遺伝子効果のプレオトロピックスケーリングと"複雑性のコスト"
Günter P Wagner1, Jane P Kenney-Hunt, Mihaela Pavlicev
1Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut 06520-8106, USA. gunter.wagner@yale.edu
Nature
|March 28, 2008
まとめ
進化的適応は,変異が複数の特徴に影響するプレオトロピーによる複雑な特性の課題に直面しています. この研究では,ほとんどの突然変異がいくつかの特徴に影響を及ぼすことが判明し,進化は"複雑性のコスト"を負わないことを示唆しています.
科学分野:
- 進化生物学の進化生物学について
- 遺伝学 遺伝学とは
- 発達生物学 発達生物学とは
背景:
- ダーウィンの進化論は,変異と選択による適応を説明する.
- 眼や飛行器のような複雑な特徴には,多数の協調した特徴が含まれています.
- 変異が複数の表型特性に影響するプレオトロピーは,複雑な特性の進化を理解する上で課題を提起する.
研究 の 目的:
- 進化的適応に対するプレオトロピーの影響を調査する.
- プレオトロピーは進化に"複雑性のコスト"を課すかどうかを判断する.
- 変異によって影響を受ける特性の数と,その影響の大きさとの関係を分析する.
主な方法:
- 定量的な特徴の位置 (QTLs) を用いてマウスのプレオトロピーを研究し,骨格の特徴に影響を与えた.
- 各QTLの影響を受ける特徴の数を分析した.
- QTL置換によって影響を受ける特性の数と,個々の特性に及ぼす影響の大きさを相関させた.
主要な成果:
- 特定されたQTLのほとんどは,骨格の特徴の小さなサブセットに影響を与えた.
- 特徴のQTL置換の効果の大きさは,そのQTLの影響を受ける特徴の総数とともに増加した.
- プレオトロピーは複雑な特徴の進化を妨げないという証拠がある.
結論:
- 高等な生物における複雑な特徴の進化は",複雑性のコスト"によって著しく妨げられない.
- 観察されたプレオトロピーのパターンは,ほとんどの変異がわずかな特徴に影響を及ぼし,進化の進歩を容易にします.
- 変異効果は,プレオトロピーの増加とともに必ずしも減少することはなく,強固な進化的適応を支えている.
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