Polyclonal repopulation with hematopoietic cells containing only 1 or 2 vector integrations. (A) LAM-PCR was performed on cell lysate from CFCs plucked 1 year after transplantation of dog G115. Lane 1, 25 base pair (bp) DNA ladder; lanes 2 to 6, individual colonies; lane 7, positive control (+); lane 8, negative control (–). Of a total of 16 evaluable colonies, 14 contained 1 integration site, and only 2 contained 2 integration sites. (B) Peripheral blood samples from dog G115 at different time points after transplantation were analyzed by LAM-PCR, revealing that multiple different clones persist in the long term. Lane 1, 25 bp DNA ladder; lane 2, day 83; lane 3, day 110; lane 4, day 418; lane 5, day 453.