Rebuttal: adaptive point mutation (Rosenberg and Hastings).
Rebuttal: adaptive point mutation (Rosenberg and Hastings).
复制标题
反驳：适应性点突变（Rosenberg 和 Hastings）。
DOI：
10.1128/jb.186.15.4845.2004
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发表时间：
2004
影响因子：
3.2
通讯作者：
Foster,PatriciaL
中科院分区：
文献类型：
--
作者：
Foster,PatriciaL
罗森博格和黑斯廷斯(4)犯了与罗斯和安德森(5)同样的逻辑谬误。他们首先指出有三种模型来解释适应性突变：定向突变、超突变和隐生长。然后他们反对定向突变和隐式生长，把超突变作为唯一的选择。但是，他们忽略了我在综述(2)中提出的另一种模型，这种模型既不涉及定向突变，也不涉及隐性生长。我的模型假设了一种所有细胞都能参与的潜在突变机制；但是，在少数细胞（超突变细胞）中，这一过程比大多数细胞更具诱变性，因为Pol IV高度表达，错配修复缺陷。大多数产生90%的Lac突变，超突变产生10%的Lac突变，但超突变产生所有的多重突变。在超突变体中只有少数Lac突变的结论部分是基于Lac细胞具有另外两种突变的频率高于预期。罗森博格和黑斯廷斯认为，这是因为一些细胞在超可变状态下花费的时间更长，因此有更多的突变。确实，在乳糖选择过程中，具有多重突变的细胞比例随着时间的推移而增加(3)。但是这种影响还不足以解释三重突变的频率。论点如下（凯恩斯，《人际交往》）。
Rosenberg and Hastings (4) commit the same logical fallacy as do Roth and Andersson (5). They first state that there are three models to explain adaptive mutation: directed mutation, hypermutation, and cryptic growth. Then they argue against directed mutation and cryptic growth, leaving hypermutation as the only alternative. But, they ignore the alternative model that I presented in my review (2), which involves neither directed mutation nor cryptic growth. My model postulates one underlying mutational mechanism in which all cells can engage; but, in a few cells (the hypermutators) the process is more mutagenic than in the majority because Pol IV is highly expressed and mismatch repair is deficient. The majority produces 90% and the hypermutators produce 10% of the Lac mutations, but hypermutators produce all of the multiple mutations.The conclusion that only a few Lac mutations arise in hypermutators is based, in part, on the higher than expected frequency of Lac cells with two other mutations. Rosenberg and Hastings argue that this is because some cells spend more time in the hypermutable state and thus have more mutations. It is true that the proportion of cells with multiple mutations increases with time during lactose selection (3). But this effect is not large enough to account for the frequency of triple mutants. The argument is as follows (J. Cairns, personal communication).