Experimental evolution of neo-sex chromosomes

• Project/Area Number: 16K14792
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Evolutionary biology
• Research Institution: National Institute of Genetics
• Principal Investigator: Kitano Jun 国立遺伝学研究所, ゲノム・進化研究系, 教授 (80346105)
• Co-Investigator(Kenkyū-buntansha): 山平 寿智 琉球大学, 熱帯生物圏研究センター, 教授 (20322589)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000); Fiscal Year 2018: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000); Fiscal Year 2017: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2016: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
• Keywords: 性染色体 / 進化 / メダカ

Outline of Final Research Achievements

In two independent lines, sex conversion to males occurred frequently at high temperature treatment (32 °C). Analysis of changes in the sex conversion rates among 4 generations showed that the pattern of generational change was quite different between the two lines. In one line, the sex conversion rate at 26 °C was constant regardless of generation, while the sex conversion rate at 32 °C showed fluctuation. In the other line, the sex conversion rate was relatively constant at 32 °C, while the sex conversion rate at 26 °C showed a large fluctuation. Thus, we obtained materials for analyzing neo-sex chromosomes and clarified generational changes in the sex conversion rates.

Academic Significance and Societal Importance of the Research Achievements

性決定機構や性染色体がどの程度ゆらぐのか、また、潜在的に性を決める遺伝子座がどの程度ゲノム内に隠れているのかを明らかにするのが本研究の目的である。我々は、青森の野外メダカの性決定が温度によって大きく揺らぐこと、世代を経て変動することを明らかにした。本結果で得られたY染色体の除去系統の個体のDNAを解析することによって、性を決める潜在的遺伝子座を同定することができる。