Southern-blot analysis of bcCML. Bone marrow DNA from 5 primary recipient mice (left panel) was digested with EcoRI and hybridized with a GFP probe, which detects bands of unique size for each independent viral integrant. For primary animals nos. 2, 3, and 4, 3 secondary recipients (a, b, and c) were established. The right panel shows EcoRI digestion and GFP probe analysis of the secondary recipients in comparison to each primary donor.