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The Lambda Select cII Mutation Detection System
Published on: April 26, 2018
实验证据表明,BGL操作子中存在一种替代于定向突变的替代方法
1Department of Ecology and Evolutionary Biology, University of California, Irvine 92717.
Nature
|April 2, 1992
概括
导向突变假设受到埃舍里奇亚大肠杆菌发现的挑战. 沙利丰富驱动了bgl操作子突变,不是通过定向突变,而是通过非生长细胞的自发突变,然后是缓慢生长.
科学领域:
- 微生物学 微生物学
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
背景情况:
- 定向突变假设认为,有利突变的突变率会增加.
- 这挑战了基因突变率独立于选择性优势的基本原则.
- 埃舍里希亚大肠杆菌的bgl操作子内的突变已被引用为潜在的定向突变的例子.
研究的目的:
- 在沙利选择下调查大肠杆菌中bgl操作子突变积累背后的机制.
- 确定这些突变是否支持定向突变假设或其他解释.
- 阐明中间基因型在使用沙利的突变物出现中的作用.
主要方法:
- 在含有沙利的介质上培养大肠杆菌K12菌株 (chi342LD).
- 对bgl操作突变的分析,包括bglF的IS150切除和bflR的突变.
- 突变频率的比较,有和没有沙利暴露.
主要成果:
- 在沙利辛的生长过程中观察到bglF切除突变的显著积累 (大于1%).
- 使用沙利 (Sal+) 的双重突变在沙利选择下也增加了频率.
- 在没有沙利的情况下,没有观察到这些突变的可比增加.
- 观察到的突变并不是由沙利直接引起的,因为它不是致变的.
结论:
- 在沙利选择下bgl操作子突变的积累并不是指向突变的证据.
- 这些突变来自于非增长群体的自发突变.
- 在沙利中,中间基因型的缓慢生长允许随后的有利突变导致快速生长.
- 这些发现支持一种与选择和生长动态相结合的自发突变模型.
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