Sexual spectrum of fish brain

2021 Fiscal Year Final Research Report

• Project Area: Spectrum of the Sex: a continuity of phenotypes between female and male
• Project/Area Number: 17H06429
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Biological Sciences
• Research Institution: The University of Tokyo
• Principal Investigator: Okubo Kataaki 東京大学, 大学院農学生命科学研究科(農学部), 教授 (10370131)
• Co-Investigator(Kenkyū-buntansha): 中城 光琴 大阪医科薬科大学, 医学部, 助教 (60824795)
• Project Period (FY): 2017-06-30 – 2022-03-31
• Keywords: 性スペクトラム / 魚類 / 脳 / 行動

Outline of Final Research Achievements

Teleost fish are unique among vertebrates in that their sex-specific phenotypes, including behaviors, are quite labile and can even be reversed as adults. This indicates that the fish brain can transition from one end of the sexual spectrum to the other throughout their lifetime. In medaka (Oryzias latipes), we recently identified a group of neurons in the brain region implicated in mating behavior that appear and disappear in a reversible manner in response to changes in the adult sex steroid milieu. The results of this study strongly suggest that these neurons underpin the mechanisms that allow the fish brain (mating behavior pattern) to transition on the sexual spectrum and also revealed part of the molecular and cellular basis of these mechanisms.

Free Research Field

魚類生殖生理学

Academic Significance and Societal Importance of the Research Achievements

本研究は、体内のホルモン環境に応じて性スペクトラム上の位置が変わる魚類の脳に焦点を当て、魚類の脳（性行動パターン）が性スペクトラム上を大きく移動できるメカニズムの一端を明らかにした。研究をさらに進めることで、脳の性の確かさや変わりやすさの分子基盤がみえてくると期待される。魚類は生涯にわたって性転換する能力を有していることが知られており、性転換に伴って、脳の性も雌雄逆転する。本研究の成果は、未だ謎に包まれている魚類の性転換メカニズムを明らかにする糸口としても注目に値する。