2016 Fiscal Year Final Research Report
Alterations of regional specifications of the jaw elements along the proximal-distal axis in the mammalian evolution
| Project/Area Number |
26440127
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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 |
Developmental biology
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| Research Institution | Nihon University |
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Principal Investigator |
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | 顎 / 単弓類 / 進化 / 異形歯性 / ほ乳類 / 歯式 / ホメオボックス / 耳小骨 |
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| Outline of Final Research Achievements |
During the evolution of mammal from ancestral synapsid, regional specifications of the jaw elements have occurred along the proximal-distal axis. In this study, expression of homeobox genes in the jaw primordium of various animals, with special focus on marsupial opossum, was examined, and the results were correlated to the dental formula. Accordingly, Msx1-BarX1 double-positive domain would give rise to the premolars in basic mammals including opossum, while mouse lower jaw primordium lacked such domain.
During mammalian evolution, the jaw joint was modified and the original joint bones were recruited to the middle ear ossicles. It has also been suggested that, in marsupial, the development of jaw joint and middle ear would recapitulate the evolutionary process. The development of jaw joint and middle ear ossicles in opossum, however, did not show such evolutionary events.
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| Free Research Field |
発生生物学、進化生物学
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