Assessment of the impact of global warming on sex determination in coastal marine fish(Fostering Joint International Research)

2019 Fiscal Year Final Research Report

• Project/Area Number: 15KK0277
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research)
• Allocation Type: Multi-year Fund
• Research Field: Aquatic bioproduction science
• Research Institution: Tokyo University of Marine Science and Technology
• Principal Investigator: Yamamoto Yoji 東京海洋大学, 学術研究院, 助教 (10447592)
• Project Period (FY): 2016 – 2019
• Keywords: 地球温暖化 / 気候変動 / 指標生物 / 温度依存型性決定機構 / 遺伝型性決定機構 / 性転換 / トウゴロウイワシ

Outline of Final Research Achievements

To reveal the mechanism of low water temperature-induced female sex reversal in fish, trascriptomic analysis was performed using gonadal mRNAs from normal (XX) and low temperature-induced sex reversed (XY) females. Ninety-nine genes (e.g., egfl6, capn1, calm1) were differentially expressed between the two groups during the sex determining period. Ingenuity Pathway Analysis (IPA) to predict biological pathways that underwent changes based on observed gonadal gene expression revealed that the top-three differential canonical pathways were calcium, protein kinase A, and opioid signaling. Upstream regulator analysis, which predicts regulators that caused observed gene expression, revealed several interesting factors such as beta-estradiol, estrogen receptor 1, and transforming growth factor beta 1. The fact that estrogen and TGF-beta signaling were highlighted by IPA suggests that these pathways may play a key role in feminizing effects of cooler temperatures on XY-genotype fish.

Free Research Field

繁殖生態学

Academic Significance and Societal Importance of the Research Achievements

本課題により、低水温により魚類の遺伝的雄（XY）を雌（卵巣）に性転換させるには、estrogenおよびTGF-βシグナル系が深く関わっていることが明らかとなった。本成果は、魚類のみならず、爬虫類等の他の脊椎動物における温度依存型性決定機構の全容解明、とりわけ低水温が誘起する遺伝的雄の性転換機構の解明に寄与すると期待される。また、魚類を含む脊椎動物の性決定機構の進化を解読するうえでも重要な分子基盤になると期待される。