2022 Fiscal Year Final Research Report
A new function of Shh signaling to control epithelial actomyosin contractility during tooth morphogenesis
| Project/Area Number |
19K10047
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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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| Review Section |
Basic Section 57010:Oral biological science-related
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| Research Institution | Kagoshima University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
中富 満城 産業医科大学, 産業保健学部, 准教授 (10571771)
大峡 淳 新潟大学, 医歯学系, 教授 (40266169)
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Keywords | 歯 / 哺乳類 / トガリネズミ / 発生 / 進化 / 反復 / 遺伝子発現 |
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| Outline of Final Research Achievements |
Phylogenetically, the tribosphenic molars, prototypes of multi-cusped cheek teeth in mammals, are derived from the single-cusped conical teeth of reptiles through the addition of cusps. Ontogenetically, mammalian molars are formed through the interface between the dental epithelium and mesenchyme becoming geometrically complex by adding signaling centers, the enamel knots. To re-evaluate cusp homologies in Mesozoic mammals from an ontogenetic perspective, this study tracked molar development in the modern house shrew (Suncus murinus), whose molars are morphologically the least derived from tribosphenic prototypes. The development of house shrew molars proceeded as if it replayed the evolutionary process of tribosphenic molars in Mesozoic mammals. The parallel relationship between ontogeny and phylogeny of mammalian molars, if any, suggests that heterochronic changes during tooth development should have been causal factors for the evolutionary transformation of tooth morphology.
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| Free Research Field |
歯の発生と進化
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| Academic Significance and Societal Importance of the Research Achievements |
進化的観点からは、多咬頭の臼歯は、単咬頭の円錐歯に咬頭が付加されることで長い地質学的時間をかけて進化してきた。一方、発生的観点からは、胎生期の数日の間に、エナメル結節が次々に形成されることで、その位置に咬頭が形成され、多咬頭歯が完成する。発生過程（個体発生）が、進化過程（系統発生）を反復するのか否か、は進化生物学における大きな未解決問題である。本研究は、現生哺乳類の臼歯の発生過程が、化石哺乳類の臼歯の進化過程を反復するように進行することを明らかにしただけでなく、その並行性を生み出すメカニズムに関する示唆を与える。
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