Zebrafish (Danio rerio) studies describe before the onset of mature gonads differentiation all individuals go through a "juvenile ovary" stage. However, the sequential events of the early zebrafish gonad differentiation are still not described in full detail and recent works indicate that some individuals never form a "juvenile ovary" structure. Therefore, the present study aimed to confirm the existence of two processes of zebrafish male differentiation. For this purpose, every two days between 20 and 30 days post-fertilization (dpf) zebrafish were collected for a stereological analysis of the differentiating gonads. The histological evaluation showed that prior to 22 dpf, zebrafish gonads were still undifferentiated. At 24 dpf, some individuals started to present a "juvenile ovary" and from 26 to 30 dpf, it was possible to discern two processes of gonad development. The majority of the individuals (80 %) developed a "juvenile ovary", while in the remaining (20 %) it was not possible to detect this structure. The results of the present study show the existence of two distinct processes of zebrafish male gonad development, indicating that not all individuals go through the "juvenile ovary" stage.
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http://dx.doi.org/10.1016/j.tice.2021.101545 | DOI Listing |
Gen Comp Endocrinol
November 2024
Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan; National Laboratory Animal Center, National Applied Research Laboratories, Taipei 115, Taiwan; Graduate Institute of Biomedical Sciences, Neuroscience and Brain Disease Center, China Medical University, Taichung 404, Taiwan. Electronic address:
Zebrafish sex chromosomes have been identified in the wild Nadia (NA) strain, and its sex determination belongs to the female-heterogametic ZZ/ZW system. Here, we investigate the correlation between ZZ/ZW sex chromosomes in the NA strain with sex-related factors, and sort out the complicated process of sex determination in zebrafish. Two phases exist during zebrafish sex differentiation.
View Article and Find Full Text PDFZool Res
September 2024
Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Hubei Hongshan Laboratory, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, Hubei 430072, China.
Zebrafish serve as a valuable model organism for studying germ cell biology and reproductive processes. The AB strain of zebrafish is proposed to exhibit a polygenic sex determination system, where most males initially develop juvenile ovaries before committing to male fate. In species with chromosomal sex determination, gonadal somatic cells are recognized as key determinants of germ cell fate.
View Article and Find Full Text PDFFront Cell Dev Biol
March 2024
Institute of Neuroscience, University of Oregon, Eugene, OR, United States.
The genetics of sex determination varies across taxa, sometimes even within a species. Major domesticated strains of zebrafish (), including AB and TU, lack a strong genetic sex determining locus, but strains more recently derived from nature, like Nadia (NA), possess a ZZ male/ZW female chromosomal sex-determination system. AB fish pass through a juvenile ovary stage, forming oocytes that survive in fish that become females but die in fish that become males.
View Article and Find Full Text PDFThe genetics of sex determination varies across taxa, sometimes even within a species. Major domesticated strains of zebrafish ( ), including AB and TU, lack a strong genetic sex determining locus, but strains more recently derived from nature, like Nadia (NA), possess a ZZ male/ZW female chromosomal sex-determination system. AB strain fish pass through a juvenile ovary stage, forming oocytes that survive in fish that become females but die in fish that become males.
View Article and Find Full Text PDFBiol Reprod
June 2022
Department of Biomedical Sciences and Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa, Macau 999078, China.
As a species without master sex-determining genes, zebrafish displays high plasticity in sex differentiation, making it an excellent model for studying the regulatory mechanisms underlying gonadal differentiation and gametogenesis. Despite being a gonochorist, zebrafish is a juvenile hermaphrodite that undergoes a special phase of juvenile ovary before further differentiation into functional testis and ovary. The mechanisms underlying juvenile ovary formation and subsequent gonadal differentiation remain largely unknown.
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