Representative FACS profiles of colonies derived from single cells. Sca-1⁺c-kit⁺ cells were purified from fetal liver and were plated individually by micromanipulation into methylcellulose media containing IL-2, IL-7, IL-11, and SF. After 18 days of culture, colonies were identified in situ and picked individually. Cells from each colony were stained with PE-anti–B220 and FITC-anti–Thy-1 and analyzed by FACS Vantage using Cell Quest software. Upper left: A mixed NK colony with B lineage cells. Upper right: A mixed NK colony without B lineage cells. FACS profile of a typical pure NK, pre-B or myeloid colony is also shown for comparison.