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Misato Okamoto Miyakawa, Koji Tsuchida, Hitoshi Miyakawa
A female diploid, male haploid sex determination system (haplodiploidy) is found in hymenopteran taxa, such as ants, wasps, bees and sawflies. In this system, a single, complementary sex-determination (sl-CSD) locus functions as the primary sex-determination signal. In the taxa that has evolved this system, females and males are heterozygous and hemi/homozygous at the CSD locus, respectively. While the sl-CSD system enables females to alter sex ratios in the nest, it carries a high cost in terms of inbreeding, as individuals that are homozygous at the CSD locus become sterile diploid males...
February 2, 2018: Insect Biochemistry and Molecular Biology
Shinya Komata, Chung-Ping Lin, Teiji Sota
Female-limited Batesian mimicry may have evolved because of stronger predation pressure on females than on males, but some physiological costs of mimicry may also hinder the evolution of mimicry in males. In Papilio memnon, which possesses a female-limited Batesian mimicry polymorphism, two alleles at the doublesex (dsx) locus strictly control female phenotypes. To examine whether there are physiological costs associated with mimetic genotypes in the juvenile stage, we compered mortality, juvenile growth and development, and the resultant adult characteristics among three dsx genotypes (HH, Hh, hh) at a constant temperature (25°C) and two differing day lengths (LD 14:10 and LD 12:12; the latter might induce pupal diapause) by crossing individuals heterozygous (Hh) for the dsx allele...
February 2, 2018: Journal of Insect Physiology
Lydia Grmai, Bruno Hudry, Irene Miguel-Aliaga, Erika A Bach
Reproduction in sexually dimorphic animals relies on successful gamete production, executed by the germline and aided by somatic support cells. Somatic sex identity in Drosophila is instructed by sex-specific isoforms of the DMRT1 ortholog Doublesex (Dsx). Female-specific expression of Sex-lethal (Sxl) causes alternative splicing of transformer (tra) to the female isoform traF. In turn, TraF alternatively splices dsx to the female isoform dsxF. Loss of the transcriptional repressor Chinmo in male somatic stem cells (CySCs) of the testis causes them to "feminize", resembling female somatic stem cells in the ovary...
February 1, 2018: PLoS Genetics
Gavin Rice, Olga Barmina, Kevin Hu, Artyom Kopp
Male ornaments and other sex-specific traits present some of the most dramatic examples of evolutionary innovations. Comparative studies of similar but independently evolved traits are particularly important for identifying repeated patterns in the evolution of these traits. Male-specific modifications of the front legs have evolved repeatedly in Drosophilidae and other Diptera. The best understood of these novel structures is the sex comb of Drosophila melanogaster and its close relatives. Here, we examine the evolution of another male foreleg modification, the sex brush, found in the distantly related Drosophila immigrans species group...
January 25, 2018: Evolution & Development
Shihao Li, Fuhua Li, Kuijie Yu, Jianhai Xiang
The doublesex and its homologue genes are important regulators of sexual differentiation which are conserved among animal kingdom. In the present study, we reported a doublesex gene (designated as FcDsx) identified from the Chinese shrimp F. chinensis. The gene structure, nucleotide and deduced amino acid sequences of FcDsx were characterized. The results showed that the deduced amino acid sequence of FcDsx had the common features of Dsx proteins, including a doublesex/male abnormal 3 (DM) domain, an oligomerization domain and a predicted monopartite nuclear localization signal...
January 12, 2018: Gene
Sarah Rose C Garner, Monica C Castellanos, Katherine E Baillie, Tianshun Lian, Douglas W Allan
Female-specific Ilp7 neuropeptide-expressing motoneurons (FS-Ilp7 motoneurons) are required in Drosophila for oviduct function in egg laying. Here, we uncover cellular and genetic mechanisms underlying their female-specific generation. We demonstrate that programmed cell death (PCD) eliminates FS-Ilp7 motoneurons in males, and that this requires male-specific splicing of the sex-determination gene fruitless ( fru ) into the FruMC isoform. However, in females, fru alleles that only generate FruM isoforms failed to kill FS-Ilp7 motoneurons...
January 8, 2018: Development
Cezary Mikoluk, Alexis A Nagengast, Justin R DiAngelo
Excess nutrients are stored as triglycerides mainly in the adipose tissue of an animal and these triglycerides are located in structures called lipid droplets. Previous genome-wide RNAi screens in Drosophila cells identified splicing factors as playing a role in lipid droplet formation. Our lab has recently identified the SR protein, 9G8, as an important factor in fat storage as decreasing its levels results in augmented triglyceride storage in the fat body. Previous in vitro studies have implicated 9G8 in the regulation of splicing of the sex determination gene doublesex (dsx) by binding to transformer (tra) and transformer2 (tra2); however, any function of these sex determination proteins in regulating metabolism is unknown...
January 1, 2018: Biochemical and Biophysical Research Communications
S Bhardwaj, K L Prudic, A Bear, M D Gupta, B R Wasik, X Tong, W F Cheong, M R Wenk, A Monteiro
In contrast to the important role of hormones in the development of sexual traits in vertebrates (Cox, et al. 2009), the differentiation of these traits in insects is attributed almost exclusively to cell-autonomous mechanisms controlled by members of the sex determination pathway (Verhulst and van de Zande 2015), such as doublesex (dsx). Although hormones can shape the development of sexual traits in insects, variation in hormone levels are not conclusively known to cause dimorphism in these traits (Prakash and Monteiro 2016)...
November 20, 2017: Molecular Biology and Evolution
Xiaolong Yang, Mhd Ikhwanuddin, Xincang Li, Fan Lin, Qingyang Wu, Yueling Zhang, Cuihong You, Wenhua Liu, Yinwei Cheng, Xi Shi, Shuqi Wang, Hongyu Ma
The molecular mechanism underlying sex determination and gonadal differentiation of the mud crab (Scylla paramamosain) has received considerable attention, due to the remarkably biological and economic differences between sexes. However, sex-biased genes, especially non-coding genes, which account for these differences, remain elusive in this crustacean species. In this study, the first de novo gonad transcriptome sequencing was performed to identify both differentially expressed genes and long non-coding RNAs (lncRNAs) between male and female S...
November 20, 2017: Marine Biotechnology
Liying Zheng, Robert Carey, Eric Thorhauer, Scott Tashman, Christopher Harner, Xudong Zhang
We investigated the effects of isolated meniscectomy on tibiofemoral skeletal kinematics and cartilage contact arthrokinematics in vivo. We recruited nine patients who had undergone isolated medial or lateral meniscectomy, and used a dynamic stereo-radiography (DSX) system to image the patients' knee motion during decline walking. A volumetric model-based tracking process determined 3D tibiofemoral kinematics from the recorded DSX images. Cartilage contact arthrokinematics was derived from the intersection between tibial and femoral cartilage models co-registered to the bones...
November 6, 2017: Medical Engineering & Physics
Wei Zhang, Erica Westerman, Eyal Nitzany, Stephanie Palmer, Marcus R Kronforst
Supergene mimicry is a striking phenomenon but we know little about the evolution of this trait in any species. Here, by studying genomes of butterflies from a recent radiation in which supergene mimicry has been isolated to the gene doublesex, we show that sexually dimorphic mimicry and female-limited polymorphism are evolutionarily related as a result of ancient balancing selection combined with independent origins of similar morphs in different lineages and secondary loss of polymorphism in other lineages...
November 7, 2017: Nature Communications
Ryan M Byrne, Yu Zhou, Liying Zheng, Suman K Chowdhury, Ameet Aiyangar, Xudong Zhang
The lumbar facet joint (FJ) is often associated with pathogenesis in the spine, but quantification of normal FJ motion remains limited to in vitro studies or static imaging of non-functional poses. The purpose of this study was to quantify lumbar FJ kinematics in healthy individuals during functional activity with dynamic stereo radiography (DSX) imaging. Ten asymptomatic participants lifted three known weights starting from a trunk-flexed (∼75°) position to an upright position while being imaged within the DSX system...
October 19, 2017: Journal of Biomechanics
Nur Syafiqah Mohamad Ishak, Quang Dang Nong, Tomoaki Matsuura, Yasuhiko Kato, Hajime Watanabe
Divergence of upstream regulatory pathways of the transcription factor Doublesex (Dsx) serves as a basis for evolution of sex-determining mechanisms in animals. However, little is known about the regulation of Dsx in environmental sex determination. In the crustacean Daphnia magna, environmental sex determination is implemented by male-specific expression of the Dsx ortholog, Dsx1. Transcriptional regulation of Dsx1 comprises at least three phases during embryogenesis: non-sex-specific initiation, male-specific up-regulation, and its maintenance...
November 2017: PLoS Genetics
E Geuverink, E C Verhulst, M van Leussen, L van de Zande, L W Beukeboom
In many insect species maternal provision of sex-specifically spliced messenger RNA (mRNA) of sex determination genes is an essential component of the sex determination mechanism. In haplodiploid Hymenoptera, maternal provision in combination with genomic imprinting has been shown for the parasitoid Nasonia vitripennis, known as maternal effect genomic imprinting sex determination (MEGISD). Here, we characterize the sex determination cascade of Asobara tabida, another hymenopteran parasitoid. We show the presence of the conserved sex determination genes doublesex (dsx), transformer (tra) and transformer-2 (tra2) orthologues in As...
October 14, 2017: Insect Molecular Biology
Shinya Komata, Chung-Ping Lin, Teiji Sota
Tracking allele frequencies is essential for understanding how polymorphisms of adaptive traits are maintained. In Papilio memnon butterflies, which exhibit a female-limited Batesian mimicry polymorphism (wing-pattern polymorphism), two alleles at the doublesex (dsx) locus correspond to mimetic and non-mimetic forms in females; males carry both dsx alleles but display only the non-mimetic form. This polymorphism is thought to be maintained by a negative frequency-dependent selection. By tracking dsx allele frequencies in both sexes at a Taiwanese site over four years, we found that the mimetic allele persists at intermediate frequencies even when the unpalatable model papilionid butterflies (Pachliopta and Atrophaneura species) were very rare or absent...
October 10, 2017: Scientific Reports
Oliver M Beckers, Teiya Kijimoto, Armin P Moczek
Despite sharing nearly the same genome, individuals within the same species can vary drastically in both morphology and behaviour as a function of developmental stage, sex or developmental plasticity. Thus, regulatory processes must exist that enable the stage-, sex- or environment-specific expression of traits and their integration during ontogeny, yet exactly how trait complexes are co-regulated and integrated is poorly understood. In this study, we explore the developmental genetic basis of the regulation and integration of environment-dependent sexual dimorphism in behaviour and morphology in the horn-polyphenic dung beetle Onthophagus taurus through the experimental manipulation of the transcription factor doublesex (dsx)...
October 2017: Animal Behaviour
Elzemiek Geuverink, Anna H Rensink, Inge Rondeel, Leo W Beukeboom, Louis van de Zande, Eveline C Verhulst
In insect sex determination a primary signal starts the genetic sex determination cascade that, in most insect orders, is subsequently transduced down the cascade by a transformer (tra) ortholog. Only a female-specifically spliced tra mRNA yields a functional TRA-protein that forms a complex with TRA2, encoded by a transformer-2 (tra2) ortholog, to act as a sex specific splicing regulator of the downstream transcription factors doublesex (dsx) and fruitless (fru). Here, we identify the tra2 ortholog of the haplodiploid parasitoid wasp N...
November 2017: Insect Biochemistry and Molecular Biology
Shotaro Mine, Megumi Sumitani, Fugaku Aoki, Masatsugu Hatakeyama, Masataka G Suzuki
Sexual fate of the sawfly, Athalia rosae (Hymenoptera: Tenthredinidae) is determined by the complementary sex determination (CSD) mechanism as is the case in honeybees. However, to date, genes involved in sex determination have not been identified in this species. In this study, we attempted to identify orthologs of complementary sex-determiner (csd), feminizer (fem), and doublesex (dsx) from the A. rosae genome, all of which are crucial components of the sex determination cascade in the honeybee. As a result, we identified a sawfly ortholog of dsx (designated as Ardsx)...
2017: Applied Entomology and Zoology
Dandan Chen, Divya Sitaraman, Nan Chen, Xin Jin, Caihong Han, Jie Chen, Mengshi Sun, Bruce S Baker, Michael N Nitabach, Yufeng Pan
Animals execute one particular behavior among many others in a context-dependent manner, yet the mechanisms underlying such behavioral choice remain poorly understood. Here we studied how two fundamental behaviors, sex and sleep, interact at genetic and neuronal levels in Drosophila. We show that an increased need for sleep inhibits male sexual behavior by decreasing the activity of the male-specific P1 neurons that coexpress the sex determination genes fruM and dsx, but does not affect female sexual behavior...
July 28, 2017: Nature Communications
Muhammad Waqar Ali, Wenping Zheng, Summar Sohail, Qingmei Li, Weiwei Zheng, Hongyu Zhang
RNAi based sterile insect technique (SIT) is an authentic insect management approach but requires proper target genes. During this study, spermless males were developed by interfering with germ cell differentiation and azoospermia related genes. Data demonstrates significant reductions in the target genes expressions (boul, zpg, dsx (M) , fzo and gas8) after oral dsRNAs administration. Knock down of target genes significantly affected the reproductive ability of males and reduced egg-hatching as compared to the control group...
June 22, 2017: Scientific Reports
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