Evo-devo approach on the sex differentiation mechanism in volvocine algae to reconstruct the emergence of oogamy

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06766
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45020:Evolutionary biology-related
• Research Institution: Chuo University
• Principal Investigator: HAMAJI Takashi 中央大学, 研究開発機構, 専任研究員 (10784556)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 性分化 / クラミドモナス / ボルボックス / 転写因子 / RWP-RKドメイン

Outline of Final Research Achievements

The emergence of oogamy is one of the major issues in evolutionary biology. Both metazoans, including humans, and terrestrial plants, which account for a large biomass on earth, are producing sperms and eggs with marked differences in the motility and size. It is generally believed that heterogametes and oogamy evolved from isomorphic gametes. Based on the background of the evolutionary history of sexual reproduction in the Volvox lineage of green algae, which is the only extant species among all eukaryotic lineages including isogamy and oogamy in it, the process by which derivative heterogametes emerged from ancestral-type isomorphic gametes, the entire gene regulatory network involved in the mechanism of sexual differentiation in Chlamydomonas and Volvox was investigated.

Free Research Field

性進化学

Academic Significance and Societal Importance of the Research Achievements

同型配偶クラミドモナスにおいて1994年に性決定領域ならびに1997年にマイナス・オス性決定転写因子MIDが同定されて以来じつに30年近い年月にわたり一切不明であった、ボルボックス系列緑藻の性決定にかかわる遺伝子制御の分子基盤の実体が本VSR1の発見によりついに解明されたと信ずる。この結果はむしろ今後、どのような遺伝子群の発現が「性の実質」であるかを明らかにするためのスタートラインに立つものとして位置づけうるだろう。