B6 (Ly5.1) mice are more sensitive to irradiation than B6-Ly5.2. (A) Survival comparison in the Ly5.1 mice after different irradiation doses. Ly5.1 are susceptible to irradiation doses ≥ 1100 cGy. All animals received a BMT the same day of irradiation (B). Survival comparison between congenic B6-Ly5.2 mice and Ly5.1 mice post irradiation doses of 1100 cGy, 1000 cGy or less. Ly5.2 mice are more radioresistant than Ly5.1 mice at TBI doses of 1100 cGy. *p < 0.001, **p = 0.068.