Baboon SRCs are capable of engraftment into secondary recipients. Bone marrow from NOD/SCID mice transplanted with baboon CD34-enriched cells transduced with Phoenix-GALV/MNDEYFPSN (top row) or untransduced (bottom row) was harvested and injected into secondary recipients. All 4 secondary recipients engrafted at levels between 0.13% and 2%. Marking levels in the secondary recipient were similar to those in the primary recipient.