Reconstruction of ancient ecosystems using sediment core environmental DNA

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K19876
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 64:Environmental conservation measure and related fields
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: HOSHINO Tatsuhiko 国立研究開発法人海洋研究開発機構, 超先鋭研究開発部門(高知コア研究所), 主任研究員 (30386619)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 環境DNA / 堆積物 / 古代生態系

Outline of Final Research Achievements

DNA was extracted from sediments (up to 4 m deep) from six sites in Uranouchi Bay, Kochi Prefecture, Japan, which are coastal sediments, and amplicon sequencing of the 18S rRNA gene and COI gene was performed. The results showed that although many current organisms were detected in the surface layer, many DNAs from terrestrial plants were detected in sediments deeper than 150 cm, suggesting that these DNAs are likely to reflect past vegetation. Analysis of 18S rRNA in 300 marine sediments from around the world from deeper sediments (maximum depth 650 m below the seafloor) showed that eukaryotic DNA is widely preserved in sediments less than 100,000 years old. DNA from freshwater diatom species was also detected in sediments from glacial freshwater lakes in the Baltic Sea, suggesting that environmental DNA analysis can be used to reconstruct ancient ecosystems.

Free Research Field

微生物生態学、環境生態学、地球微生物学

Academic Significance and Societal Importance of the Research Achievements

海の底の泥には過去に地球上に存在した生物のDNAの一部が分解されずにそのまま残っていることが知られている。本研究では、これらのDNAが過去の地球の生態系を理解するためのツールとして使用できるかどうかを調査した。その結果、泥の深い部分で植物のDNAが検出されることが示された。また、バルト海の堆積物では氷河期に生息していた藻類のDNAが海底の堆積物から検出され、堆積物中のDNAが古代の生物相を理解するために利用可能であることがわかった。