Fig 1: Spatiotemporal dynamics of yolk sac progenitor subsets endowed with progressive commitment to erythroid lineages(A) Yolk sac E10.5 CD41+ Kit+ cells can be subdivided in a tSNE representation (upper panel) into 4 populations A, B, C, and D (dashed lines). (Lower panel) Overlay of previous phenotypic definitions of EMPs (pink) on the t-SNE space (gray).(B) t-SNE representation of the fluorophore intensity of AA4.1, CD45, CD71, Kit, CD34, CD16/32, CD61, and CD41 in the four subsets. Please also see Figure S1B.(C) Representative contour plots of Kit and CD41 expression among lineage negative cells, of AA4.1 and CD34 among Kit+ CD41+ progenitor cells and of CD16/32 and CD45 among AA4.1neg CD34neg cells from E8 to E11.5 in the yolk sac (upper panel), blood (middle panel) and fetal liver (bottom panel). At least two independent litters analyzed per time point, except for E8 and E9. Number of analyzed embryos per time point indicated in (D).(D) Quantification of the number of cells per yolk sac in each population from E8.5 to E11.5. n = 3 at E8 (6–8 somite pairs [sp]), 11 at E8.75 (16–28 sp); 3 at E9 (20–21 sp); 7 at E9.5 (27–29 sp); 17 at E10.5 (34–38 sp); and 5 at E11.75 (51–53 sp). Bars represent mean± SEM.(E) Colony forming units (CFU-C) assays of sorted single cells in liquid culture analyzed 12 days after. Cloning efficiency (left) and frequency of colony types (E-Mk, erythroid and/or Mk; Myeloid and Mix colonies) (right); mean ± SEM. Two or four technical replicates of one pooled litter. Please also see Figure S1.