突变规则与生物系统的稀疏性和模块性演化
Mutation Rules and the Evolution of Sparseness and Modularity in Biological Systems
摘要：
生物系统在组织的许多层次上表现出两个结构特征：稀疏性，其中组件之间只有一小部分可能的相互作用实际发生;模块性-系统几乎可分解为具有不同功能的模块。最近的研究表明，模块化可以在各种情况下发展，包括目标随时间变化，从而共享相同的子目标（模块化变化的目标），或者当连接成本很高时。在这里，我们研究了模块化和稀疏性的起源，重点是突变过程的本质，而不是连接成本或目标的变化。我们使用不同的突变规则的进化模拟。我们发现，常用的求和规则突变，其中的相互作用是通过添加随机数突变，不导致模块化或稀疏，除非在特殊情况下。相比之下，乘积规则突变通过乘以随机数来改变相互作用--这是一个更好的生物突变效应模型--自然导致稀疏。当进化的目标是模块化的，即特定的输入组影响特定的输出组时，乘积规则的突变也会导致模块化结构，而求和规则的突变则不会。乘积规则突变产生稀疏性和模块性，因为它们倾向于减少交互，并使小的交互项保持较小。
英文摘要：
Biological systems exhibit two structural features on many levels of organization: sparseness, in which only a small fraction of possible interactions between components actually occur; and modularity - the near decomposability of the system into modules with distinct functionality. Recent work suggests that modularity can evolve in a variety of circumstances, including goals that vary in time such that they share the same subgoals (modularly varying goals), or when connections are costly. Here, we studied the origin of modularity and sparseness focusing on the nature of the mutation process, rather than on connection cost or variations in the goal. We use simulations of evolution with different mutation rules. We found that commonly used sum-rule mutations, in which interactions are mutated by adding random numbers, do not lead to modularity or sparseness except for in special situations. In contrast, product-rule mutations in which interactions are mutated by multiplying by random numbers - a better model for the effects of biological mutations - led to sparseness naturally. When the goals of evolution are modular, in the sense that specific groups of inputs affect specific groups of outputs, product-rule mutations also lead to modular structure; sum-rule mutations do not. Product-rule mutations generate sparseness and modularity because they tend to reduce interactions, and to keep small interaction terms small.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
