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配偶者選択に関与する定量的な羽毛の特徴の保存された遺伝的基礎

Nicholas I Mundy¹, Nichola S Badcock, Tom Hart

¹Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK. nim21@cam.ac.uk

Science (New York, N.Y.)

|March 20, 2004

まとめ

メラニズム,または黒い羽毛は,より小さな雪と北極スカウのメラノコルチン-1受容体 (MC1R) 遺伝子の変異により独立して進化した. 変異性MC1R遺伝子の複製の数は,これらの鳥種のメラニズムの程度と相関しています.

科学分野:

進化遺伝学の進化遺伝学について
動物の色付け動物の色付け
分子進化は分子進化である.

背景:

異なる系統における類似した現象型の収束進化は,共通の遺伝的基盤についての疑問を提起する.
小雪や北極スカワなどの鳥のメラニク色羽毛ポリモルフィズムは,独立した現象型進化の古典的な例です.

研究の目的:

共有された遺伝的メカニズム,特にメラノコルチン-1受容体 (MC1R) 遺伝子の変異が,小雪や北極スクワのメラニズムの独立した進化に責任があるかどうかを調査する.

主な方法:

羽毛の色の変化とメラノコルチン-1受容体 (MC1R) 遺伝子との関連を,小雪と北極スクワーの比較で調べました.
メラニズム度数と両種における変異性MC1Rアレルの数との相関を定量化した.
メラニズムの進化史を追跡するために,変異性MC1Rアレルの系統遺伝的再構築を行った.

主要な成果:

メラニズムは,小雪と北極スカワーの両方とも,MC1R遺伝子の変異と完全に関連しています.
メラニズムの程度は,両種の個体に存在する変異MC1Rアレルの数と直接相関しています.
系統遺伝学的分析は,メラニズムがプレイストセーン時代にとスクワの両方において出現した派生特質であることを示しています.

結論:

MC1R遺伝子を含む共通の遺伝的メカニズムは,遺伝学的に異なる鳥種のメラニズムの独立した進化において重要な役割を果たしています.
MC1R遺伝子のコピー番号の変動は,メラニズム程度を決定する重要な要因であり,収束分子進化を例示しています.
これらの種のメラニズムの進化史は,比較的最近の起源と,異なる系統で独立した出現を示しています.

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