Allogeneic BM engraftment QTL. The BM engraftment phenotype was assessed in [B10.BR × (BALB.K × B10.BR)F1] BC mice (n = 200) given sublethal TBI and AKR/J BM. Shown are (A) the percentage of mice with engraftment 6 and 8 weeks after transplantation and (B) the percentage of donor T cells in blood of mice that engrafted, as determined by FACS for Thy1 markers, and donor B cells and myeloid cells, as determined by RT-PCR for CD22- and Ncf2 specific SNP markers. (C) Interval mapping using R/qtl for BM engraftment considered as a continuous trait (percentage donor T-cell value; solid line) or binary trait (yes, n = 37, or no, n = 163; dotted line) plotted according to chromosome position. (D) Interval mapping of chromosome 16. The rectangular box indicates the 1 LOD confidence interval for the continuous trait and demarcates the new BM engraftment QTL termed Bmgr5. The vertical lines on the x-axis indicate positions of SNP markers used for genotyping. The horizontal dashed lines indicate significant (P < .05) and highly significant (P < .001) LOD threshold levels determined by permutation tests.