The emergence mechanisms of second and third sex-determining genes in the same medaka population driven by retrotransposon

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K06278
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45010:Genetics-related
• 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): 2021-04-01 – 2024-03-31
• Keywords: Oryzias latipes / sex-determining gene / gsdf / gain-of-function / whole genome analysis / gene expression / sex-linkage analysis

Outline of Final Research Achievements

The aim of this study was to elucidate the birth mechanism of a new sex-determining gene in the genus Oryzias, in which sex-determining genes frequently shift, using the wild population of Oryzias latipes in Nagasaki Prefecture, in which multiple sex-determining genes coexist, and the following results were obtained.
(i) Analysis of the whole genome of the Nagasaki population revealed that the retrotransposon responsible for the second sex-determining gene, GsdfneoY, has high transfer activity within the population, and experiments on the gain of function by GsdfneoY mRNA revealed its functional timing.
(ii) The functional timing of the third sex-determining gene that turns individuals with GsdfneoY female from gene expression and histological analysis, and the multiple loci where the third sex-determining gene is present from sex linkage analysis.

Free Research Field

遺伝学

Academic Significance and Societal Importance of the Research Achievements

本研究の学術的意義は、性決定遺伝子の交代機構の解明にある。長崎県のミナミメダカ個体群をモデルに、性決定遺伝子がどのように誕生したかの一端を明らかにした。特に、GsdfneoY遺伝子の発現が性決定に重要な役割を果たし、内在性レトロウイルスSushi-ichiの転移がこのプロセスを駆動していることを示した。この成果は、性決定の多様性と進化を理解する上で重要な知見を提供する。
社会的意義として、性決定メカニズムの理解が生物多様性の保全や種の存続に寄与できるさらに、魚類の性決定メカニズムの解明は、養殖業における性制御技術の開発にも貢献する可能性がある。