Analysis of the evolutional origin of the horizontal semicircular canal using cyclosotomes

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K06794
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45020:Evolutionary biology-related
• Research Institution: Hyogo Medical University
• Principal Investigator: Sugahara Fumiaki 兵庫医科大学, 医学部, 准教授 (00611005)
• Co-Investigator(Kenkyū-buntansha): 樋口 真之輔 神戸大学, 附属学校部, 附属中等教育学校教諭 (20847131)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 円口類 / 半規管 / ヤツメウナギ / ヌタウナギ / 進化 / 発生

Outline of Final Research Achievements

To investigate the developmental mechanism by which the horizontal semicircular canal is acquired, we successfully extracted RNA from lamprey embryonic inner ears that do not possess the horizontal canal. Expression analysis using the extracted RNA revealed the expression of four Otx genes, which are potential candidates corresponding to the "master control gene" of the horizontal canal, in the lamprey inner ears. We also extracted the inner ear and obtained RNA from Otx1 knockout mouse embryos lacking the horizontal canal, and their expression profiles were obtained through RNAseq. We plan to explore the acquisition process of the horizontal canal by comparing the data from both mice and lampreys.

Free Research Field

進化発生学

Academic Significance and Societal Importance of the Research Achievements

人間が自身について知りたいとい欲求は普遍的な知的好奇心のひとつである。われわれヒトはどのような進化の変遷を経て成立したのだろうか？３つの半規管は平衡感覚のうち、特に回転覚を知覚するための重要な器官である。前回の研究課題から引き続いて行ってきた研究から、複雑な形態ををもつ３つの半規管は、脊椎動物の進化の過程でいきなり成立したのではなく、段階的に成立してきたことが明らかになりつつある。