Parallel Adaptation and the limit of local adaptation in environments with gene flow

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06822
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45040:Ecology and environment-related
• Research Institution: Chiba University
• Principal Investigator: Takahashi Yuma 千葉大学, 大学院理学研究院, 准教授 (00707622)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 潮汐リズム / 内在リズム / チリメンカワニナ / 遺伝子流動

Outline of Final Research Achievements

In rivers, since the tidal influence is strong in estuarine areas, adaptation to the tidal cycle is required to expand the distribution from upstream to downstream. On the other hand, if there is gene flow between adjacent environments, local adaptation is expected to be difficult, especially in downstream population. The distribution of the freshwater snail, Semisulcospira reiniana, has spread to the tidal zone in some rivers. In the present study, we first showed that only individuals of the tidal population exhibited a circatidal rhythm in their activity. However, the exposure to tidal cycle induced an activity rhythm with an approximately 12-hour cycle in individuals of both tidal and non-tidal population. This suggests that plasticity in response to environmental cycles led to the adaptation to the tidal cycle.

Free Research Field

進化生態学

Academic Significance and Societal Importance of the Research Achievements

内在リズムは、多くの生物が有する基本的かつ普遍的な表現型である。本研究は、このリズムが種内で変化しうることを示した。異なった内在リズムの獲得は、生物がことなる環境リズムの場所に分布を拡大するさいにもっとも重要な形質変化の一つである。本研究では、行動変化のみならず、その遺伝基盤にもアプローチできた点で、生態学や進化生物学、あるいはその関係分野に大きなインパクトを与えるものである。