Genomic basis underlying adaptive differentiation in reproductive-related behavior of the stickleback fish

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02552
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 45030:Biodiversity and systematics-related
• Research Institution: Kyushu University
• Principal Investigator: Tomoyuki Kokita 九州大学, 農学研究院, 教授 (60372835)
• Co-Investigator(Kenkyū-buntansha): 平瀬 祥太朗 東京大学, 大学院農学生命科学研究科(農学部), 助教 (90635559)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 繁殖戦略 / 適応進化 / 行動生態学 / 行動遺伝学

Outline of Final Research Achievements

This study aims to elucidate the ecological genetic basis for the diversity of instinctive behavior in wild animals, using reproductive territorial behavior as a model system. Although this behavior is common in many animals, it is known that there is variation in its expression intensity among closely related species and populations within a species. In this study, we explored this question in freshwater threespine stickleback that inhabit various freshwater environments and evolved various phenotypic traits in each population. As a result, genetic variation and environment-dependent convergence in the expression intensity of the relevant behaviors between populations inhabiting different ecological environments (i.e., lentic and lotic ecotypes) were confirmed. Furthermore, various endocrinological and genomic analyses strongly suggest that the evolutionary genetic basis behind the convergence is different.

Free Research Field

生態遺伝学

Academic Significance and Societal Importance of the Research Achievements

動物の多様な本能行動の発現機構は生命科学者を魅了する現象であり、マウス等の実験モデル動物では行動発現と関連した脳機能に関わる遺伝子が次々と明らかになっている。その一方で、生物多様性科学の文脈で、遺伝子・ゲノムレベルの枠組みから野生動物に認められる行動進化を理解しよう試みは大きな挑戦であり続けている。本研究が対象とした繁殖縄張り制は動物界に広く存在する行動様式であるものの、この多様性進化の遺伝・ゲノム基盤に関する確固たる実証例はなかった。本研究は、イトヨに認められる雄の繁殖行動の種内変異を利用して、未開拓分野である野生動物における本能行動の多様化機構の一旦を描き出した先駆的な研究となった。