Proportions of Sca-1⁺Lin⁻ cells in the FL of 14.5-dpc W⁴¹/W⁴¹ and +/+ embryos. Distribution of viable (PI⁻) Sca-1⁺ cells with low forward and orthogonal light scattering properties gated as previously described36 and plotted here according to their expression of c-kit and a combination of lineage markers. Gates shown correspond to the levels of fluorescence shown by 99% of unstained control cells.