Abstract：
Biological genotypes do not code directly for phenotypes; developmental physiology is the control layer that separates genomes from capacities ascertained by selection. A key aspect is cellular competency, since cells are not passive materials but descendants of unicellular organisms with complex context-sensitive behavioral capabilities. To probe the effects of different degrees of cellular competency on evolutionary dynamics, we used an evolutionary simulation in the context of minimal artificial embryogeny. Virtual embryos consisted of a single axis of positional information values provided by cells\' \'structural genes\', operated upon by an evolutionary cycle in which embryos\' fitness was proportional to monotonicity of the axial gradient. Evolutionary dynamics were evaluated in two modes: hardwired development (genotype directly encodes phenotype), and a more realistic mode in which cells interact prior to evaluation by the fitness function (\"regulative\" development). We find that even minimal ability of cells with to improve their position in the embryo results in better performance of the evolutionary search. Crucially, we observed that increasing the behavioral competency masks the raw fitness encoded by structural genes, with selection favoring improvements to its developmental problem-solving capacities over improvements to its structural genome. This suggests the existence of a powerful ratchet mechanism: evolution progressively becomes locked in to improvements in the intelligence of its agential substrate, with reduced pressure on the structural genome. This kind of feedback loop in which evolution increasingly puts more effort into the developmental software than perfecting the hardware explains the very puzzling divergence of genome from anatomy in species like planaria. In addition, it identifies a possible driver for scaling intelligence over evolutionary time, and suggests strategies for engineering novel systems in silico and in bioengineering.
摘要：
生物基因型不直接编码表型；发育生理学是将基因组与通过选择确定的能力分开的控制层。一个关键方面是细胞能力，因为细胞不是被动材料，而是具有复杂的上下文敏感行为能力的单细胞生物的后代。为了探讨不同程度的细胞能力对进化动力学的影响，我们在最小人工胚胎发生的背景下使用了进化模拟。虚拟胚胎由细胞\'\'结构基因\'提供的位置信息值的单个轴组成，通过进化周期进行操作，其中胚胎的适应性与轴向梯度的单调性成正比。在两种模式下评估进化动力学：硬连线发育（基因型直接编码表型），以及一种更现实的模式，在这种模式下，细胞在通过适应度函数进行评估之前相互作用(“调节”发展)。我们发现，即使细胞提高其在胚胎中的位置的能力很小，也会导致进化搜索的性能更好。至关重要的是，我们观察到，行为能力的增加掩盖了结构基因编码的原始适应度，选择有利于改善其发展问题解决能力，而不是改善其结构基因组。这表明存在强大的棘轮机制：进化逐渐被锁定在其代理基质的智能改进中，对结构基因组的压力降低。这种反馈循环中，进化越来越多地投入到开发软件中，而不是完善硬件中，这解释了像涡虫这样的物种基因组与解剖学的非常令人费解的分歧。此外,它确定了在进化时间内扩展智能的可能驱动因素，并提出了在计算机和生物工程中设计新系统的策略。
