魚の内熱性の進化:分子フィロゲニーにおける生理学的特徴のマッピング

B A Block¹, J R Finnerty, A F Stewart

¹Department of Organismal Biology and Anatomy, University of Chicago, IL 60637.

Science (New York, N.Y.)

|April 9, 1993

まとめ

内熱性,すなわち内部の熱を生成する能力は,スカンブリッド魚類で3回独立して進化した. この特性は,冷たい水域への拡張を容易にし,有酸素能力を向上させなかった.

科学分野:

進化生物学の進化生物学について
イクチオロジーイクチオロジー
分子系遺伝学分子系遺伝学

背景:

エンドサーミーは,環境よりも高い体温を維持する能力であり,多様な進化的起源を持つ複雑な特徴です.
マクレル,トナ,そしてビルフィッシュを含むスコムブロイドイ魚は,多様な熱中戦略を示し,その進化を研究するためのモデルグループとなっています.

研究の目的:

スコムブロイドイ亜序列の分子フィロゲニスを調査するために.
この魚群内の内熱体の進化史と独立した起源を決定する.
頭蓋骨内熱症の進化を駆動する選択的圧力を理解するために.

主な方法:

ミトコンドリアのサイトクロームb遺伝子の直接シーケンシングにより,分子フィロゲニーが構築されます.
エンドサーミック種の分布を系統樹にマッピングする.
エンドサーミーの進化を環境要因,特に水温と相関させる.

主要な成果:

スコムブロイドイの分子系統が確立されました.
証拠は,このサブオーダー内の頭蓋骨内熱 (脳と網膜の温暖化) の3つの独立した進化的起源を示唆しています.
これらの独立した起源は,より寒い水域環境の植民地化と一致しました.

結論:

魚の頭蓋骨内熱は,熱的ニッチ拡大のメカニズムとして進化し,より寒い生息地の利用を可能にしました.
このグループにおけるエンドサーミーの進化は,主にエアロビック能力の向上の必要性によって引き起こされたわけではない.
この研究は,環境的課題への対応として,エンドサーミーの適応的重要性を強調しています.

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