アルカイア時代における高温への並行的な適応
Bastien Boussau1, Samuel Blanquart, Anamaria Necsulea
1Laboratoire de Biométrie et Biologie Evolutive, CNRS, Université de Lyon, Université Lyon I, 43 Boulevard du 11 Novembre, 69622 Villeurbanne, France.
Nature
|November 28, 2008
まとめ
最後の普遍的な共通の祖先 (LUCA) は,おそらくメソフィルであり,バクテリアとアーカイア-ユーカリオタの祖先は,後に高温に収束的に適応した. 熱耐性は進化の過程でこれらの系統で減少した.
科学分野:
- 進化生物学の進化生物学について
- ゲノミクスゲノミクスとは
- バイオケミストリー バイオケミストリー
背景:
- 初期の生命の化石を解釈することは困難であり,祖先の生態学を研究するための代替方法が必要である.
- 既存のゲノムにおける遺伝的足跡は,祖先の生物の温度についての洞察を提供します.
- 以前の研究は,最後の普遍的な共通の祖先 (LUCA) の熱環境に関する矛盾する仮説を導き出した.
研究 の 目的:
- 分子データを用いて初期の生命の熱的進化を調査する.
- LUCAの温度と祖先の耐熱性に関する矛盾する発見を調和させるため.
- 生命の樹の初期の温度適応段階を再構築するために.
主な方法:
- リボソームRNA (rRNA) とタンパク質の両方の配列の分析.
- 分子進化の高度で現実的なモデルを適用する.
- ゲノムデータに基づく先祖の熱適応を再構築.
主要な成果:
- 証拠は,2つの異なる温度に関連する進化段階を裏付けている.
- 熱耐性は,メソフィルのLUCAから,熱好きの細菌と古生物-真核生物の祖先に増加した.
- その後,熱耐性が低下し,高温への適応が収束していることを示した.
結論:
- LUCAはおそらくメソフィリックであり,熱愛的ではなかった.
- バクテリアとアルカイア-ユーカリオタの祖先は,おそらく気候変動やゲノム移行により,高温に収束的に適応した.
- この研究は,初期の生命の熱的進化に関する統一された見解を提供します.
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