FACS sort gates for the isolation of stromal progenitors from the CD38⁻, HLADR⁻ fraction of fetal bone marrow cells. Four populations were sorted, based on their pattern of CDw90/Thy1 and CD34 expression. Note that there were relatively more CD34⁻, CDw/Thy-1⁺ cells compared to CD34⁺, CDw90/Thy-1 cells. The CD34⁺ and CD90⁺ cells are shown as large black dots; the CD34⁻ and CDw90⁻ cells were shown in the lower left quadrant.