The study of the universal evolutionary mechanism of the sex-determining gene by analyzing three medaka species whose sex-determining gene is Gsdf.

• Project/Area Number: 17K15161
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Genetics/Chromosome dynamics
• Research Institution: University of Shizuoka
• Principal Investigator: Myosho Taijun 静岡県立大学, 食品栄養科学部, 助教 (00781808)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2017: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: Gsdf / sex-determining gene / LTR retrotransposon / Oryzias latipes / Oryzias luzonensis / Oryzias pectoralis / 性決定遺伝子 / ミナミメダカ / Sushi-ichi / メダカ属 / 遺伝学 / 遺伝子 / 進化

Outline of Final Research Achievements

In the genus Oryzias, the sex-determining gene (SD gene) were frequently changed The purpose of this study was to clarify the universal evolutionary mechanism of the SD gene by analyzing three medaka species whose SD gene is Gsdf.
In Oryzias latipes from Nagasaki population, the SD gene GsdfneoY was appeared by the insertion of the LTR retrotransposon in the upstream region of Gsdf. Furthermore, the SD gene took over the existing SD cascade by acquiring autonomous high expression independent of the old SD gene Dmy. Although the other two species have different responsible sequences of SD gene, these SD genes utilize existing SD cascades. These results suggested a common molecular mechanism for the appearance of the SD gene.

Academic Significance and Societal Importance of the Research Achievements

脊椎動物において10以上の性決定遺伝子が同定され、その多様性が明らかになっている。しかし、それぞれの性決定遺伝子は誕生後長い年月が経過しており、新規性決定遺伝子誕生の詳細な分子機構の特定が困難なため、なぜそのような多様性が生み出されるのかが不明だった。
本研究では、進化的に新しいメダカ属3種の性決定遺伝子Gsdfのそれぞれ誕生の分子機構を明らかにすることで、脊椎動物には多様な性決定遺伝子があるが、普遍的な性決定カスケードの存在という共通性のもとにその多様性が生み出された可能性を示唆した。

Research Products

• [Journal Article] Inter- and intraspecific variation in sex hormone induced sex-reversal in medakas, Oryzias latipes and Oryzias sakaizumi (2019)
  • Author(s): Myosho, T., Sato, T., Nishiyama, H., Watanabe, A., Yamamoto, J., Okamura, T., Onishi, Y., Fujimaki, R., Hamaguchi, S., Sakaizumi, M. and Kobayashi, T
  • Journal Title: Zoological Science Volume: 36 Issue: 5 Pages: 425-431
  • DOI: 10.2108/zs180194
  • Peer Reviewed
• [Presentation] 新旧性決定遺伝子DmyとGsdfneoYが共存する長崎県平戸産野生ミナミメダカ個体群 (2019)
  • Author(s): 明正大純、小林亨
  • Organizer: 第67回日本生態学会大会