2021 Fiscal Year Final Research Report
Researches on global patterns of speciation rates and sexual selection pressure in the family Adrianichthyidae
| Project/Area Number |
17H01675
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Ecology/Environment
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
北野 潤 国立遺伝学研究所, ゲノム・進化研究系, 教授 (80346105)
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| Project Period (FY) |
2017-04-01 – 2021-03-31
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| Keywords | 種分化 / 性淘汰 / メダカ |
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| Outline of Final Research Achievements |
Why is the tropics so diverse? In this study, we empirically answer this question, using medaka fishes (Adrianichthyidae) as a model system. First, estimation of the comprehensive species-level phylogeny and comparisons of their sexual dimorphisms revealed that the degree of sexual dimorphisms is negatively correlated with latitudes. Second, seasonal appearance patterns of mature individuals of a tropical species (Oryzias woworae) by semi-monthly samplings from Muna Island, Indonesia, revealed that operational sex ratios are largely male-biased in the tropics where seasonality is lacking. These results indicate that sexual selection pressures are stronger in the tropics than in the temperate zone. The stronger sexual selection pressures may promote speciation rates in the tropics, resulting in the high species diversity.
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| Free Research Field |
進化生態学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究は，性淘汰圧が緯度に沿って大きく変化することを野生集団で示した，世界初の例である．「強い性淘汰圧が種分化を促進するが故に熱帯の多様性は高い」とする結論は，「生物多様性のグローバルパターンの研究」と「性淘汰による種分化の研究」というこれまで独立に発展してきた２つの研究トレンドを１つにまとめた，革新的なアイデアである．また本研究の成果は，「新種のゆりかご」たる熱帯地域の破壊が将来に渡る生物進化に致命的な影響を与えかねないことを示すものでもあり，学術的のみならず社会的な意義も非常に大きい．
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