The Wnt signal transduction pathway has essential roles in the formation of the primary body axis during development, cellular differentiation and tissue homeostasis. This animal-specific pathway has been studied extensively in contexts ranging from developmental biology to medicine for more than 40 years. Despite its physiological importance, an understanding of the evolutionary origin and primary function of Wnt signalling has begun to emerge only recently. Recent studies on very basal metazoan species have shown high levels of conservation of components of both canonical and non-canonical Wnt signalling pathways. Furthermore, some pathway proteins have been described also in non-animal species, suggesting that recruitment and functional adaptation of these factors has occurred in metazoans. In this Review, we summarize the current state of research regarding the evolutionary origin of Wnt signalling, its ancestral function and the characteristics of the primal Wnt ligand, with emphasis on the importance of genomic studies in various pre-metazoan and basal metazoan species.

Wnt 信号转导通路在发育、细胞分化和组织稳态过程中主要身体轴的形成中发挥重要作用。从发育生物学到医学，这种动物特异性途径已被广泛研究了 40 多年。尽管其生理学重要性，但对 Wnt 信号的进化起源和主要功能的理解直到最近才开始出现。最近对非常基础的后生动物物种的研究表明，规范和非规范 Wnt 信号通路的组成部分具有高度保守性。此外，一些途径蛋白也在非动物物种中得到描述，表明这些因子的募集和功能适应已经发生在后生动物中。在这篇综述中，我们总结了有关 Wnt 信号的进化起源、其祖先功能和原始 Wnt 配体特征的研究现状，重点强调了基因组研究在各种前后生动物和基础后生动物物种中的重要性。