Evo-Devo view on the origin of the chordate

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K07174
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Evolutionary biology
• Research Institution: National Institute for Basic Biology
• Principal Investigator: Takahashi Hiroki 基礎生物学研究所, 形態形成研究部門, 助教 (40283585)
• Research Collaborator: Tominaga Hitoshi 総合研究大学院大学, 生命科学研究科・基礎生物学専攻, 大学院生
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 脊索動物 / 尾索動物 / 頭索動物 / ホヤ / ナメクジウオ / 脊索

Outline of Final Research Achievements

Chordate is well distinguished animal taxa. They have notochord as a common feature, but their sister group, echinoderms and hemichordates do not. This suggests that notochord is a novel feature gained by the chordate common ancestor. Brachyury gene is known as the master gene of notochord development, but it is also shared by non-chordate animals. In non-chordate invertebrate species, Brachyury is expressed in blastopore or stomodeum. On the other hand, typical chordates express this gene in blastopore as well as dorsal archenteron. Axial part of dorsal archenteron continues to express Brachyury gene, and differentiates into notochord. This indicates that the chordate common ancestor alternated Brachyury expression pattern, and thus acquired notochord. To understand how chordate ancestor acquired this novel expression pattern, we focus on Brachyury enhancer activity of amphioxus, the most basal chordate.

Free Research Field

進化発生生物学