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The Lambda Select cII Mutation Detection System
Published on: April 26, 2018
bgl オペロンにおける指向型変異の代替品の実験的証拠
1Department of Ecology and Evolutionary Biology, University of California, Irvine 92717.
Nature
|April 2, 1992
まとめ
誘導変異仮説は,Escherichia coli.における発見によって異議を唱える. サリシン濃縮は,指向型変異によってではなく,成長しない細胞の自発的な変異によって,その後成長が遅くなるように,BGLオペロン変異を誘発する.
科学分野:
- 微生物学 微生物学とは
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
背景:
- 誘導変異仮説は,有利な変異によって変異率が増加すると仮定する.
- これは,突然変異率が選択的優位性から独立しているという基本的原則に異議を唱える.
- Escherichia coli の bgl オペロン内の変異は,指向変異の潜在的な例として引用されています.
研究 の 目的:
- サリシン選択によるEscherichia coliにおけるbglオペロン変異の蓄積の背後にあるメカニズムを調査する.
- これらの突然変異が誘導突然変異仮説または代替説明を支持するかどうかを判断する.
- サリシンを利用する突然変異体の出現における中間型遺伝子の役割を明らかにする.
主な方法:
- サリシンを含有する介質でEscherichia coli K12菌株 (chi342LD) の培養.
- bglオペロンの変異の分析,bglFからのIS150切除およびbflRの変異を含む.
- サリシン被曝と無被曝の突然変異の頻度の比較.
主要な成果:
- サリシンの成長中に観察されたbglF切除変異体の有意な蓄積 (1%以上).
- サリシン利用型 (Sal+) ダブルミュータントの発生頻度も,サリシン選択で増加した.
- これらの突然変異の比較可能な増加は,サリシンの欠如では観察されなかった.
- 観察された変異は,サリチンが突然変異を起こさないため,サリチンが直接引き起こしたものではない.
結論:
- サリシン選択によるbglオペロン変異の蓄積は,指向変異の証拠ではない.
- これらの変異は,成長しない集団における自発的な変異から生じる.
- サリシンで中間型遺伝子の成長が遅いため,その後の有利な突然変異が起こり,急速な成長につながります.
- 発見は,選択と成長のダイナミクスと組み合わせた自発的な突然変異のモデルを支持します.
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