古代のタンパク質は,ダーウィンの南米の類の進化史を解明する
Frido Welker1, Matthew J Collins2, Jessica A Thomas2
11] BioArCh, University of York, York YO10 5DD, UK [2] Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany.
Nature
|March 25, 2015
まとめ
現在,トキソドンやマクラウケニアのような南米原産の類は,系統遺伝学的にペリスソダクティラ (馬,サイ) と並んでいる. プロテオミクスは,DNA分析の限界を克服して,それらの進化的関係を成功裏に解決しました.
科学分野:
- パレオゲノミクスとは
- 分子体系論は,分子体系論である.
- 哺乳類の進化について
背景:
- 南米の原産の類は,絶滅した胎盤哺乳類の進化的に神秘的なグループです.
- モルフォロジーと古代DNAを用いた以前の系統遺伝学的分析は,それらの進化的起源に関して不確実な結果をもたらしました.
- 哺乳類のスーパーオーダー (Afrotheria vs. Laurasiatheria) の内の位置と,古来の胎盤 ("コンディラライト") との関係については,議論が続いている.
研究 の 目的:
- プロテオミクデータを用いて南米の原産の類の系統的位置を解明する.
- 哺乳類の樹内のトキソドン (Notoungulata) とマクラウケニア (Litopterna) の進化的関係を調査する.
- 古代のタンパク質配列の有用性を評価し,深い進化の歴史を再構築する.
主な方法:
- トキソドンとマクラウケニアの化石骨サンプルから採取した1型コラーゲンのα1およびα2鎖のプロテオミック分析.
- 高シーケンスカバー (約. 90%) のコラーゲン鎖が得られた.
- 化石タンパク質の配列を哺乳類のゲノムおよびプロテオミクデータと整合することによって,系統樹の構築.
主要な成果:
- トキソドンとマクラウケニアは,モノフィレティック群を形成する.
- このグループは,冠のペリスソダクティラ (馬,タピール,サイ) の姉妹分類として識別されています.
- この発見は,これらの類をAfrotheriaに配置する最近の仮説に異議を唱える.
結論:
- プロテオミクスは,絶滅した哺乳類の系統再建のための強力な方法を提供し,古代のDNA分解の限界を克服します.
- トキソドンやマクラウケニアを含む南米の原産の類は,古代の胎盤動物から発生し,ペリスソダクティラと密接に関連しています.
- この研究は,哺乳類の超正規関係と南米の動物界の進化史の理解を修正するのに寄与しています.
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