Short-term hematopoietic reconstitution by Erg^+/Mld2 bone marrow is not sustained. (A) Reconstitution of peripheral blood of lethally irradiated recipients by 1 × 10⁶GFP⁺Erg^+/+ or GFP⁺Erg^+/mld2 unfractionated bone marrow cells. GFP⁺ donor contribution is shown; each point is the mean of 4 recipients with 3 independent donors included. *P < .05, **P < .001, ***P ≤ .0001: intragenotype comparison of reconstitution at 4 and 20 weeks after transplantation. (B) Competitive transplantation of GFP⁺Erg^+/Mld2 or GFP⁺Erg^+/+ unfractionated bone marrow cells mixed with competitor Erg^+/+ bone marrow into lethally irradiated recipients. Peripheral blood reconstitution of mature lineages assessed at 4 weeks and 20 weeks after transplantation is shown for 1:1 ratio of GFP⁺Erg^+/+ to Erg^+/+ and 1:1 and 10:1 ratios of GFP⁺Erg^+/Mld2 to Erg^+/+ bone marrow cells. The mean ± SD of GFP⁺ donor contribution is shown from 3 independent experiments with 4 recipients per transplant. *P < .01, GFP⁺Erg^+/Mld2 1:1 competitive donor ratio compared 1:1 GFP⁺Erg^+/+:Erg^+/+ ratio transplant. **P < .01, GFP⁺Erg^+/Mld2 10:1 competitive donor ratio compared with 1:1 GFP⁺Erg^+/+:Erg^+/+ ratio transplant.