2022 Fiscal Year Final Research Report
Molecular mechanisms of fish spawning migration: testing the olfactory imprinting hypothesis
| Project/Area Number |
19K22462
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 45:Biology at organismal to population levels and anthropology, and related fields
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| Research Institution | Kobe University (2020-2022)
Research Institute for Humanity and Nature (2019) |
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Principal Investigator |
Okuda Noboru 神戸大学, 内海域環境教育研究センター, 教授 (30380281)
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| Co-Investigator(Kenkyū-buntansha) |
上原 佳敏 総合地球環境学研究所, 研究部, 研究員 (10759442)
小北 智之 九州大学, 農学研究院, 教授 (60372835)
大久保 卓也 滋賀県立大学, 環境科学部, 教授 (60280814)
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| Project Period (FY) |
2019-06-28 – 2023-03-31
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| Keywords | 産卵回遊 / 母田回帰 / 嗅覚記憶 / 階層的ナビゲーション仮説 / 耳石 / ストロンチウム安定同位体 / RNAseq / ニゴロブナ |
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| Outline of Final Research Achievements |
We demonstrated that Carassius buergeri grandoculis, which is a migratory crucian carp endemic to Lake Biwa, can perform spawning migration to the natal rice paddy. We conducted laboratory experiments to test if olfactory memory functions as mechanisms for its homing behavior, using experimental fishes which were reared in a rice paddy for 3 weeks and then grown into adults in the outdoor pond with lake water for 3 years to simulate its migratory life. The fish preferred to odors of natal rice paddy, conspecifics and compatriots, and their preferences were affected by the order of odor exposure, supporting the hierarchical navigation hypothesis. RNAseq revealed that many genes, e.g., those encoding olfactory receptors and related to the development of olfactory neurons, olfactory learning, and kin imprinting and recognition, were upregulated in olfactory nerve system and telencephalon of juveniles and spawning adults in the migratory species compared to non-migratory sister species.
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| Free Research Field |
生態科学
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| Academic Significance and Societal Importance of the Research Achievements |
サケ科魚類は大海から母川回帰するために、嗅覚記憶に基づいて複数の環境情報を手がかりに出生地まで階層的にナビゲーションすることが知られている。本研究は、サケ科魚類とは独立に進化したコイ科魚類が類似の産卵回帰メカニズムを有することを実証した。また、同科のモデル生物であるゼブラフィッシュや回遊性サケ科魚類で報告される嗅覚記憶に関連した遺伝子がニゴロブナの嗅覚・脳神経組織でも高発現することを明らかにした。さらに、耳石ストロンチウム安定同位体分析を用いて、地域集団の母田回帰率を調べる手法を確立した。一連の研究成果は、絶滅が危惧される本魚の保全活動を促進し、活動が回帰率に及ぼす効果を検証するのに役立つ。
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