デウテロストームの系統化は,モノフィレティックなコルダ類と新しい系統であるXenoturbellidaを明らかにする
Sarah J Bourlat1, Thorhildur Juliusdottir, Christopher J Lowe
1Department of Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK.
Nature
|October 20, 2006
まとめ
デウテロストームの原型が明確にされ,オルファクトール (ウロコルダ生,脊椎動物) とアンブラクラリア (ヘミコルダ生,皮動物) を支持する. ゼノトゥルベッラ (Xenoturbella) は,デュテロストームの進化的関係を解決する独特の属であるゼノトゥルベッリダ (Xenoturbellida) として識別されています.
科学分野:
- * 進化生物学と動物系統学.
- * 比較ゲノミクスと分子体系論.
背景:
- * デウテロストームには,脊椎動物や脊椎のない動物,ヘミコルド類,皮動物,クセノトゥルベラ類が含まれます.
- * 過去の研究では,ウロコルダトが脊椎動物に最も近い親類であると示唆され,従来の見解に異議を唱え,コルダトのパラフィリアを提案しました.
研究 の 目的:
- * すべての主要なデウテロストーム群の間の進化的関係を解明する.
- * デウテロストーム内のクセノトゥルベラの系統的位置を調査する.
- * コード類のモノフィリアまたはパラフィリアを明確にするために.
主な方法:
- * 多種多様なデウテロストーム属の35,000以上の同類アミノ酸からなる大規模なアラインメントの組み立て.
- *Xenoturbella.のミトコンドリアゲノムの配列決定.
- *核とミトコンドリアのデータを組み合わせた系統遺伝分析.
主要な成果:
- *オルファクター (ウロコルダ類と脊椎類) とアンブラクラリア (ヘミコルダ類と皮類) のモノフィリーが確認された.
- * 提案された頭帯類と皮類のグループ化を拒絶し,帯類の単一性を支持した.
- * Ambulacrariaの姉妹グループとしてXenoturbellaを配置し,Xenoturbellidaという新しい属として確立しました.
結論:
- *この研究は,既定のクラードを支持し,コルダト・パラフィリアの仮説を否定している.
- *Xenoturbellaは,独立した進化の系統を表し,既知のデウテロストーム族群の数を4に増やす.
- * デュテロストームの進化と起源を理解するための堅実な枠組みを提供します.
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