FACS analysis of fetal liver cells mosaic for the expression of GPI. A Piga^flox male mouse was crossed with hCMV-Cre female, and liver cells were prepared from day 14 embryos. (A) Liver cells from morphologically normal embryos. (B) Liver cells from morphologically abnormal female embryos. Fetal liver cells were stained for TER119 and HSA. Numbers in upper quadrants show percentages of HSA⁺ and HSA⁻TER⁺ cells.