Evolutionary Ecological Origins of Interspecific Asymmetry in Reproductive Isolation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15160
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 45040:Ecology and environment-related
• Research Institution: Hokkaido University
• Principal Investigator: Yamaguchi Ryo 北海道大学, 先端生命科学研究院, 助教 (80812982)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 種分化 / 生殖隔離 / 生物地理 / 数理モデル

Outline of Final Research Achievements

In the initial stages of local adaptation to a new environment, most individuals have low fitness, the population size is small, but as adaptation progresses, the population size recovers. Classically, population size is assumed to be constant, but in this study, we have constructed a model that explicitly considers population dynamics. We have named the theory that the rate of evolution of reproductive isolation is accelerated under the high risk of extinction as the 'phoenix hypothesis of speciation'. Furthermore, mating experiments and genome analysis using Chrysolina angusticollis populations in Hokkaido, Japan, revealed that the composition of cuticular hydrocarbons, which are involved in mating preferences, have become differentiated. Asymmetric pre-mating isolation was also detected, and its origin was suggested to be due to the historical population dynamics of the parental populations.

Free Research Field

数理生物学

Academic Significance and Societal Importance of the Research Achievements

本課題では、親集団の絶滅リスクを考慮した種分化メカニズムを数理モデリングにより解析し、野外と実験下での実証データを得ることで、交配前隔離の進化的起源の理解を目指した。種分化は新たな種を生み出すメカニズムであり、継続的に種分化が繰り返されることで生物多様性が創出・維持されている一方、その背後には集団の絶滅リスクが進化を促進する可能性が明らかとなった。‘種分化の不死鳥仮説’は従来の古典的な種分化モデルでは到達できなかった知見であると同時に、今後の更なる実証研究が待たれる。