大量の酵母集団におけるハプロイドの進化上の利点
Clifford Zeyl1, Thomas Vanderford, Michele Carter
1Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA. zeylcw@wfu.edu
Science (New York, N.Y.)
|January 25, 2003
まとめ
2組の遺伝子を有する二重性 (diploidy) は,常に適応を加速するものではありません. イーストの集団では,二倍性菌は大きな群の適応を遅らせたが,小さな群には影響がなかった,特に有益な変異が部分的に後退している場合.
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
背景:
- 二重性 (二つの遺伝子コピー) は植物や動物に共通しているが,その進化上の優位性は不明である.
- ディプロイディは有益な変異率を増加させる可能性があるが,モデルは常に適応を加速させるわけではないことを示唆している.
研究 の 目的:
- ディプロイドとハプロイドの集団における適応率に関するモデル予測をテストする.
- 実験的進化を用いて,進化的適応に対するプロイディの影響を調査する.
主な方法:
- 適応率を実験的に比較するために無性酵母集団を使用した.
- 集団の大きさを操作し,プロイディ (diploidy vs. haploidy) の影響を評価した.
- 有益な突然変異の優位性を特徴づけた.
主要な成果:
- 適応性突然変異は,平均して部分的に後退していることが判明しました.
- ディプロイドは,大きな集団における適応を著しく遅らせました.
- ディプロイディは,小集団における適応率に有意な影響を及ぼさなかった.
結論:
- 実験結果は,二重症が適応を妨げることを予測する理論的モデルと一致しています.
- 適応に対する二重体性の影響は,集団の大きさに依存しています.
- 変異の優位性は,進化の軌道のプロイディの影響に影響を与える.
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