Enrichment for myeloid and erythroid CFCs in the lacZ^high fraction of fetal livers fromSCL^lacZ/w mice. (A) Representative FACS profiles of forward scatter plotted against β galactosidase activity (measured as fluorescence) for FACS-Gal–labeled E12.5 fetal liver cells fromSCL^lacZ/w and SCL^w/w embryos. Sort windows and the percentage of cells in each window are shown for lacZ^low and lacZ^high fractions for each genotype. (B) Frequency of d2 CFU-E and d7 BFU-E and myeloid (GM) CFC in cultures of unsorted and sorted fetal liver fractions fromSCL^lacZ/w mice cultured in Epo (for d2 CFU-E) or IL-3/Epo (for d7 BFU-E and GM-CFC). Values represent the mean ± SD from replicate cultures of 10 fetal livers from 3 litters of embryos. The percentage of fetal liver cells, which were sorted into each fraction, is indicated.