サメのミトコンドリアDNA進化の速度は,哺乳類と比較して遅い

A P Martin¹, G J Naylor, S R Palumbi

¹Department of Zoology, University of Hawaii, Honolulu 96822.

Nature

|May 14, 1992

まとめ

分子時計の速度は,脊椎動物種によって大きく異なります. サメのミトコンドリアDNAの進化は霊長類の7〜8倍遅いため,正確な分子年代測定をするために,分類別特別の校正が必要である.

科学分野:

進化生物学の進化生物学について
分子進化は分子進化である
ゲノミクスゲノミクスとは

背景:

ミトコンドリアDNA (mtDNA) の進化率は,主に霊長類で調整されています.
脊椎動物の間で恒常的な分子時計が存在すると広く考えられているが,検証されていない.
以前の仮定は,不正確な差異時間推定につながる可能性があります.

研究の目的:

脊椎動物における分子時計の定常性仮説を検証するために.
サメのミトコンドリアDNA配列の変異を調べるために.
サメや他の脊椎動物群の進化速度を比較する.

主な方法:

13種のサメのmtDNA配列の変異を分析した.
配列化されたサイトクロームbおよびサイトクローム酸化酵素I遺伝子.
パナマ領で隔離された種を含む霊長類と類のデータと比較した置換率.

主要な成果:

サメのmtDNAの置換率は,霊長類や類よりも7〜8倍遅い.
この速度の差は,核酸バイアス,選択,または遺伝子選択に起因するものではありません.
最近分裂したサメの種で確認された減速率.

結論:

分子時計は,すべての脊椎動物の分類において一定ではない.
他のグループに対して霊長類ベースの校正を使用することは不適切です.
タクソン特有の校正は,高解像度の分子進化の研究に不可欠です.

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