Genotype analyses of blood cells from wild-type, low TF, and chimeric mice. PCR was performed on whole blood. (A) PCR using primers for the mouse TF gene. (B) PCR using primers for the human TF gene. WT indicates wild-type mouse; LTF, low TF mouse; WT/LTF, wild-type bone marrow/low TF mouse; LTF/WT, low TF bone marrow/wild-type mouse. All mice used were individually tested.