Elucidation of the Initial Dissemination Process of Ginkgo in Japan

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K20714
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 3:History, archaeology, museology, and related fields
• Research Institution: Chiba University
• Principal Investigator: Uehara Koichi 千葉大学, 大学院国際学術研究院, 教授 (20221799)
• Project Period (FY): 2020-07-30 – 2024-03-31
• Keywords: イチョウ

Outline of Final Research Achievements

Ginkgo (Ginkgo biloba) was once distributed worldwide but later declined and became extinct in Japan at the end of the Pleistocene. The ginkgo that survived in southwestern China is believed to have spread throughout Japan along with culture after the Heian period, although the exact process of dissemination remains unclear. Due to such biological and cultural backgrounds, research has been conducted on the introduction and dissemination routes of ginkgo in Japan. In this study, comprehensive genetic analysis was conducted on giant ginkgo trees with a trunk circumference of over 8 meters distributed in Japan using the latest RAD-seq analysis with next-generation DNA sequencers. A total of 269 samples were analyzed to examine the dissemination process of ginkgo, including detailed dissemination routes of individual trees.

Free Research Field

生物学

Academic Significance and Societal Importance of the Research Achievements

イチョウは最も原始的な性質を残した「生きた化石」のひとつで、人々に親しまれる植物である。現存するイチョウは中国原産で、平安時代ごろに日本に伝搬したと考えられ、人の手で日本中に広まった。日本は、早くに伝搬したことから、世界に広まったイチョウの伝搬を考える上で重要な位置にあり、また国内に多くの「巨木」が現存していることから、国内への伝搬を探ることも可能で、当時の人々の仏教とも絡んだ移動を考察する上でも重要である。本研究は国内のイチョウ巨木を網羅的にサンプリングし、その個体間の系統関係を明らかにするもので、最新の生物科学的技術や解析を用いて、歴史・文化史への貢献をめざすもので社会的意義も大きい。