Transfer of the erythroid phenotype of p45 NF-E2 knockout mice after fetal liver transplantation from mutant mice into lethally irradiated wild-type recipients. (A) Comparison of spleen size in representative recipients transplanted with cells derived from control (left two) or p45 NF-E2^−/− (right two) fetal livers. (B) Histograms of RBC volume (top panel; 0 to 180 fL on the abscissa) and hemoglobin (Hgb) concentration (bottom panel; 0 to 45 g/dL on the abscissa) in 2 recipients transplanted with fetal liver cells from p45 NF-E2^+/− (left) or p45 NF-E2^−/− (right) mice; the results are representative of independent analysis of 5 adult recipients each of fetal liver cells from control and knockout mice. Vertical bars delineate approximate normal boundaries for common strains of laboratory mice.