| Project/Area Number |
16K18594
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Evolutionary biology
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| Research Institution | Hyogo Medical University |
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Principal Investigator |
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| Research Collaborator |
HIGUCHI Shinnosuke
KURATANI Shigeru
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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 |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2016: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Keywords | 半規管 / 内耳 / ヤツメウナギ / ヌタウナギ / 発生 / 進化 / 円口類 / Otx1 / 形態進化 |
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| Outline of Final Research Achievements |
In this study, we successfully observed the developing inner ears of the inshore hagfish Eptatretus burgeri as well as lamprey Lethenteron camtschaticum, and compared them at histological and molecular levels. We found that both hagfish and lampreys have developmental patterning for anterior and posterior canals similar to the early developmental pattern of the inner ear in gnathostomes. In addition, we found another sensory epithelium and axon bundles in both cyclostome species, which are thought to be homologous to the gnathostome lateral crista. We suggest that the latest common ancestors of the extant vertebrates already have had more complex inner ears than previously thought.
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| Academic Significance and Societal Importance of the Research Achievements |
人間が人間について知りたいというのは人類普遍の知的好奇心のひとつである。われわれヒトの複雑なからだは、どのような進化を経て成立したのだろうか？三半規管はわれわれの平衡器官として大変重要な構造物で、めまいなどを伴う疾病にも関連の深い器官である。複雑な形態を持つ半規管の進化の過程は、これまで謎に包まれていたが、一半規管から一つずつ数を増やしてきたと単純に理解されてきた。ところが今回の我々の研究で、実際の進化はそう単純なものではなく、共通祖先の段階で多くの三半規管の構成要素をすでに持っていることがわかった。
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