| Project/Area Number |
10044201
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied animal science
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| Research Institution | NAGOYA UNIVERSITY |
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Principal Investigator |
SHIMADA Kiyoshi Nagoya University, Graduate School of Bioagricultural Sciences, Professor, 大学院・生命農学研究科, 教授 (40065579)
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| Co-Investigator(Kenkyū-buntansha) |
HARADA Nobuhiro Fujita Health University, School of Medicine, Professor, 医学部, 教授 (00189705)
PARK Min kyun University of Tokyo, Graduate School of Science, Assistant Professor, 大学院・理学系研究科, 助教授 (00228694)
TOMOGANE Hiroshi Nippon Veterinary and Animal Science University, Department of Animal Sciences, Professor, 獣医畜産学部, 教授 (30023493)
SAITO Noboru Nagoya University, Graduate School of Bioagricultural Sciences, Assistant Professor, 大学院・生命農学研究科, 助教授 (40211924)
ONO Tamao Shinshu University, School of Agriculture, Assistant Professor, 農学部, 助教授 (10177264)
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| Project Period (FY) |
1998 – 2000
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| Keywords | chicken embryo / mRNA / sexual differentiation / Dmrt-1 / AMH / Sf-1 / Dax-1 / Sox-9 |
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| Research Abstract |
Since sex determination and differentiation mechanisms remain unsolved in birds, this project was conducted to elucidate the molecular mechanisms of sexual differentiation of the chicken gonad. The testis produces anti-Mullerian hormone (AMH) and androgen, whereas the ovary produces little AMH but produces estrogen predominantly. Our in situ hybridization study demonstrated that AMH mRNA was expressed as early as day 5 of incubation followed by a sharp increase on day 6 of incubation in males, which was subsequently maintained. In contrast, the female showed minimum levels of expression. Conversely, aromatase mRNA was expressed in the gonad as early as day 6 of incubation in female but little in the male. Possible transcription factors affecting the AMH and aromatase genes include Sox 9, Sf-1, Dax-1, and Dmrt-1. Sox 9 mRNA is predominantly expressed in male gonad, although it is expressed after the expression of AMH.The Sf-1 mRNA expression is sexually dimorphic after day 7.5 of incubation and expression is higher in the female gonad than in the male gonad. In the chicken Dax-1 mRNA is expressed in the chicken gonad in both sexes. Chicken Dmrt-1 gene on the Z chromosome was expressed in the genital ridge and Wolffian duct prior to sexual differentiation and is expressed at higher levels in male than in female embryos. Furthermore, this is expressed prior to AMH expression in male. This sex- and time-specific expression makes this gene an especially good candidate to be involved in avian sex determination.
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