Data from: The emotion system promotes diversity and evolvability

Studies on the relationship between the optimal phenotype and its environment have had limited focus on genotype-to-phenotype pathways and their evolutionary consequences. Here we study how multi-layered trait architecture and its associated constraints prescribe diversity. Using an idealized model of the emotion system in fish, we find that trait architecture yields genetic and phenotypic diversity even in absence of frequency-dependent selection or environmental variation. That is, for a given environment, phenotype frequency distributions are predictable while gene pools are not. The conservation of phenotypic traits among these genetically different populations is due to the multi-layered trait architecture, in which one adaptation at a higher architectural level can be achieved by several different adaptations at a lower level. Our results emphasize the role of convergent evolution and the organismal level of selection. While trait architecture makes individuals more constrained than what has been assumed in optimization theory, the resulting populations are genetically more diverse and adaptable. The emotion system in animals may thus have evolved by natural selection because it simultaneously enhances three important functions, the behavioural robustness of individuals, the evolvability of gene pools, and the rate of evolutionary innovation at several architectural levels.

现有关于最优表型与所处环境之间关联的研究，对基因型到表型的调控通路及其进化效应的关注相对不足。本研究旨在探究多层级性状架构及其相关约束如何塑造生物多样性。我们以鱼类情绪系统的理想化模型为研究对象，发现即便不存在频率依赖型选择或环境波动，性状架构仍可催生遗传与表型多样性。换言之，在固定环境中，表型频率分布具有可预测性，而基因库的组成却难以预判。遗传背景各异的种群间却能保留相似表型，这一现象源于多层级性状架构：在更高架构层级上的一种适应性特征，可通过低层级的多种不同适应性机制实现。本研究结果凸显了趋同演化与个体层级选择的关键作用。尽管性状架构会使个体受到的约束比优化理论中假设的更强，但由此产生的种群却拥有更高的遗传多样性与环境适应性。因此，动物的情绪系统或许正是通过自然选择演化而来，因为它同时具备三项重要功能：提升个体的行为鲁棒性、增强基因库的可演化性，以及提升多架构层级的演化创新速率。