Technological development for producing all-female populations in Japanese flounder.

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05740
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40030:Aquatic bioproduction science-related
• Research Institution: Fisheries Research and Education Agency
• Principal Investigator: Toshiya Yamaguchi 国立研究開発法人水産研究・教育機構, 水産技術研究所(南勢), 主任研究員 (70604312)
• Co-Investigator(Kenkyū-buntansha): 北野 健 熊本大学, 大学院先端科学研究部(理), 教授 (40336219)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: ヒラメ / 全雌生産技術 / 性分化 / 環境依存的性決定 / ゲノム編集 / amhr2

Outline of Final Research Achievements

The Japanese flounder (Paralichthys olivaceus)is a marine fish with an XX/XY sex determination system. In aquaculture, female flounders are more productive due to their faster growth compared to males. However, producing all-female populations has been challenging because genetically female flounders can turn into phenotypic males when larvae are raised at high water temperatures. In this study, to produce a flounder strain that is all-female and resistant to masculinization at high temperatures, we created a mutant of amhr2, the receptor for amh (the sex-determining gene in flounders), using the CRISPR/Cas9 system. Consequently, the loss of function of the amhr2 gene caused sex reversal from male to female in genetically male, preventing masculinization rearing at high water temperatures. This study successfully developed a flounder strain capable of consistent all-female production, avoiding masculinization due to high water temperatures.

Free Research Field

魚類繁殖生理

Academic Significance and Societal Importance of the Research Achievements

本研究で実施したamhr2 KOヒラメの作出と解析により、amhr2を介した雄化のシグナルは生殖腺の雌化において重要なエストロゲン合成を抑制する役割があることが確認された。このことは、未だ不明な部分が多い魚類の性分化や温度依存性性決定の解明に繋がる学術的な成果と言える。また、作出したamhr2 KO系統は高水温で雄化しない完全なヒラメ全雌生産が可能であり、ヒラメ養殖において成長の良い雌だけを生産することは生産量の増加が期待できることから、社会的に意義のある成果と言える。