Diversification of the sex-determination cascade created by the struggle between symbiotic bacteria and their hosts

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K19166
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 39:Agricultural and environmental biology and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Suzuki Masataka 東京大学, 大学院新領域創成科学研究科, 准教授 (30360572)
• Co-Investigator(Kenkyū-buntansha): 中 秀司 鳥取大学, 農学部, 准教授 (00443846)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: 性決定 / 性分化 / 雄決定遺伝子 / 雌決定遺伝子 / piRNA / W染色体 / マイマイガ / embryonic RNAi

Outline of Final Research Achievements

This study has revealed that the female and male determinants of the sponge moth, Lymantria dispar, which have been a mystery for more than a century, are Fet-W and LdMasc, respectively, and that Fet-W produces piRNAs that target LdMasc, which in turn degrades LdMasc mRNA, thereby suppressing male differentiation in females. and that female differentiation is achieved by suppressing LdMasc mRNA. By carrying out analyses on wild-region populations of the sponge moth, we found regional differences in Fet-W copy number and its expression. Similar regional differences were also found for LdMasc. We also found a number of genes on the W chromosome derived from LdMasc, and obtained evidence suggesting that they may function as female-determining genes.

Free Research Field

性差生物学・分子生物学・遺伝学・発生学

Academic Significance and Societal Importance of the Research Achievements

本研究によりマイマイガの性決定遺伝子には種内多型がみられることが分子レベルで解明された。この発見は、性決定機構に驚異的な多様性が生まれる仕組みを理解する上で重要な手がかりを与える。また、性決定遺伝子の多型は性決定能の多型を生み出し、その結果異なる地域集団の交配が性転換をもたらす事例を発見した。この発見は、性決定機構が多様性を示す適応的意義の理解に繋がる。本研究により、雄決定遺伝子から派生したW染色体上の遺伝子が雌決定能を有する可能性が見出された。本発見は、雄決定遺伝子から派生した遺伝子が新たに雌決定遺伝子としての機能を獲得する進化のプロセスを理解する上で重要な手がかりとなる。