Taxonomic studies on novel discobids for more precise understanding of their diversity and the form ancestral eukaryotic cell.

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K06792
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45030:Biodiversity and systematics-related
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: Yabuki Akinori 国立研究開発法人海洋研究開発機構, 地球環境部門(海洋生物環境影響研究センター), グループリーダー (20711104)
• Co-Investigator(Kenkyū-buntansha): 白鳥 峻志 筑波大学, 生命環境系, 助教 (70800621) ; 石田 健一郎 筑波大学, 生命環境系, 教授 (30282198)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 系統分類 / 多様性 / 微細構造 / 原生生物

Outline of Final Research Achievements

The strain YPF-PP, which was one of the main targets in this research project, was identified as an undescribed species belonging to a novel subphylum in Discoba by molecular analyses and morphological observation. The strain YPF1504 was described as a new species in Apusomonadida, which was also one of the early branching eukaryotic lineages. It had been suggested as a member of Discoba in the initial observation, but it tuned out that it was an apusomonad. The large-scale phylogenetic analysis was conducted to understand the phylogenetic position of Diuscoba as well as the whole eukaryotic relationship, and based on this result, a novel eukaryotic assembly was proposed. A novel narnavirus was also detected and reported from the one protist strain that was established in this research project.

Free Research Field

進化原生生物学

Academic Significance and Societal Importance of the Research Achievements

確立した培養株を用いた系統分類学的研究から、人類および地球という惑星における資源・資産である生物多様性に関する情報を更新する成果を創出することができた。特に、YPF-PP株に関する研究で把握した鞭毛周辺構造とその近縁生物種との比較からは、それらの特徴が真核生物進化の初期から存在していた可能性を見出した。これらの知見は、地球史における一大未解明事案である真核生物の初期進化、特に祖先真核細胞の姿形に迫る成果となっている。そこから、生物の多様性や進化のより正確な理解に貢献するだけでなく、真核細胞が元来有していた機能に関する理解の深化にも貢献するに至った。