Evolution from fins into limbs

2016 Fiscal Year Final Research Report

• Project/Area Number: 25291086
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Biodiversity/Systematics
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Tanaka Mikiko 東京工業大学, 生命理工学研究科, 准教授 (40376950)
• Co-Investigator(Kenkyū-buntansha): 黒川 大輔 東京大学, 理学(系)研究科(研究院), 助教 (40342779) ; 村上 安則 愛媛大学, 理工学研究科, 准教授 (50342861)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 進化発生 / 形態進化

Outline of Final Research Achievements

In this project, we aimed to explore the evolutionary process of how fins have evolved into limbs during evolution of vertebrates. Studies of catsharks revealed that there was a shift in the balance of anterior and posterior fileds in their fin buds compared to that in mouse limb buds. Furthermore, catshark genome lacked a sequence found in mice and other tetrapods, which is responsible for preventing Gli3 expression in the posterior part of tetrapod limb buds. When we deliberately “posteriorised” pectoral fin buds of catshark, the fins lost anterior skeletal elements, and showed a single bone connected to the pectoral girdle as seen in fossil Tiktaalik pectoral fins. We also explored the developmental mechanisms behind the alteration of the neuronal framework during morphological diversification of limbs and found that Sema3A-dependent guidance system plays a key role in this process.

Free Research Field

進化発生学