Fitness, flux and phantoms in temporally variable environments.
Fitness, flux and phantoms in temporally variable environments.
复制标题
临时变化环境中的适应度、通量和幻象。
DOI：
10.1093/genetics/136.4.1481
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发表时间：
1994
期刊：
影响因子：
3.3
通讯作者：
Dean,AM
中科院分区：
文献类型：
--
作者：
Dean,AM
在时间可变的环境中的选择的进化问题是通过调查的代谢模型描述的方法从一个简单的线性途径的不饱和酶催化可逆的单分子反应产生的通量的稳定状态。分析证实了以前的说法，步骤没有影响稳态通量可能会影响瞬态行为，在稳态免疫自然选择的酶可能会成为选择时，健身是一个功能的个人瞬态代谢事件。事实上，计算表明，大肠杆菌的β-半乳糖苷酶，其对稳态乳糖通量的影响可以忽略不计，控制着接近稳态。然而，在6秒后，乳糖通量在稳定状态的0.1%内，因此必须调用不断变化的环境来持续地将β-半乳糖苷酶暴露于选择。代谢模型经历多个瞬态事件的分析表明，健身差异保持不受影响，如果酶活性保持不变，并成为最小化，如果酶活性不同的环境。在获得适当的数据之前，认为代谢行为偏离稳态必然会使大部分等位酶暴露于自然选择的说法应该受到极大的怀疑。
The evolutionary problem of selection in temporally variable environments is addressed by investigating a metabolic model describing the approach to steady state of a flux emanating from a simple linear pathway of unsaturated enzymes catalyzing reversible monomolecular reactions. Analysis confirms previous claims that steps having no influence on the steady state flux may influence transient behavior, and that enzymes immune to natural selection at steady state may become subject to selection when fitness is a function of individual transient metabolic events. Indeed, calculations show that the beta-galactosidase of Escherichia coli, which exerts a negligible effect on the steady state lactose flux, controls the approach to steady state. However, after 6 sec the lactose flux is within 0.1% of steady state, and so an ever changing environment must be invoked to continually expose beta-galactosidase to selection. Analysis of the metabolic model undergoing multiple transient events reveals that fitness differences remain unaffected if enzyme activities remain constant and become minimized if enzyme activities differ among environments. Until suitable data become available, claims that metabolic behavior away from steady state necessarily exposes a far greater proportion of allozymes to natural selection should be treated with great skepticism.