| Project/Area Number |
17H01445
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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 | 一般 |
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| Research Field |
Evolutionary biology
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
和多田 正義 愛媛大学, 理学部, 研究員 (00210881)
野澤 昌文 東京都立大学, 理学研究科, 准教授 (50623534)
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| Project Period (FY) |
2017-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥42,120,000 (Direct Cost: ¥32,400,000、Indirect Cost: ¥9,720,000)
Fiscal Year 2020: ¥10,270,000 (Direct Cost: ¥7,900,000、Indirect Cost: ¥2,370,000)
Fiscal Year 2019: ¥10,270,000 (Direct Cost: ¥7,900,000、Indirect Cost: ¥2,370,000)
Fiscal Year 2018: ¥14,170,000 (Direct Cost: ¥10,900,000、Indirect Cost: ¥3,270,000)
Fiscal Year 2017: ¥7,410,000 (Direct Cost: ¥5,700,000、Indirect Cost: ¥1,710,000)
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| Keywords | 低温耐性 / 低温順化 / 人為選択 / 実験進化 / 既存変異 / 柔らかい選択的一掃 / ショウジョウバエ / 集団遺伝 / ゲノム解析 / 適応進化 / 環境適応 / ゲノム / 進化 / 自然選択 |
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| Outline of Final Research Achievements |
In the traditional view, organismal evolution occurs by a newly emerged mutant gene taking over the preexisting gene by natural selection. In this case, we hardly explain rapid adaptive evolutions, as considerable time expected. In this research project, using a fruit fly species, Drosophila albomicans, which migrated from tropical Southeast Asia to Japan during the 1980s, we investigated the evolutionary mechanism of the rapid cold adaptation. We used an artificial selection of cold tolerance in experimental populations to examine the genome-wide gene frequency changes by the artificial selection and compare them with those observed in the natural population in Japan. In conclusion, we could explain the evolutionary changes of gene frequencies observed in both experimental and natural populations by the "soft selective sweep from standing genetic variation" model. Furthermore, we identified a genomic region as the target of natural selection.
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| Academic Significance and Societal Importance of the Research Achievements |
伝統的な生物進化のメカニズムは、集団中に生じた突然変異に自然選択が作用して集団中の遺伝子が置き換わり生物の表現型が変化するというもので、その場合、ゲノム中、選択の対象となった遺伝子周辺の多様性が著しく低下する“硬い選択的一掃”が生じる。しかし、このモデルではある程度の進化時間が必要とされ、急進的な適応進化は説明しにくい。そこで近年、既存の遺伝的変異に自然選択が作用する“柔らかい選択的一掃”のモデルが提唱されたが、自然集団のゲノム解析では検出しにくい。本研究の最大の成果は、実験集団を併用することによって柔らかい選択的一掃が検出できることを示したことで、進化生物学上の意義がある。
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