Evaluation of exogenous reconstitution of transplanted irradiated hosts by wildtype and G3 B6 mTerc^−/− bone marrow cells.

(A) Quantification of Y chromosome–positive cells in the BM of irradiated female hosts after primary, secondary, and tertiary transplants with wildtype and G3 mTerc^−/− B6 male BM cells. Quantification was performed by chromosome painting with a mouse whole-chromosome painting probe directly labeled with Cy3. A pool of BM cells from 4 different animals was used; the number of cells analyzed is represented above each bar. Grey bars indicate the expected exogenous reconstitution, taking into account the reduction in the percentage of Y⁺ cells inoculated in each sequential transplant. (B) Quantification of telomere fluorescence by Q-FISH in male nuclei of wildtype and G3 mTerc^−/− B6 BM cells used as inoculum for transplants and 5 months after transplantation of those cells into irradiated female recipients. The telomere fluorescence was analyzed in nuclei that were positive for the Y-chromosome painting probes in a second sequential hybridization. The number of nuclei analyzed is represented above each bar. Results are expressed as the mean ± SE. *P < .01 for inoculum versus primary transplant.