox9 expression was maintained in the mouse testis during fetal and adult life, but no expression was seen at any stage by in situ hybridisation in the developing ovary. Male-specific expression was also observed in the cells surrounding the Mullerian ducts and in the epididymis, and expression in both sexes was detected in the developing collecting ducts of the metanephric kidney. These results suggest that SOX9 may have a wider role in the development of the genitourinary system.

scholarly journals sisterless A is required for the activation of Sex lethal in the germline

2019 ◽  
Author(s):  
Raghav Goyal ◽  
Ellen Baxter ◽  
Mark Van Doren
Keyword(s):  
Sex Determination ◽  
X Chromosome ◽  
Germ Cells ◽  
Specific Expression ◽  
Male Germ Cells ◽  
X Chromosomes ◽  
Dna Elements ◽  
Sex Lethal ◽  
Female Specific ◽  
Necessary And Sufficient

ABSTRACTIn Drosophila, sex determination in somatic cells has been well-studied and is under the control of the switch gene Sex lethal (Sxl), which is activated in females by the presence of two X chromosomes. Though sex determination is regulated differently in the germline versus the soma, Sxl is also necessary and sufficient for the female identity in germ cells. Loss of Sxl function in the germline results in ovarian germline tumors, a characteristic of male germ cells developing in a female soma. Further, XY (male) germ cells expressing Sxl are able to produce eggs when transplanted into XX (female) somatic gonads, demonstrating that Sxl is also sufficient for female sexual identity in the germline. As in the soma, the presence of two X chromosomes is sufficient to activate Sxl in the germline, but the mechanism for “counting” X chromosomes in the germline is thought to be different from the soma. Here we have explored this mechanism at both cis- and trans-levels. Our data support the model that the Sxl “establishment” promoter (SxlPE) is activated in a female-specific manner in the germline, as in the soma, but that the timing of SxlPE activation, and the DNA elements that regulate SxlPE are different from those in the soma. Nevertheless, we find that the X chromosome-encoded gene sisterless A (sisA), which helps activate Sxl in the soma, is also essential for Sxl activation in the germline. Loss of sisA function leads to loss of Sxl expression in the germline, and to ovarian tumors and germline loss. These defects can be rescued by the expression of Sxl, demonstrating that sisA lies upstream of Sxl in germline sex determination. We conclude that sisA acts as an X chromosome counting element in both the soma and the germline, but that additional factors that ensure robust, female-specific expression of Sxl in the germline remain to be discovered.

On the evolution of sex determination

1987 ◽  
Vol 232 (1267) ◽  
pp. 159-180 ◽  
Keyword(s):  
Sex Determination ◽  
Sex Chromosome ◽  
Transplantation Antigen ◽  
Specific Cell ◽  
Serological Tests ◽  
Specific Expression ◽  
Heterogametic Sex ◽  
Taxonomic Groups ◽  
Male Specific ◽  
Specific Cell Surface

Female mice reject skin grafts from intrastrain males because of the H-Y transplantation antigen. Those females produce antibodies that recognize a male-specific cell-surface antigen in serological tests. The serological antigen has also been called ‘H-Y’, but there is evidence that the two antigens are distinct. We therefore refer to the transplantation antigen as H-Yt, or transplantation H-Y, and to the serological antigen as serological H-Y, or simply H-Y, without prejudice whether these are the same or related or separate antigens. In this study, sex-specific expression of serological H-Y antigen was found in 25 new vertebrate species representing each of seven major vertebrate classes.There was a strong correlation between expression of H-Y and occurrence of the heterogametic-type gonad, although unusual patterns of H-Y expression were noted in cases of temperature-influenced sex determination and in systems representing possible transition from one mode of heterogamety to the other. Male and female heterogamety are found side-by-side in certain freshwater toothed carps; and distinct sex chromosomes have been recognized in certain amphibians, even though they are not apparent in certain reptiles and primitíve birds. In seven ophidian species, in which the female is the heterogametic sex, H-Y was detected in the female; and in three species of Ranidae in which the male is heterogametic, it was detected in the male. In three species of cartilaginous fish and in one of the cyclostomes, in which heterogamety has not been ascertained, H-Y was detected in the male, suggesting that those primitive fishes are male-heterogametic. Evidently, then, heterogamety and sex-chromosome heteromorphism are polyphyletic, although certain sex-determining genes may be held in common among the diverse taxonomic groups.

scholarly journals The Snakeskin Gourami (Trichopodus pectoralis) Tends to Exhibit XX/XY Sex Determination

Fishes ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 43
Author(s):  
Thitipong Panthum ◽  
Nararat Laopichienpong ◽  
Ekaphan Kraichak ◽  
Worapong Singchat ◽  
Dung Ho My Nguyen ◽  
...  
Keyword(s):  
Sex Differences ◽  
Sex Determination ◽  
Y Chromosome ◽  
Cytogenetic Analysis ◽  
Genotyping By Sequencing ◽  
Sexually Dimorphic ◽  
Determination System ◽  
Sex Determination System ◽  
Male Specific ◽  
Determination Mechanism

The snakeskin gourami (Trichopodus pectoralis) has a high meat yield and is one of the top five aquaculture freshwater fishes in Thailand. The species is not externally sexually dimorphic, and its sex determination system is unknown. Understanding the sex determination system of this species will contribute to its full-scale commercialization. In this study, a cytogenetic analysis did not reveal any between-sex differences in chromosomal patterns. However, we used genotyping-by-sequencing to identify 4 male-linked loci and 1 female-linked locus, indicating that the snakeskin gourami tends to exhibit an XX/XY sex determination system. However, we did not find any male-specific loci after filtering the loci for a ratio of 100:0 ratio of males:females. This suggests that the putative Y chromosome is young and that the sex determination region is cryptic. This approach provides solid information that can help identify the sex determination mechanism and potential sex determination regions in the snakeskin gourami, allowing further investigation of genetic improvements in the species.

Genetics of sex determination: what can we learn from Drosophila?

Development ◽  
1987 ◽  
Vol 101 (Supplement) ◽  
pp. 17-24
Author(s):  
Rolf Nöthiger ◽  
Monica Steinmann-Zwicky
Keyword(s):  
Molecular Biology ◽  
Sex Determination ◽  
Genetic Control ◽  
Sexual Development ◽  
Sexual Differentiation ◽  
Regulatory Elements ◽  
Negative Control ◽  
Homeotic Genes ◽  
Specific Expression ◽  
X Chromosomes

The combined efforts of genetics, developmental and molecular biology have revealed the principles of genetic control of sexual differentiation in Drosophila. In combination with maternal components, a quantitative chromosomal signal, provided by the ratio of X chromosomes to sets of autosomes (X: A), regulates a key gene (Sxl). The functional state, ON or OFF, of Sxl, via a few subordinate regulatory genes, controls a switch gene (dsx) that can express two mutually exclusive functions, M or F. These serve to repress either the female or the male set of differentiation genes, thus directing the cells either into the male or into the female sexual pathway. Investigations of control genes and their regulation show that they have properties of homeotic genes. Their role is to select one of two alternative developmental programs. Their function, or lack of function, is required throughout development to maintain the cells in their respective sexual pathway. Differentiation genes are under negative control by dsx. We discuss the cis- and tams-regulatory elements that are needed for sex-, tissue- and stage-specific expression of the differentiation genes. A comparison of Drosophila to other organisms such as Caenorhabditis, mammals and other insects indicates similarities that we interpret as evidence for a basically invariant genetic strategy used by various organisms to regulate sexual development.

scholarly journals PDF-1 neuropeptide signaling regulates sexually dimorphic gene expression in shared sensory neurons of C. elegans

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Zoë A Hilbert ◽  
Dennis H Kim
Keyword(s):  
Sexually Dimorphic ◽  
Specific Expression ◽  
C Elegans ◽  
Pigment Dispersing Factor ◽  
Behavioral Decision ◽  
Specific Effects ◽  
Sexually Dimorphic Expression ◽  
Male Specific ◽  
Dimorphic Gene Expression ◽  
Dimorphic Expression

Sexually dimorphic behaviors are a feature common to species across the animal kingdom, however how such behaviors are generated from mostly sex-shared nervous systems is not well understood. Building on our previous work which described the sexually dimorphic expression of a neuroendocrine ligand, DAF-7, and its role in behavioral decision-making in C. elegans (Hilbert and Kim, 2017), we show here that sex-specific expression of daf-7 is regulated by another neuroendocrine ligand, Pigment Dispersing Factor (PDF-1), which has previously been implicated in regulating male-specific behavior (Barrios et al., 2012). Our analysis revealed that PDF-1 signaling acts sex- and cell-specifically in the ASJ neurons to regulate the expression of daf-7, and we show that differences in PDFR-1 receptor activity account for the sex-specific effects of this pathway. Our data suggest that modulation of the sex-shared nervous system by a cascade of neuroendocrine signals can shape sexually dimorphic behaviors.

scholarly journals A sexually dimorphic neuroendocrine cascade acts through shared sensory neurons to regulate behavior inC. elegans

2018 ◽  
Author(s):  
Zoë A. Hilbert ◽  
Dennis H. Kim
Keyword(s):  
Sexually Dimorphic ◽  
Animal Kingdom ◽  
Specific Expression ◽  
C Elegans ◽  
Pigment Dispersing Factor ◽  
Behavioral Decision ◽  
Specific Effects ◽  
Sexually Dimorphic Expression ◽  
Male Specific ◽  
Dimorphic Expression

ABSTRACTSexually dimorphic behaviors are observed in species across the animal kingdom, however the relative contributions of sex-specific and sex-shared nervous systems to such behaviors are not fully understood. Building on our previous work which described the sexually dimorphic expression of a neuroendocrine ligand, DAF-7, and its role in behavioral decision-making inC. elegans(Hilbert and Kim, 2017), we show here that sex-specific expression ofdaf-7is regulated by another neuroendocrine ligand, Pigment Dispersing Factor (PDF-1), which has previously been implicated in regulating male-specific behavior (Barrios et al., 2012). Our analysis revealed that PDF-1 acts sex- and cell-specifically in the ASJ neurons to regulate the expression ofdaf-7and we show that differences in the expression of the PDFR-1 receptor account for the sex-specific effects of this pathway. Our data suggest that modulation of the sex-shared nervous system by neuroendocrine signaling pathways can play a role in shaping sexually dimorphic behaviors.

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