| Project/Area Number |
16K07483
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Biodiversity/Systematics
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
広瀬 慎美子 東海大学, 海洋学部, 特任准教授 (10398307)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000)
Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2017: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Keywords | ホヤ / 分子系統 / 光共生 / 藍藻 / 進化 / 多様性 / 共生 / 系統 |
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| Outline of Final Research Achievements |
Cyanobacterial symbiosis in some colonial ascidians of the four genera in the family Didemnidae is the only obligate-symbiosis system between the chordates and photosynthetic organisms. We examined the molecular phylogeny of didemnid ascidians including non-symbiotic and symbiotic species belonging to six didemnid genera. The phylogenetic tree supports the monophyly of Diplosoma, while photosymbiotic species of Trididemnum were separated into four discrete clades. We mapped the modes of symbiosis (e.g., cyanobacterial species, distribution pattern on the phylogenetic tree to elucidate the evolutionary history of this symbiosis system. The present results supported that 1) cyanobacterial symbiosis was independently established in multiple times within Didemnidae, 2) similar modes of symbiosis were convergently evolved in discrete genera and/or clades.
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| Academic Significance and Societal Importance of the Research Achievements |
サンゴやシャコガイなど光合成生物と共生することによって効率の良い代謝系システムを獲得している動物が様々な分類群で知られているが、共生システムの進化・多様化についてはわかっていないことが多い。本研究では我々を含む脊索動物では唯一の光合成共生系であるホヤと藍藻について、宿主ホヤの系統と共生様式の多様性から、共生系の進化・多様化過程を推定することができた。これにより、なぜ脊索動物においてはジデムニ科ホヤにおいて『だけ』繰り返し藍藻との共生成立が生じたのかという問題が新たに提起される。
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