To investigate the organotypic specification of human endothelial cells during organogenesis, we unbiasedly sorted ECs (CD45-CD31+ cells) from 17 organs/tissues covering 28 time points ranging from CS9 to the early third trimester PCW24 for scRNA-seq analysis.

We collected ECs from the major organs at different fetal stages for scRNA-seq analysi to figure out the spatial-temporal dynamics of EC specification during human development. Based on a total of 118,500 ECs that passed stringent quality standards, we subdivided the ECs into 12 subtypes and identified 10 prominent co-regulated gene modules that underlies the organotypic specification of different EC subtypes.