Representative Southern blot analysis of individual NOD/SCID mice transplanted with expanded cells from replicate flasks at week 10 of expansion. Quadruplicate cultures were initiated with 2 × 10⁴ CD34⁺ CB cells. After 10 weeks of expansion, 2 mice were injected with the corresponding progeny of initial CD34⁺ cells (1 mouse per expansion) lanes 8 to 9; 2 mice with 1/12 of the expanded cells (corresponding to initial 1,560 CD34⁺ cells) lanes 6 to 7; 2 mice with 1/32 (=625 initial cells) lanes 4 to 5; and 2 mice with 1/64 (=312 initial cells) lanes 2 to 3. Lane 1: A nonengrafted mouse (inoculated with 2 × 10⁴ CD34⁺ cells at start of cultures, plus 2 × 10⁵ CD34⁻ irradiated CB cells).