ミトコンドリアのtRNAの補償的な進化は,体格の低い谷をナビゲートする
Margarita V Meer1, Alexey S Kondrashov, Yael Artzy-Randrup
1Bioinformatics and Genomics Programme, Centre for Genomic Regulation, C/Dr Aiguader 88, Barcelona Biomedical Research Park Building, 08003 Barcelona, Spain.
Nature
|February 26, 2010
まとめ
進化の系統は,補償的進化によってフィットネス・バレーを横切ることができる. これは,哺乳類のミトコンドリアのtRNAの希少で中間的な変異によって発生し,有害なアレルの同時固定が一般的であることを示唆しています.
科学分野:
- 進化生物学の進化生物学について
- 分子進化は分子進化である
- 遺伝学 遺伝学とは
背景:
- 進化生物学における重要な質問は,系統が低フィットネス状態を克服して,より高いフィットネスピークに到達できるかどうかです.
- フィットネスの風景は,有害な遺伝子型を象徴する渓谷とともに,進化の軌道を描いています.
研究 の 目的:
- 哺乳類のミトコンドリアのtRNA幹部領域におけるワトソン・クリックのスイッチの進化的動態を調査する.
- これらの進化的移行の間に中間状態に関連したフィットネスコストを定量化するために.
主な方法:
- 83種の哺乳類における補完的なtRNA部位におけるワトソン・クリック・ヌクレオチドペア置換 (AU/GC) の分析.
- ヒト集団におけるフィットネスバレーの深さの推定と中間アレル周波数 (GU,AC) の分析.
- ミトコンドリアのtRNAにおける置換相関の検討.
主要な成果:
- ワトソン・クリックのスイッチは,中性置換よりも (30〜40倍) かなり遅い.
- 中間ゲノムゲノムとACゲノムゲノムアレルは,ヒト集団では低周波で存在しています.
- これらのスイッチには,約10^-3から10^-2の深さのフィットネスバレーが推定されており,ACの中間はより有害である.
結論:
- 哺乳類のミトコンドリアのtRNAの補償進化は,希少で固定不能な中間変種を経由して進行する.
- このプロセスの普遍性は,個別に有害なアレルの同時固定が一般的な分子進化のメカニズムであることを示唆しています.
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