Sex differentiation and the effect of post-larval cannibalism on the sex ratio in Brycon orbignyanus assessed by gonadal morphology and gene expression analysis

Sex differentiation and the effect of post-larval cannibalism on the sex ratio in Brycon orbignyanus assessed by gonadal morphology and gene expression analysis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Sex differentiation and the effect of post-larval cannibalism on the sex ratio in Brycon orbignyanus assessed by gonadal morphology and gene expression analysis Jhennifer Gomes Cordeiro, Amanda Pereira dos Santos Silva, Nivaldo Ferreira Nascimento, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7151879/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Brycon orbignyanus is an endangered fish species that is utilized in conservation strategies, including restocking programs. However, ex-situ practices, as artificial breeding, cause sexual ratio deviation, resulting in predominantly male offspring, which is not adequate for conservation programs. In this work, the main aspects of sexual differentiation were studied by monitoring gonadal differentiation and gene expression. Furthermore, the impact of larval cannibalism on the sexual ratio in both individual and collective post-larval cultures was examined, with sexual ratios assessed in the 12th month. S ox9 , dmrt1 , foxl2 , ddx20 , and ddx4 gene expressions were analyzed in oocytes, larvae, juveniles, and adults. Additionally, the juvenile gonads from the 6th to 12th month were examined through histological observations to identify the sexual differentiation. The gene expression results showed that the genes ddx4 and dmrt1 are specifically expressed in the gonads, while the other examined genes were also expressed in various tissues. The genes dmrt1 , foxl2 , and sox9 displayed dimorphic expression patterns in male and female gonads, and dmrt1 was not detected in larvae. In juveniles, the ovary was first identified in the 6th month, while the testis was observed from the 10th month through histological analysis. This analysis also revealed the presence of intersex individuals during gonadal development. No sex deviation (1:1) was observed in the grouped and individual rearing treatments. Sex differentiation was detected around the 6th month, indicating that artificial rearing at this stage is unlikely to affect the sex ratio. These findings are important for future research on understanding the sexual differentiation process in this species and for ex-situ practices. sexual ratio sexual differentiation intersex gonad restocking fish cannibalism Full Text Additional Declarations No competing interests reported. Supplementary Files FigureS1final.docx FigureS2final.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7151879","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":507171369,"identity":"fe491738-9a0c-4e0f-ae33-0d382d6be12c","order_by":0,"name":"Jhennifer Gomes Cordeiro","email":"","orcid":"","institution":"São Paulo State University","correspondingAuthor":false,"prefix":"","firstName":"Jhennifer","middleName":"Gomes","lastName":"Cordeiro","suffix":""},{"id":507171370,"identity":"083a7ba3-71ce-4ae5-8dc0-5e4a7af950d1","order_by":1,"name":"Amanda Pereira dos Santos Silva","email":"","orcid":"","institution":"Chico Mendes Institute of 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However, \u003cem\u003eex-situ\u003c/em\u003e practices, as artificial breeding, cause sexual ratio deviation, resulting in predominantly male offspring, which is not adequate for conservation programs. In this work, the main aspects of sexual differentiation were studied by monitoring gonadal differentiation and gene expression. Furthermore, the impact of larval cannibalism on the sexual ratio in both individual and collective post-larval cultures was examined, with sexual ratios assessed in the 12th month. S\u003cem\u003eox9\u003c/em\u003e, \u003cem\u003edmrt1\u003c/em\u003e, \u003cem\u003efoxl2\u003c/em\u003e, \u003cem\u003eddx20\u003c/em\u003e, and \u003cem\u003eddx4\u003c/em\u003e gene expressions were analyzed in oocytes, larvae, juveniles, and adults. Additionally, the juvenile gonads from the 6th to 12th month were examined through histological observations to identify the sexual differentiation. 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