Transplantation of Polg^A marrow into Polg⁺ recipients recapitulates megaloblastic features of Polg^A mice. Cells from the bone marrow and spleen of 10-month-old transplant recipient mice were prepared and analyzed as described in Figure 2. The individual graphs presented are representative of 3 independent experiments, in which a total of 3 Polg^A and 5 Polg⁺ mice were analyzed. The percentages shown with each region represent the mean frequency of that population, as a percentage of all singlet events, across all 3 experiments. *P < .05, **P < .01, as assessed by Student t test, for regions with statistically significant differences in frequency between genotypes. (A) All events remaining after exclusion of debris and nonsinglet events (80%-90% of all events; data not shown), were analyzed on the basis of expression of CD71 and Ter119. The frequency of Ter119⁺ cells, as a percentage of all singlet events, is presented. (B) The regions indicated in panel A were further analyzed on the basis of cell size relative to expression of CD71. (C) Whole bone-marrow cell suspensions from 10-month-old recipients of Polg⁺ (top panels) and Polg^A (bottom panels) marrow prepared as in Figure 2 demonstrate the presence of abnormally hemoglobinized orthochromatic normoblasts (arrows) in Polg^A marrow only and normal polychromatic normoblasts (arrowheads) in both Polg⁺ and Polg^A marrow. All images were acquired at identical magnification; bar represents 10 microns.