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脊椎動物における Hoxa11 調節の進化は,ペンタダクティル状態と関連している
Yacine Kherdjemil1,2, Robert L Lalonde3, Rushikesh Sheth1
1Genetics and Development Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Québec H2W 1R7, Canada.
Nature
|October 6, 2016
まとめ
手足の進化には,多ダクティルの足から五ダクティルの足への移行が伴う. 遺伝子調節,特にホクサ11とホクサ13の発現は,四足類のペンタダクチル状態の確立に不可欠でした.
科学分野:
- 進化的発達生物学
- 比較ゲノミクス
- 脊椎動物の古生物学
背景:
- 翼から四肢への移行は 地球上の生命を可能にする 進化の重要な出来事です
- 初期の四足類は,現存するほとんどの四足類の五足類と違って,多爪類の四足類を持っていた.
- ペンタダクティルの四肢への移行の根底にある遺伝的メカニズムはほとんど不明である.
研究 の 目的:
- ペンタダクティル四肢の発達における Hoxa11とHoxa13遺伝子の役割を調査する.
- 手足の進化過程で Hoxa11 と Hoxa13 の発現を制御する制御要素を特定する.
- 手足のパターンの進化的起源を理解する
主な方法:
- マウスモデルにおける遺伝子発現パターンの分析
- 遺伝子操作と増強剤活性アッセイを含む機能研究.
- テトラポッドと魚 (ゼブラ魚) の間の遺伝子調節の比較分析.
主要な成果:
- Hoxa11とHoxa13の相互排斥的な発現は,ペンタダクティルの四肢形成に不可欠である.
- HOXA13とHOXD13によって活性化され,Hoxa11の場所でのアンチセンセスの転写を駆動する増強剤が,この排除を媒介する.
- この調節性増強剤はゼブラフィッシュには存在せず 羽根から四肢への移行時に現れることを示唆している.
結論:
- ポリダクチルからペンタダクチルへの移行において,特定の強化剤の獲得を含むHoxa11の制御の進化は重要なステップでした.
- この規制の革新は,四足類の特徴的なペンタダクティル四肢構造の確立を容易にした.
- これらの遺伝的メカニズムの理解は,脊椎動物の形態学的多様性の進化の洞察を提供します.
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