The hem6 anemia is transplantable. Irradiated C57BL/6J-Igh^a Thy1^a Gpi1 ^a +/+ or hem6/hem6 animals that had received C57BL/6J-Igh^b Thy1^b Gpi1^b hem6/hem6 (n = 7; black lines) or +/+ (n = 8; gray lines) fetal liver cells, respectively, were serially monitored for RBC chimerism (dotted lines) by Gpi1 isozyme analysis and for blood parameters. The decrease (in the case of hem6 → +) or increase (in the case of + → hem6) in MCV (solid lines) closely follows engraftment by the donor cells. Error bars indicate plus or minus 1 SD.