Engraftment assay after intravenous infusion of 1:1 mixtures of 2.5 × 10⁵RS-MSCs and 2.5 × 10⁵SR-MSCs from donors with different A/A and G/G alleles. (A) Schematic of brain regions assayed. (B) Example of competitive SNP assay. Genomic DNA isolated brain section D of mouse no. 3 was assayed. (C) Immunohistochemistry in section D of mouse no. 3 with an antihuman nuclear antigen (magnification, 600 ×).