Analysis of retroviraly transduced Lin⁻fetal liver cells. The light scatter properties of the cells were measured (A), and the major population was identified and gated for further analysis (shown in box). This population was then analyzed for the presence of c-Kit on the cell surface ([B] shaded area, control cells; open area; cells labeled with anti–c-Kit antibodies). Note that FL-2 measures PE. The c-Kit⁺ cells were further analyzed for B12 fluorescence ([C] shaded area, control cells; open area, transduced cells). Note that FL-1 measures B12SPM. The experiment was repeated twice, and the representative data from one experiment are shown.