Evolutionary differentiation of androgen receptor responsible for sexual characteristics development

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K06741
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44040:Morphology and anatomical structure-related
• Research Institution: Kyushu University
• Principal Investigator: Ogino Yukiko 九州大学, 農学研究院, 准教授 (00404343)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: アンドロゲン / 遺伝子重複 / 多様化 / 二次性徴

Outline of Final Research Achievements

Teleost fishes exhibit complex sexual characteristics in response to androgens. However, the molecular mechanisms underlying their evolutionary acquisition remain largely unknown. To address this question, we analyzed medaka mutants deficient in teleost-specific androgen receptor ohnologs (ara and arb). We found that both ara and arb are required in males to achieve efficient reproductive success; ara and arb are functionally redundant in the regulation of courtship display but have divergent roles in other morphological and behavioral sexual characteristics. Unexpectedly, both ar ohnologs are not essential for spermatogenesis in medaka, which may have permitted the ar evolution in teleosts by reducing part of the functional constraints on the gene(s). We also demonstrated that differences in transcriptional regulation and intracellular localization could account for the divergent roles of ar ohnologs in the development of the sexual characteristics of teleosts.

Free Research Field

進化内分泌学

Academic Significance and Societal Importance of the Research Achievements

これまで、重複遺伝子群は、祖先的な役割を保ちながら、役割を新たに獲得、あるいは分担することにより、より複雑な仕組みを作り上げると理解されてきた。本研究により、祖先遺伝子が担っていた役割を大胆に捨て、かつコピー数を増やして仕事の分担を進めて特殊化していったことにより、真骨魚類の多様化と繁栄をもたらした多様な二次性徴形質が獲得されたと考えられた。魚の美しさや行動の多様化と全ゲノム重複によるアンドロゲン受容体遺伝子の重複進化との関連性を詳細に示した最初の例であり、生物の性的特徴の多様化とゲノム進化の関係を探る上で大きな一歩を示した。