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根付いた系統形成は,初期の細菌の進化を解決する
Gareth A Coleman1, Adrián A Davín2, Tara A Mahendrarajah3
1School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK.
まとめ
この研究は,細菌の遺伝子の家族進化をモデル化し,最後の細菌共通の祖先 (LBCA) が,おそらく自由に生きる二重膜の生物であったことを明らかにした. 垂直遺伝子の移転は,重要な水平遺伝子の移転 (HGT) にもかかわらず,支配的であり続けています.
科学分野:
- 微生物学
- 進化生物学
- バイオ情報学
背景:
- バクテリアの初期進化を理解するには 根付いたバクテリアの樹を確立することが重要です
- 根の正確な位置と水平遺伝子の移転 (HGT) の範囲は依然として議論されている.
- 最後の細菌共通の祖先 (LBCA) の特徴は十分に理解されていません.
研究 の 目的:
- バクテリアの樹の根元を 決定するために 11272の遺伝子ファミリーの 進化をモデルにしました
- バクテリアの進化における水平遺伝子転送 (HGT) の範囲を定量化する.
- 最後の細菌共通の祖先 (LBCA) の特徴を推測する.
主な方法:
- バクテリアの遺伝子ファミリー11272の遺伝子解析
- 遺伝子の家族進化をモデル化して 進化史を推論する.
- 比較ゲノミクスは 祖先の特性を再構築します
主要な成果:
- バクテリアの樹はテラバクテリアとグラシリキュート群の間に根付いている.
- LBCAは,自由に生きる,鞭状の,棒状の,二重膜の生物として特徴付けられています.
- クロロフレクソタの姉妹であるテラバクテリアの内部の枝である.
- 遺伝子ファミリーの92%がHGTの証拠を示していますが,遺伝子の伝播の66%は垂直です.
結論:
- 提案された根の位置を持つ根付いたバクテリアの樹は,バクテリアの進化を解釈するための有効な枠組みを提供します.
- LBCAは複合的な特徴を持ち 双重膜と鞭状の細胞も含まれていました
- 遺伝子の垂直移転は,広範囲にわたるHGTにもかかわらず,いくつかの研究によって以前から示唆されたより重要な役割を果たしています.
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