2023 Fiscal Year Final Research Report
Adaptative implication of chromosome fusion in Drosophila karyotype evolution
| Project/Area Number |
21K19299
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 45:Biology at organismal to population levels and anthropology, and related fields
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
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| Project Period (FY) |
2021-07-09 – 2024-03-31
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| Keywords | ネオ性染色体 / 染色体融合 / 進化確率法 / 自然選択 / 実験進化 / 病原変異予想 / 集団ゲノム解析 |
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| Outline of Final Research Achievements |
The number of chromosomes changes during eukaryotic evolution, resulting in differences between closely related species and within species. To clarify the adaptive significance of such evolutionary changes, we (1) improved the evolutionary probability method, which can detect natural selection at the nucleotide site level over the entire genome, to be applicable without a molecular phylogenetic tree, and (2) used the experimental evolutionary approach to try to reproduce the evolutionary process of neo-X and neo-Y chromosomes in Drosophila albomicans, each of which arose from a fusion of a sex chromosome and an autosome and increased in frequency to become fixed in the population. As a result, we were able to improve the evolutionary probability method to be superior to the original method in terms of both accuracy and computational time. On the other hand, we did not succeed in reproducing the evolutionary process of neo-sex chromosomes using an experimental population.
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| Free Research Field |
分子進化遺伝学
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| Academic Significance and Societal Importance of the Research Achievements |
染色体数の適応的意義はゲノム進化を理解する上で基本的な問いであるが、未だよく分かっていない。その理由として、遺伝子領域のみならずゲノムワイドに自然選択を検出する方法が確立していないことが上げられる。本研究で用いた進化確率法はゲノムの全ての塩基座を対象にすることが可能であるが、推定精度が使用する系統樹に強く依存するため、信頼性が限られる。本研究では、系統樹の代わりに配列間距離の共分散行列を使うことで進化確率法を改良した。その結果、推定精度、計算速度の両面で従来の方法を上回ることに成功した。この方法を適用することでゲノムにはたらく多様な自然選択が検出可能となり、疾病関連座位の予測にも利用できる。
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