scholarly journals Sexual Dimorphism in Growth Rate and Gene Expression Throughout Immature Development in Wild Type Chrysomya rufifacies (Diptera: Calliphoridae) Macquart

2021 ◽  
Vol 9 ◽  
Author(s):  
Meaghan L. Pimsler ◽  
Carl E. Hjelmen ◽  
Michelle M. Jonika ◽  
Anika Sharma ◽  
Shuhua Fu ◽  
...  

Reliability of forensic entomology analyses to produce relevant information to a given case requires an understanding of the underlying arthropod population(s) of interest and the factors contributing to variability. Common traits for analyses are affected by a variety of genetic and environmental factors. One trait of interest in forensic investigations has been species-specific temperature-dependent growth rates. Recent work indicates sexual dimorphism may be important in the analysis of such traits and related genetic markers of age. However, studying sexual dimorphic patterns of gene expression throughout immature development in wild-type insects can be difficult due to a lack of genetic tools, and the limits of most sex-determination mechanisms. Chrysomya rufifacies, however, is a particularly tractable system to address these issues as it has a monogenic sex determination system, meaning females have only a single-sex of offspring throughout their life. Using modified breeding procedures (to ensure single-female egg clutches) and transcriptomics, we investigated sexual dimorphism in development rate and gene expression. Females develop slower than males (9 h difference from egg to eclosion respectively) even at 30°C, with an average egg-to-eclosion time of 225 h for males and 234 h for females. Given that many key genes rely on sex-specific splicing for the development and maintenance of sexually dimorphic traits, we used a transcriptomic approach to identify different expression of gene splice variants. We find that 98.4% of assembled nodes exhibited sex-specific, stage-specific, to sex-by-stage specific patterns of expression. However, the greatest signal in the expression data is differentiation by developmental stage, indicating that sexual dimorphism in gene expression during development may not be investigatively important and that markers of age may be relatively independent of sex. Subtle differences in these gene expression patterns can be detected as early as 4 h post-oviposition, and 12 of these nodes demonstrate homology with key Drosophila sex determination genes, providing clues regarding the distinct sex determination mechanism of C. rufifacies. Finally, we validated the transcriptome analyses through qPCR and have identified five genes that are developmentally informative within and between sexes.

Science ◽  
2021 ◽  
Vol 371 (6527) ◽  
pp. 396-400 ◽  
Author(s):  
Charalampos Chrysovalantis Galouzis ◽  
Benjamin Prud’homme

Sexual dimorphism in animals results from sex-biased gene expression patterns. These patterns are controlled by genetic sex determination hierarchies that establish the sex of an individual. Here we show that the male-biased wing expression pattern of the Drosophila biarmipes gene yellow, located on the X chromosome, is independent of the fly sex determination hierarchy. Instead, we find that a regulatory interaction between yellow alleles on homologous chromosomes (a process known as transvection) silences the activity of a yellow enhancer functioning in the wing. Therefore, this enhancer can be active in males (XY) but not in females (XX). This transvection-dependent enhancer silencing requires the yellow intron and the chromatin architecture protein Mod(mdg4). Our results suggest that transvection can contribute more generally to the sex-biased expression of X-linked genes.


Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 873
Author(s):  
Shahrbanou Hosseini ◽  
Armin Otto Schmitt ◽  
Jens Tetens ◽  
Bertram Brenig ◽  
Henner Simianer ◽  
...  

The transcriptional regulation of gene expression in higher organisms is essential for different cellular and biological processes. These processes are controlled by transcription factors and their combinatorial interplay, which are crucial for complex genetic programs and transcriptional machinery. The regulation of sex-biased gene expression plays a major role in phenotypic sexual dimorphism in many species, causing dimorphic gene expression patterns between two different sexes. The role of transcription factor (TF) in gene regulatory mechanisms so far has not been studied for sex determination and sex-associated colour patterning in zebrafish with respect to phenotypic sexual dimorphism. To address this open biological issue, we applied bioinformatics approaches for identifying the predicted TF pairs based on their binding sites for sex and colour genes in zebrafish. In this study, we identified 25 (e.g., STAT6-GATA4; JUN-GATA4; SOX9-JUN) and 14 (e.g., IRF-STAT6; SOX9-JUN; STAT6-GATA4) potentially cooperating TFs based on their binding patterns in promoter regions for sex determination and colour pattern genes in zebrafish, respectively. The comparison between identified TFs for sex and colour genes revealed several predicted TF pairs (e.g., STAT6-GATA4; JUN-SOX9) are common for both phenotypes, which may play a pivotal role in phenotypic sexual dimorphism in zebrafish.


2018 ◽  
Author(s):  
Αλέξανδρος Τσακογιάννης

The differences between sexes and the concept of sex determination have always fascinated, yet troubled philosophers and scientists. Among the animals that reproduce sexually, teleost fishes show a very wide repertoire of reproductive modes. Except for the gonochoristic species, fish are the only vertebrates in which hermaphroditism appears naturally. Hermaphroditism refers to the capability of an organism to reproduce both as male and female in its life cycle and there are various forms of it. In sequential hermaphroditism, an individual begins as female first and then can change sex to become male (protogyny), or vice versa (protandry). The diverse sex-phenotypes of fish are regulated by a variety of sex determination mechanisms, along a continuum of environmental and heritable factors. The vast majority of sexually dimorphic traits result from the differential expression of genes that are present in both sexes. To date, studies regarding the sex-specific differences in gene expression have been conducted mainly in sex determination systems of model fish species that are well characterized at the genomic level, with distinguishable heteromorphic sex chromosomes, exhibiting genetic sex determination and gonochorism. Among teleosts, the Sparidae family is considered to be one of the most diversified families regarding its reproductive systems, and thus is a unique model for comparative studies to understand the molecular mechanisms underlying different sexual motifs. In this study, using RNA sequencing, we studied the transcriptome from gonads and brains of both sexes in five sparid species, representatives of four different reproductive styles. Specifically, we explored the sex-specific expression patterns of a gonochoristic species: the common dentex Dentex dentex, two protogynous hermaphrodites: the red porgy Pagrus pagrus and the common pandora Pagellus erythrinus, the rudimentary hermaphrodite sharpsnout seabream Diplodus puntazzo, and the protandrous gilthead seabream Sparus aurata. We found minor sex-related expression differences indicating a more homogeneous and sexually plastic brain, whereas there was a plethora of sex biased gene expression in the gonads. The functional divergence of the two gonadal types is reflected in their transcriptomic profiles, in terms of the number of genes differentially expressed, as well as the expression magnitude (i.e. fold-change differences). The observation of almost double the number of up-regulated genes in males compared to females indicates a male-biased expression tendency. Focusing on the pathways and genes implicated in sex determination/differentiation, we aimed to unveil the molecular pathways through which these non-model fish species develop a masculine or a feminine character. We observed the implicated pathways and major gene families (e.g. Wnt/b-catenin pathway and Retinoic-acid signaling pathway, Notch, TGFβ) behind sex-biased expression and the recruitment of known sex-related genes either to male or female type of gonads in these fish. (e.g Dmrt1, Sox9, Sox3, Cyp19a, Filgla, Ctnnb1, Gsdf9, Stra6 etc.). We also carefully investigated the presence of genes reported to be involved in sex determination/differentiation mechanisms in other vertebrates and fish and compared their expression patterns in the species under study. The expression profiling exposed known candidate molecular-players/genes establishing the common female (Cyp19a1, Sox3, Figla, Gdf9, Cyp26a, Ctnnb1, Dnmt1, Stra6) and male identity (Dmrt1, Sox9, Dnmt3aa, Rarb, Raraa, Hdac8, Tdrd7) of the gonad in these sparids. Additionally, we focused on those contributing to a species-specific manner either to female (Wnt4a, Dmrt2a, Foxl2 etc.) or to male (Amh, Dmrt3a, Cyp11b etc.) characters, and discussed the expression patterns of factors that belong to important pathways and/or gene families in the SD context, in our species gonadal transcriptomes. Taken together, most of the studied genes form part of the cascade of sex determination, differentiation, and reproduction across teleosts. In this study, we focused on genes that are active when sex is established (sex-maintainers), revealing the basic “gene-toolkit” & gene-networks underlying functional sex in these five sparids. Comparing related species with alternative reproductive styles, we saw different combinations of genes with conserved sex-linked roles and some “handy” molecular players, in a “partially- conserved” or “modulated” network formulating the male and female phenotype. The knowledge obtained in this study and tools developed during the process have set the groundwork for future experiments that can improve the sex control of this species and help the in-deep understanding the complex process of sex differentiation in the more flexible multi-component systems as these studied here.


2015 ◽  
Author(s):  
Chiara Colombo ◽  
Loris De Cecco ◽  
Antonino Belfiore ◽  
Silvana Canevari ◽  
Marco Fiore ◽  
...  

2013 ◽  
Vol 368 (1632) ◽  
pp. 20130022 ◽  
Author(s):  
Noboru Jo Sakabe ◽  
Marcelo A. Nobrega

The complex expression patterns observed for many genes are often regulated by distal transcription enhancers. Changes in the nucleotide sequences of enhancers may therefore lead to changes in gene expression, representing a central mechanism by which organisms evolve. With the development of the experimental technique of chromatin immunoprecipitation (ChIP), in which discrete regions of the genome bound by specific proteins can be identified, it is now possible to identify transcription factor binding events (putative cis -regulatory elements) in entire genomes. Comparing protein–DNA binding maps allows us, for the first time, to attempt to identify regulatory differences and infer global patterns of change in gene expression across species. Here, we review studies that used genome-wide ChIP to study the evolution of enhancers. The trend is one of high divergence of cis -regulatory elements between species, possibly compensated by extensive creation and loss of regulatory elements and rewiring of their target genes. We speculate on the meaning of the differences observed and discuss that although ChIP experiments identify the biochemical event of protein–DNA interaction, it cannot determine whether the event results in a biological function, and therefore more studies are required to establish the effect of divergence of binding events on species-specific gene expression.


2016 ◽  
Vol 85 (1) ◽  
Author(s):  
Wenchao Feng ◽  
Dylan Minor ◽  
Mengyao Liu ◽  
Jinquan Li ◽  
Suzanne L. Ishaq ◽  
...  

ABSTRACT Group A Streptococcus (GAS) acquires mutations of the virulence regulator CovRS in human and mouse infections, and these mutations result in the upregulation of virulence genes and the downregulation of the protease SpeB. To identify in vivo mutants with novel phenotypes, GAS isolates from infected mice were screened by enzymatic assays for SpeB and the platelet-activating factor acetylhydrolase Sse, and a new type of variant that had enhanced Sse expression and normal levels of SpeB production was identified (the variants had a phenotype referred to as enhanced Sse activity [SseA+] and normal SpeB activity [SpeBA+]). SseA+ SpeBA+ variants had transcript levels of CovRS-controlled virulence genes comparable to those of a covS mutant but had no covRS mutations. Genome resequencing of an SseA+ SpeBA+ isolate identified a C605A nonsense mutation in orphan kinase gene rocA, and 6 other SseA+ SpeBA+ isolates also had nonsense mutations or small indels in rocA. RocA and CovS mutants had similar levels of enhancement of the expression of CovRS-controlled virulence genes at the exponential growth phase; however, mutations of RocA but not mutations of CovS did not result in the downregulation of speB transcription at stationary growth phase or in subcutaneous infection of mice. GAS with RocA and CovS mutations caused greater enhancement of the expression of hasA than spyCEP in mouse skin infection than wild-type GAS did. RocA mutants ranked between wild-type GAS and CovS mutants in skin invasion, inhibition of neutrophil recruitment, and virulence in subcutaneous infection of mice. Thus, GAS RocA mutants can be selected in subcutaneous infections in mice and exhibit gene expression patterns and virulences distinct from those of CovS mutants. The findings provide novel information for understanding GAS fitness mutations in vivo, virulence gene regulation, in vivo gene expression, and virulence.


2021 ◽  
Author(s):  
Dieter Mueller ◽  
Enora Gachet ◽  
Olivier Godfroy ◽  
Josselin Gueno ◽  
Guillaume Cossard ◽  
...  

In UV sexual systems, sex is determined during the haploid phase of the life cycle and males have a V chromosome whereas females have a U chromosome. Previous work in the brown algal model Ectocarpus revealed that the V chromosome has a dominant role in male sex determination and suggested that the female developmental program may occur by default, triggered in the absence of the male master sex determination gene(s). Here, we describe the identification of a genetically male giant kelp strain presenting phenotypic features typical of a female, despite lacking the U-specific region. The conversion to the female developmental program is however incomplete, because gametes of this feminised male are unable to produce the sperm-attracting pheromone lamoxirene. We identify the transcriptomic patterns underlying the male and female specific developmental programs, and reveal the faster evolutionary rates of male-biased genes compared to female-biased and unbiased genes. Moreover, we show that the phenotypic feminisation of the variant strain is associated with both feminisation and de-masculinisation of gene expression patterns. Importantly, the feminisation phenotype was associated with the dramatic downregulation of two V-specific genes including a candidate sex-determining gene on the V-specific region. Our results reveal the transcriptional changes associated with sexual differentiation in a UV system with marked sexual dimorphism, and contribute to disentangling the role of sex-linked genes and autosomal gene expression in the initiation of the male and female developmental programs. Overall, the data presented here imply that the U-specific region in the giant kelp is not required to initiate the female developmental program, but is critical to produce fully functional eggs, arguing against the idea that female is the default sex in this species.


2021 ◽  
Author(s):  
Catriona Munro ◽  
Felipe Zapata ◽  
Mark Howison ◽  
Stefan Siebert ◽  
Casey W Dunn

Background: Siphonophores are complex colonial animals, consisting of asexually-produced bodies (called zooids) that are functionally specialized for specific tasks, including feeding, swimming, and sexual reproduction. Though this extreme functional specialization has captivated biologists for generations, its genomic underpinnings remain unknown. We use RNA-seq to investigate gene expression patterns in five zooids and one specialized tissue (pneumatophore) across seven siphonophore species. Analyses of gene expression across species present several challenges, including identification of comparable expression changes on gene trees with complex histories of speciation, duplication, and loss. Here, we conduct three analyses of expression. First, we examine gene expression within species. Then, we conduct classical analyses examining expression patterns between species. Lastly, we introduce Speciation Branch Filtering, which allows us to examine the evolution of expression in a phylogenetic framework. Results: Within and across species, we identified hundreds of zooid-specific and species-specific genes, as well as a number of putative transcription factors showing differential expression in particular zooids and developmental stages. We found that gene expression patterns tended to be largely consistent in zooids with the same function across species, but also some large lineage-specific shifts in gene expression. Conclusions: Our findings show that patterns of gene expression have the potential to define zooids in colonial organisms. We also show that traditional analyses of the evolution of gene expression focus on the tips of gene phylogenies, identifying large-scale expression patterns that are zooid or species variable. The new explicit phylogenetic approach we propose here focuses on branches (not tips) offering a deeper evolutionary perspective into specific changes in gene expression within zooids along all branches of the gene (and species) trees.


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