広範な系統学的サンプリングにより,動物の生命の樹の解像度が向上します
Casey W Dunn1, Andreas Hejnol, David Q Matus
1Kewalo Marine Laboratory, PBRC, University of Hawaii, 41 Ahui Street, Honolulu, Hawaii 96813, USA. casey_dunn@brown.edu
Nature
|March 7, 2008
まとめ
新しい分子データは,動物の深い進化的関係を解明し,エクディゾゾアやロフォトロコゾアのような主要なクラードを確認しています. この研究は,ベルベットワームの配置を明確にし,最も初期の動物としてのクテノフォアを含む新しい仮説を支持します.
科学分野:
- * 動物の進化生物学
- * 分子系遺伝学
- * ゲノミクスについて
背景:
- * 伝統的な動物の進化樹は分子データによって挑戦され,EcdysozoaやLophotrochozoaのような新しいクラードが提案されています.
- * 深い動物の関係を解明することは,キャラクターの進化を理解するために不可欠ですが,限られたデータと深いノードへの低いサポートによってしばしば妨げられます.
- * 系統遺伝学的なアプローチは有望ですが,多様な動物系統にわたるより広範なデータカバーが必要です.
研究 の 目的:
- * 深い進化的関係の解明を改善するために,幅広い動物群から新しい発現配列タグ (EST) データを生成する.
- *モルルシカの単一群と節足類の姉妹群を含む動物系統に関する既存の仮説をテストし,精錬する.
- * 螺旋分裂の進化的起源とクテノフォアの系統遺伝的位置を調査する.
主な方法:
- *29種の動物から21の系統にわたる39.9MBの表現された配列タグ (EST) の配列化.
- *新しいESTデータと既存の配列データを統合して,包括的な系統遺伝分析を行う.
- * 系統遺伝学的な方法を適用して,大規模で統合されたデータセットを分析する.
主要な成果:
- *Protostomia,Ecdysozoa,およびLophotrochozoaなどの主要なクラードの強化.
- *長年にわたる論争の明確な解決,特に軟毛虫をアルトポッドの姉妹集団として位置付け,タルディグラードではなく.
- * 軟体類の単一性および新しい仮説に対する強力な分子支持,軟体類を姉妹としてアネリド-ネメルテアン-ブラキオポッドクラード,そして最も初期の分岐動物としてクテノフォアを含む.
結論:
- *この研究は,主要な動物群の有力な分子証拠を提供し,重要な系統遺伝的不確実性を解消しています.
- *クテノフォアの基礎位置を含む,動物の関係に関する新しい仮説は,強く支持されています.
- * 系統遺伝学的なデータは,初期の動物進化の理解を大幅に進めており,残っている反抗的な系統はほとんどありません.
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