Emergence of homeostasis and "noise imprinting" in an evolution model.
Emergence of homeostasis and "noise imprinting" in an evolution model.
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DOI：
10.1073/pnas.96.19.10746
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发表时间：
1999-09
影响因子：
11.1
通讯作者：
M. Stern
中科院分区：
文献类型：
--
作者：
M. Stern
动态平衡，即创造一个稳定的内部环境，在生物进化中无处不在，尽管从一个区域排除噪声信息会带来熵成本。稳定的优势似乎不言而喻，但替代方案并不那么明显。这个问题是通过对一个简单的进化模型进行的数值实验来研究的：一个布尔型网络“生物体”种群被选为在受到噪声的情况下执行曲线拟合任务。在进化过程中，噪声敏感度随着适应度的增加而增加。噪音排斥是自发进化的，但只有在噪音足够不可预测的情况下。局限于一种或几种刻板印象的噪音会导致对称性破坏，从而阻止噪音排除。取而代之的是，生物体以极小的代价将噪音融入到它们的功能中，最终达到了健康水平，并完全依赖于噪音。这种“噪音印记”表明，在解释自然界中出现的明显适应时要谨慎。如果噪声在世代间是完全随机的，则排除噪声的进化是可靠且不可逆的，但如果噪声是经过几代相关的，则噪声相关性状的非适应性选择可以逆转排除噪声，从而对种群适应度造成灾难性影响。进入选择过程的噪声而不是生物体具有不同的影响：自适应进化在临界噪声幅度以上被完全取消，其方式类似于热力学相变。对噪声的进化适应涉及创建一个从噪声信息中筛选出来但越来越容易受到其影响的子系统。类似的考虑可能也适用于人类文化进化中的信息传导。
Homeostasis, the creation of a stabilized internal milieu, is ubiquitous in biological evolution, despite the entropic cost of excluding noise information from a region. The advantages of stability seem self evident, but the alternatives are not so clear. This issue was studied by means of numerical experiments on a simple evolution model: a population of Boolean network "organisms" selected for performance of a curve-fitting task while subjected to noise. During evolution, noise sensitivity increased with fitness. Noise exclusion evolved spontaneously, but only if the noise was sufficiently unpredictable. Noise that was limited to one or a few stereotyped patterns caused symmetry breaking that prevented noise exclusion. Instead, the organisms incorporated the noise into their function at little cost in ultimate fitness and became totally noise dependent. This "noise imprinting" suggests caution when interpreting apparent adaptations seen in nature. If the noise was totally random from generation to generation, noise exclusion evolved reliably and irreversibly, but if the noise was correlated over several generations, maladaptive selection of noise-dependent traits could reverse noise exclusion, with catastrophic effect on population fitness. Noise entering the selection process rather than the organism had a different effect: adaptive evolution was totally abolished above a critical noise amplitude, in a manner resembling a thermodynamic phase transition. Evolutionary adaptation to noise involves the creation of a subsystem screened from noise information but increasingly vulnerable to its effects. Similar considerations may apply to information channeling in human cultural evolution.