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エンドシンビオティック起源と真核遺伝子の差異的喪失
Chuan Ku1, Shijulal Nelson-Sathi1, Mayo Roettger1
1Institute of Molecular Evolution, Heinrich-Heine University, 40225 Düsseldorf, Germany.
Nature
|August 20, 2015
まとめ
クロロプラストやミトコンドリアのような真核細胞の起源は,細菌からのエピソード的遺伝子転送を含んでいる. ほとんどの真核生物の遺伝は垂直であり,連続した横向的な遺伝子転送による長期的な影響は限られている.
科学分野:
- 進化生物学
- ゲノミクス
- 細胞生物学
背景:
- クロロプラストとミトコンドリアは,それぞれエンドシンビオティックなシアノバクテリアとプロテオバクテリアから生まれた.
- これらの臓器細胞はプロカリオット生化学を保持しているが,大部分のタンパク質は核遺伝子によってコード化され,ゲノムが縮小されている.
- エンドシンビオティック理論は,エウカリオットゲノムにオルガネルの祖先を経由して遺伝子が入ったことを示唆し,エピソード的な遺伝子の流入を予測する.
研究 の 目的:
- エンドシンビオシスに関連したエピソード的遺伝子転送と,真核生物における連続的な横向的遺伝子転送を区別する.
- 核核生物の遺伝子ファミリーの進化史を,核核生物の同型生物と分析する.
- ユーカリ生物のゲノム進化に 遺伝子の移転が及ぼす長期的な影響を理解する.
主な方法:
- ユカリオット遺伝子の群集分析
- プロカリオット同種を持つ真核遺伝子の遺伝子の分析.
- 比較ゲノミクスと遺伝子分布分析
主要な成果:
- 細菌から真核生物への遺伝子の移転は,クロロプラストとミトコンドリアの起源と一致し,エピソード的です.
- ユカリオットの遺伝は主に垂直であり,遺伝子の喪失は稀な分布を説明する.
- 連続した横向遺伝子の移転は,長期の真核生物のゲノム進化において,限られた役割を果たしている.
結論:
- ユカリオットにおける細菌遺伝子の獲得の主なメカニズムは,エンドシンビオティックな出来事におけるエピソード的移転である.
- 縦継承と差異性遺伝子の喪失は,真核生物のゲノム内容の主な要因である.
- 連続した横向的な遺伝子転送は,長期の真核生物のゲノム進化を有意に形作らない.
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