TATTOO-seq delineates spatial and cell type-specific regulatory programs during limb patterning

The coordinated differentiation of progenitor cells into specialized cell types and their spatial organization into distinct domains is central to embryogenesis. Here, we applied a new unbiased spatially resolved single-cell transcriptomics method to identify the genetic programs that underlie the emergence of specialized cell types during limb development and their integration in space. We uncovered combinations of transcription factors whose expression patterns are predominantly associated with cell type specification or spatial position, enabling the deconvolution of cell fate and position identity. We demonstrate that the embryonic limb undergoes a complex multi-scale re-organization upon perturbation of one of its spatial organizing centers, including the loss of specific cell populations, specific alterations in the molecular identities of other pre-existing cell states and changes in their relative spatial distribution. Altogether, our study shows how multi-dimensional single-cell and spatially resolved molecular atlases could reveal the interconnected genetic networks that regulate the intricacies of organogenesis and its reorganization upon genetic alterations. ### Competing Interest Statement The authors have declared no competing interest.