CD34⁻KSL cells were clonally sorted into 96-well plates and cultured in the presence of SCF and TPO with or without TIMP-3, as described in “Methods.” Once they divided to generate daughter cell pairs, cells were separated by micromanipulation and subjected to colony assays. Colony types were evaluated by morphological examination as described in “Methods.” The experiments were done in triplicate (96 colony pairs were evaluated in each experiment), and percentages of colony pairs are shown (mean ± SD). Colonies from nmEM progenitors are highlighted in bold.