When blood development meets single-cell transcriptomics

Blood cells arise during embryonic development by three temporally distinct waves. Belonging to the third wave, hematopoietic stem cells (HSCs) are generated from hemogenic endothelium via endothelial-to-hematopoietic transition in mid-gestational embryos. Recently, studies combined with single-cell transcriptomics have provided massive new insights into the molecular evolutions and the underlying mechanisms of distinct waves of hematopoietic specification. In this review, we discuss the current single-cell profiling techniques, the most recent novel findings involved in the generation of distinct waves of blood cells, especially the HSCs, using single-cell transcriptional profiling combined with functional evaluations, and the perspectives to use the accumulating huge single-cell transcriptional data sets to study developmental hematopoiesis.