Single-nucleus profiling decoding the subcortical visual pathway evolution of vertebrates.

During the evolution of vertebrates, significant transformations have occurred in the visual transmission and processing pathways. However, our understanding of the differences between two primary visual pathways in vertebrates and their evolutionary changes remains limited. The emerging technologies and comparative analysis have provided us with a more comprehensive way to decipher this process. Here, we applied single-nucleus RNA sequencing (snRNA-seq) onto the avian optic tectum, one of the key visual subcortical hubs in birds, to construct its cellular landscape. By integrating these data with mammalian snRNA-seq datasets, we revealed differences in the density of two types of thalamic-projecting excitatory neurons within the retinotectal pathway of birds and mammals. Additionally, a series of shared molecules were identified between two types of dominant visual pathways in vertebrates. Overall, this work provides a novel focus on the evolution of visual pathways and establishes a framework for their comparative analysis.